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Sample records for alanine aminotransferase lactate

  1. Alanine aminotransferase controls seed dormancy in barley.

    PubMed

    Sato, Kazuhiro; Yamane, Miki; Yamaji, Nami; Kanamori, Hiroyuki; Tagiri, Akemi; Schwerdt, Julian G; Fincher, Geoffrey B; Matsumoto, Takashi; Takeda, Kazuyoshi; Komatsuda, Takao

    2016-01-01

    Dormancy allows wild barley grains to survive dry summers in the Near East. After domestication, barley was selected for shorter dormancy periods. Here we isolate the major seed dormancy gene qsd1 from wild barley, which encodes an alanine aminotransferase (AlaAT). The seed dormancy gene is expressed specifically in the embryo. The AlaAT isoenzymes encoded by the long and short dormancy alleles differ in a single amino acid residue. The reduced dormancy allele Qsd1 evolved from barleys that were first domesticated in the southern Levant and had the long dormancy qsd1 allele that can be traced back to wild barleys. The reduced dormancy mutation likely contributed to the enhanced performance of barley in industrial applications such as beer and whisky production, which involve controlled germination. In contrast, the long dormancy allele might be used to control pre-harvest sprouting in higher rainfall areas to enhance global adaptation of barley. PMID:27188711

  2. Alanine aminotransferase controls seed dormancy in barley

    PubMed Central

    Sato, Kazuhiro; Yamane, Miki; Yamaji, Nami; Kanamori, Hiroyuki; Tagiri, Akemi; Schwerdt, Julian G.; Fincher, Geoffrey B.; Matsumoto, Takashi; Takeda, Kazuyoshi; Komatsuda, Takao

    2016-01-01

    Dormancy allows wild barley grains to survive dry summers in the Near East. After domestication, barley was selected for shorter dormancy periods. Here we isolate the major seed dormancy gene qsd1 from wild barley, which encodes an alanine aminotransferase (AlaAT). The seed dormancy gene is expressed specifically in the embryo. The AlaAT isoenzymes encoded by the long and short dormancy alleles differ in a single amino acid residue. The reduced dormancy allele Qsd1 evolved from barleys that were first domesticated in the southern Levant and had the long dormancy qsd1 allele that can be traced back to wild barleys. The reduced dormancy mutation likely contributed to the enhanced performance of barley in industrial applications such as beer and whisky production, which involve controlled germination. In contrast, the long dormancy allele might be used to control pre-harvest sprouting in higher rainfall areas to enhance global adaptation of barley. PMID:27188711

  3. Aspartate Aminotransferase (AST/GOT) and Alanine Aminotransferase (ALT/GPT) Detection Techniques

    PubMed Central

    Huang, Xing-Jiu; Choi, Yang-Kyu; Im, Hyung-Soon; Yarimaga, Oktay; Yoon, Euisik; Kim, Hak-Sung

    2006-01-01

    The levels of aspartate aminotransferase (AST/GOT) and alanine aminotransferase (ALT/GPT) in serum can help people diagnose body tissues especially the heart and the liver are injured or not. This article provides a comprehensive review of research activities that concentrate on AST/GOT and ALT/GPT detection techniques due to their clinical importance. The detection techniques include colorimetric, spectrophotometric, chemiluminescence, chromatography, fluorescence and UV absorbance, radiochemical, and electrochemical techniques. We devote the most attention on experimental principle. In some methods a few representative devices and important conclusions are presented.

  4. Crystal Structures of Aedes Aegypt Alanine Glyoxylate Aminotransferase

    SciTech Connect

    Han,Q.; Robinson, H.; Gao, Y.; Vogelaar, N.; Wilson, S.; Rizzi, M.; Li, J.

    2006-01-01

    Mosquitoes are unique in having evolved two alanine glyoxylate aminotransferases (AGTs). One is 3-hydroxykynurenine transaminase (HKT), which is primarily responsible for catalyzing the transamination of 3-hydroxykynurenine (3-HK) to xanthurenic acid (XA). Interestingly, XA is used by malaria parasites as a chemical trigger for their development within the mosquito. This 3-HK to XA conversion is considered the major mechanism mosquitoes use to detoxify the chemically reactive and potentially toxic 3-HK. The other AGT is a typical dipteran insect AGT and is specific for converting glyoxylic acid to glycine. Here we report the 1.75{angstrom} high-resolution three-dimensional crystal structure of AGT from the mosquito Aedes aegypti (AeAGT) and structures of its complexes with reactants glyoxylic acid and alanine at 1.75 and 2.1{angstrom} resolution, respectively. This is the first time that the three-dimensional crystal structures of an AGT with its amino acceptor, glyoxylic acid, and amino donor, alanine, have been determined. The protein is dimeric and adopts the type I-fold of pyridoxal 5-phosphate (PLP)-dependent aminotransferases. The PLP co-factor is covalently bound to the active site in the crystal structure, and its binding site is similar to those of other AGTs. The comparison of the AeAGT-glyoxylic acid structure with other AGT structures revealed that these glyoxylic acid binding residues are conserved in most AGTs. Comparison of the AeAGT-alanine structure with that of the Anopheles HKT-inhibitor complex suggests that a Ser-Asn-Phe motif in the latter may be responsible for the substrate specificity of HKT enzymes for 3-HK.

  5. Decreased alanine aminotransferase activity in serum of man during gamma-acetylenic-GABA treatment.

    PubMed

    Olsen, R; Hørder, M

    1980-06-01

    Decreasing concentrations of alanine aminotransferase were observed in nine patients receiving gamma-acetylenic-GABA, an inhibitor of GABA aminotransferase. In vitro studies showed that preincubation at 37 degrees C of serum with gamma-acetylenic-GABA and with urine from a patient receiving the drug led to inhibition of alanine aminotransferase. This inhibition of alanine aminotransferase by gamma-acetylenic-GABA was neutralized by 1-analine, the natural substrate for the enzyme. The mechanism of inhibition may be a competition between the drug and 1-alanine for the substrate binding site of the enzyme. PMID:7414257

  6. IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. International Federation of Clinical Chemistry and Laboratory Medicine. Part 7. Certification of four reference materials for the determination of enzymatic activity of gamma-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase accord.

    PubMed

    Siekmann, Lothar; Bonora, Roberto; Burtis, Carl A; Ceriotti, Ferruccio; Clerc-Renaud, Pascale; Férard, Georges; Ferrero, Carlo A; Forest, Jean-Claude; Franck, Paul F H; Gella, F-Javier; Hoelzel, Wieland; Jørgensen, Poul Jørgen; Kanno, Takashi; Kessner, Art; Klauke, Rainer; Kristiansen, Nina; Lessinger, Jean-Marc; Linsinger, Thomas P J; Misaki, Hideo; Mueller, Mathias M; Panteghini, Mauro; Pauwels, Jean; Schiele, Françoise; Schimmel, Heinz G; Vialle, Arlette; Weidemann, Gerhard; Schumann, Gerhard

    2002-07-01

    This paper is the seventh in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of Gamma-Glutamyltransferase. A document describing the determination of preliminary reference values is also in preparation. The certification of the catalytic activity concentrations as determined by the recently elaborated IFCC primary reference methods at 37 degrees C of four enzyme preparations, namely IRMM/IFCC 452 (gamma-glutamyltransferase), IRMM/IFCC 453 (lactate dehydrogenase 1), IRMM/IFCC 454 (alanine aminotransferase) and IRMM/IFCC 455 (creatine kinase) is described. Homogeneity data were derived from previous results. Stability was assessed using recently obtained data as well as data from previous stability studies. The collaborative study for value assignment was performed under a strict quality control scheme to ensure traceability to the primary reference method. Uncertainty of the materials was assessed in compliance with the Guide to the Expression of Uncertainty in Measurement. The certified values obtained at 37 degrees C are 1.90 microkat/l +/- 0.04 microkat/l (114.1 U/l +/- 2.4 U/l), for gamma-glutamyltransferase, 8.37 microkat/l +/- 0.12 microkat/l (502 U/l +/- 7 U/l), for lactate dehydrogenase 1, 3.09 microkat/l +/- 0.07 microkat

  7. Association of Alanine Aminotransferase and Periodontitis: A Cross-Sectional Analysis—NHANES 2009–2012

    PubMed Central

    Wiener, R. Constance; Sambamoorthi, Usha; Jurevic, Richard J.

    2016-01-01

    Objective. Alanine Aminotransferase is an enzyme associated with not only liver diseases, liver conditions, and metabolic syndrome, but also inflammation. Periodontitis is associated with increased cytokines and other markers of inflammation. The purpose of this study is to determine if an independent association between Alanine Aminotransferase and periodontitis exists. Methods. Data from the 2009-2010 and 2011-2012 National Health and Nutrition Surveys (NHANES) were combined. Data concerning periodontitis and Alanine Aminotransferase were extracted and analyzed with Rao Scott Chi-square and logistic regressions. Serum Alanine Aminotransferase was dichotomized at 40 units/liter, and periodontitis was dichotomized to the presence or absence of periodontitis. Results. In bivariate Chi-square analyses, periodontitis and Alanine Aminotransferase were associated (p = 0.0360) and remained significant in unadjusted logistic regression (OR = 1.30 [95% CI: 1.02, 1.65]). However, when other known risk factors of periodontitis were included in the analyses, the relationship attenuated and failed to reach significance (adjusted OR = 1.17 [95% CI: 0.85, 1.60]). Conclusion. Our study adds to the literature a positive but attenuated association of serum Alanine Aminotransferase with periodontitis which failed to reach significance when other known, strong risk factors of periodontitis were included in the analysis. PMID:26981311

  8. The value of aspartate aminotransferase and alanine aminotransferase in cardiovascular disease risk assessment

    PubMed Central

    Weng, Stephen F; Kai, Joe; Guha, Indra Neil; Qureshi, Nadeem

    2015-01-01

    Objective Aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio, reflecting liver disease severity, has been associated with increased risk of cardiovascular disease (CVD). The aim of this study was to evaluate whether the AST/ALT ratio improves established risk prediction tools in a primary care population. Methods Data were analysed from a prospective cohort of 29 316 UK primary care patients, aged 25–84 years with no history of CVD at baseline. Cox proportional hazards regression was used to derive 10-year multivariate risk models for the first occurrence of CVD based on two established risk prediction tools (Framingham and QRISK2), with and without including the AST/ALT ratio. Overall, model performance was assessed by discriminatory accuracy (AUC c-statistic). Results During a total follow-up of 120 462 person-years, 782 patients (59% men) experienced their first CVD event. Multivariate models showed that elevated AST/ALT ratios were significantly associated with CVD in men (Framingham: HR 1.37, 95% CI 1.05 to 1.79; QRISK2: HR 1.40, 95% CI 1.04 to 1.89) but not in women (Framingham: HR 1.06, 95% CI 0.78 to 1.43; QRISK2: HR 0.97, 95% CI 0.70 to 1.35). Including the AST/ALT ratio with all Framingham risk factors (AUC c-statistic: 0.72, 95% CI 0.71 to 0.74) or QRISK2 risk factors (AUC c-statistic: 0.73, 95% CI 0.71 to 0.74) resulted in no change in discrimination from the established risk prediction tools. Limiting analysis to those individuals with raised ALT showed that discrimination could improve by 5% and 4% with Framingham and QRISK2 risk factors, respectively. Conclusions Elevated AST/ALT ratio is significantly associated with increased risk of developing CVD in men but not women. However, the ratio does not confer any additional benefits over established CVD risk prediction tools in the general population, but may have clinical utility in certain subgroups. PMID:26322236

  9. Beta-alanine/alpha-ketoglutarate aminotransferase for 3-hydroxypropionic acid production

    DOEpatents

    Jessen, Holly Jean; Liao, Hans H; Gort, Steven John; Selifonova, Olga V

    2014-11-18

    The present disclosure provides novel beta-alanine/alpha ketoglutarate aminotransferase nucleic acid and protein sequences having increased biological activity. Also provided are cells containing such enzymes, as well as methods of their use, for example to produce malonyl semialdehyde and downstream products thereof, such as 3-hydroxypropionic acid and derivatives thereof.

  10. Beta-alanine/alpha-ketoglutarate aminotransferase for 3-hydroxypropionic acid production

    DOEpatents

    Jessen, Holly Jean; Liao, Hans H.; Gort, Steven John; Selifonova, Olga V.

    2011-10-04

    The present disclosure provides novel beta-alanine/alpha ketoglutarate aminotransferase nucleic acid and protein sequences having increased biological activity. Also provided are cells containing such enzymes, as well as methods of their use, for example to produce malonyl semialdehyde and downstream products thereof, such as 3-hydroxypropionic acid and derivatives thereof.

  11. Protein Homeostasis Defects of Alanine-Glyoxylate Aminotransferase: New Therapeutic Strategies in Primary Hyperoxaluria Type I

    PubMed Central

    Pey, Angel L.; Albert, Armando; Salido, Eduardo

    2013-01-01

    Alanine-glyoxylate aminotransferase catalyzes the transamination between L-alanine and glyoxylate to produce pyruvate and glycine using pyridoxal 5′-phosphate (PLP) as cofactor. Human alanine-glyoxylate aminotransferase is a peroxisomal enzyme expressed in the hepatocytes, the main site of glyoxylate detoxification. Its deficit causes primary hyperoxaluria type I, a rare but severe inborn error of metabolism. Single amino acid changes are the main type of mutation causing this disease, and considerable effort has been dedicated to the understanding of the molecular consequences of such missense mutations. In this review, we summarize the role of protein homeostasis in the basic mechanisms of primary hyperoxaluria. Intrinsic physicochemical properties of polypeptide chains such as thermodynamic stability, folding, unfolding, and misfolding rates as well as the interaction of different folding states with protein homeostasis networks are essential to understand this disease. The view presented has important implications for the development of new therapeutic strategies based on targeting specific elements of alanine-glyoxylate aminotransferase homeostasis. PMID:23956997

  12. A novel low molecular weight alanine aminotransferase from fasted rat liver.

    PubMed

    Vedavathi, M; Girish, K S; Kumar, M Karuna

    2006-01-01

    Alanine is the most effective precursor for gluconeogenesis among amino acids, and the initial reaction is catalyzed by alanine aminotransferase (AlaAT). Although the enzyme activity increases during fasting, this effect has not been studied extensively. The present study describes the purification and characterization of an isoform of AlaAT from rat liver under fasting. The molecular mass of the enzyme is 17.7 kD with an isoelectric point of 4.2; glutamine is the N-terminal residue. The enzyme showed narrow substrate specificity for L-alanine with Km values for alanine of 0.51 mM and for 2-oxoglutarate of 0.12 mM. The enzyme is a glycoprotein. Spectroscopic and inhibition studies showed that pyridoxal phosphate (PLP) and free -SH groups are involved in the enzymatic catalysis. PLP activated the enzyme with a Km of 0.057 mM. PMID:16487061

  13. Isolation and characterization of cytosolic alanine aminotransferase isoforms from starved rat liver.

    PubMed

    Vedavathi, M; Girish, K S; Kumar, M Karuna

    2004-12-01

    Alanine is the most effective precursor for gluconeogenesis among amino acids and the initial reaction is catalyzed by alanine aminotransferases (AlaATs). It is a less extensively studied enzyme under starvation and known to that the enzyme activity increases in liver under starvation. The present study describes the purification and characterization of two isoforms of alanine aminotransferases from starved male rat liver under starvation. The molecular mass of isoforms was found to be 17.7 and 112.2 kDa with isoelectric points of 4.2 and 5.3 respectively for AlaAT I and AlaAT II. Both the enzymes showed narrow substrate specificity for L-alanine with different Km for alanine and 2-oxoglutarate. Both the enzymes were glycoprotein in nature. Inhibition, modification and spectroscopic studies showed that both PLP and free-SH groups are directly involved in the enzymatic catalysis. PLP activated both the enzymes with a Km 0.057 mM and 0.2 mM for AlaAT I and II respectively. PMID:15663181

  14. Serum γ-Glutamyltransferase, Alanine Aminotransferase and Aspartate Aminotransferase Activity in Healthy Blood Donor of Different Ethnic Groups in Gorgan

    PubMed Central

    Mehrpouya, Masoumeh; Pourhashem, Zeinab

    2016-01-01

    Introduction Measure of liver enzymes may help to increase safety of blood donation for both blood donor and recipient. Determination of liver enzymes may prepare valuable clinical information. Aim To assess serum γ-Glutamyltransferase (GGT), Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST) activities in healthy blood donors in different ethnic groups in Gorgan. Materials and Methods This study was performed in 450 healthy male blood donors, in three ethnic groups (Fars, Sistanee and Turkman) who attended Gorgan blood transfusion center. Liver enzymes (GGT, ALT and AST) were determined. Results Serum AST and ALT in three ethnic groups were significant except for serum GGT levels. There was significant correlation between family histories of liver disease and systolic blood pressure and AST in Fars, and GGT in Sistanee ethnic groups. Conclusion Several factors, such as age, family history of diabetes mellitus, family history of liver disease and smoking habit had no effect on some liver enzymes in different ethnic groups in this area. Variation of AST, ALT, and GGT enzyme activities in healthy subjects was associated with some subjects in our study groups. According to our study, it suggests that screening of AST and GGT enzymes in subjects with family history of liver disease is necessary in different ethnic groups.

  15. Alanine aminotransferase as a predictor of adverse perinatal outcomes in women with intrahepatic cholestasis of pregnancy

    PubMed Central

    Ekiz, Ali; Kaya, Basak; Avci, Muhittin Eftal; Polat, Ibrahim; Dikmen, Selin; Yildirim, Gokhan

    2016-01-01

    Objective: To evaluate the associations between adverse perinatal outcomes and serum transaminase levels at the time of diagnosis in patients with intrahepatic cholestasis of pregnancy. Methods: We performed a retrospective analysis of patients hospitalized for evaluation of intrahepatic cholestasis of pregnancy from January 2013 to June 2014 in a tertiary center. Seventy-one patients were divided into two groups according to the presence (Group I) or absence of adverse perinatal outcomes (Group II). Results: The mean aminotransferase levels and conjugated bilirubin levels at the time of diagnosis were significantly higher in Group I than in Group II. Receiver operating characteristic curve analysis revealed that the alanine aminotransferase level could predict adverse perinatal outcomes with 76.47% sensitivity and 78.38% specificity, and the cut-off value was 95 IU/L. Among patients with intrahepatic cholestasis of pregnancy, those with adverse perinatal outcomes were significantly older, had an earlier diagnosis, and had higher alanine aminotransferase levels. Using the 95-IU/L cut-off value, patients with intrahepatic cholestasis of pregnancy had a 3.54-fold increased risk for adverse perinatal outcomes. Conclusions: Patients with intrahepatic cholestasis of pregnancy and high alanineaminotransferase levels should be followed up for possible adverse perinatal outcomes.

  16. PPAR{alpha} regulates the hepatotoxic biomarker alanine aminotransferase (ALT1) gene expression in human hepatocytes

    SciTech Connect

    Thulin, Petra; Rafter, Ingalill; Stockling, Kenneth; Tomkiewicz, Celine; Norjavaara, Ensio; Aggerbeck, Martine; Hellmold, Heike; Ehrenborg, Ewa; Andersson, Ulf; Cotgreave, Ian; Glinghammar, Bjoern

    2008-08-15

    In this work, we investigated a potential mechanism behind the observation of increased aminotransferase levels in a phase I clinical trial using a lipid-lowering drug, the peroxisome proliferator-activated receptor (PPAR) {alpha} agonist, AZD4619. In healthy volunteers treated with AZD4619, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were elevated without an increase in other markers for liver injury. These increases in serum aminotransferases have previously been reported in some patients receiving another PPAR{alpha} agonist, fenofibrate. In subsequent in vitro studies, we observed increased expression of ALT1 protein and mRNA in human hepatocytes after treatment with fenofibric acid. The PPAR effect on ALT1 expression was shown to act through a direct transcriptional mechanism involving at least one PPAR response element (PPRE) in the proximal ALT1 promoter, while no effect of fenofibrate and AZD4619 was observed on the ALT2 promoter. Binding of PPARs to the PPRE located at - 574 bp from the transcriptional start site was confirmed on both synthetic oligonucleotides and DNA in hepatocytes. These data show that intracellular ALT expression is regulated by PPAR agonists and that this mechanism might contribute to increased ALT activity in serum.

  17. Evaluation of drug-induced tissue injury by measuring alanine aminotransferase (ALT) activity in silkworm hemolymph

    PubMed Central

    2012-01-01

    Background Our previous studies suggest silkworms can be used as model animals instead of mammals in pharmacologic studies to develop novel therapeutic medicines. We examined the usefulness of the silkworm larvae Bombyx mori as an animal model for evaluating tissue injury induced by various cytotoxic drugs. Drugs that induce hepatotoxic effects in mammals were injected into the silkworm hemocoel, and alanine aminotransferase (ALT) activity was measured in the hemolymph 1 day later. Results Injection of CCl4 into the hemocoel led to an increase in ALT activity. The increase in ALT activity was attenuated by pretreatment with N-acetyl-L-cysteine. Injection of benzoic acid derivatives, ferric sulfate, sodium valproate, tetracycline, amiodarone hydrochloride, methyldopa, ketoconazole, pemoline (Betanamin), N-nitroso-fenfluramine, and D-galactosamine also increased ALT activity. Conclusions These findings indicate that silkworms are useful for evaluating the effects of chemicals that induce tissue injury in mammals. PMID:23137391

  18. Multiple adaptive losses of alanine-glyoxylate aminotransferase mitochondrial targeting in fruit-eating bats.

    PubMed

    Liu, Yang; Xu, Huihui; Yuan, Xinpu; Rossiter, Stephen J; Zhang, Shuyi

    2012-06-01

    The enzyme alanine-glyoxylate aminotransferase 1 (AGT) functions to detoxify glyoxylate before it is converted into harmful oxalate. In mammals, mitochondrial targeting of AGT in carnivorous species versus peroxisomal targeting in herbivores is controlled by two signal peptides that correspond to these respective organelles. Differential expression of the mitochondrial targeting sequence (MTS) is considered an adaptation to diet-specific subcellular localization of glyoxylate precursors. Bats are an excellent group in which to study adaptive changes in dietary enzymes; they show unparalleled mammalian dietary diversification as well as independent origins of carnivory, frugivory, and nectarivory. We studied the AGT gene in bats and other mammals with diverse diets and found that the MTS has been lost in unrelated lineages of frugivorous bats. Conversely, species exhibiting piscivory, carnivory, insectivory, and sanguinivory possessed intact MTSs. Detected positive selection in the AGT of ancestral fruit bats further supports adaptations related to evolutionary changes in diet. PMID:22319153

  19. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.

    PubMed

    Mazzalupo, Stacy; Isoe, Jun; Belloni, Virginia; Scaraffia, Patricia Y

    2016-01-01

    To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.-Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase. PMID:26310269

  20. Screening for genetic haemochromatosis in blood samples with raised alanine aminotransferase

    PubMed Central

    Bhavnani, M; Lloyd, D; Bhattacharyya, A; Marples, J; Elton, P; Worwood, M

    2000-01-01

    BACKGROUND—In the UK approximately 1 in 140 people are homozygous for the C282Y mutation of the HFE gene and are at risk from iron overload caused by genetic haemochromatosis (GH). Early detection can prevent organ damage secondary to iron deposition and increase life expectancy.
AIM—To screen for GH in all blood samples sent to the laboratory for routine liver function tests in which raised serum alanine aminotransferase (ALT) activity was detected.
METHODS—ALT was measured in sera sent to the laboratory for routine liver function tests. In those samples found to have raised activity, transferrin saturation and ferritin were measured followed by genetic testing when transferrin saturation was increased.
RESULTS—Of the 35 069 serum samples assayed for routine liver function tests, 1490 (4.2%) had raised ALT levels (>50 u/l). Transferrin saturation and serum ferritin concentrations were measured in these patient samples, and in 56 transferrin saturation was >60%. Further blood samples were requested from these patients for genetic testing: 33 samples were obtained. There were nine patients homozygous for the C282Y mutation of the HFE gene and three compound heterozygotes (heterozygous for both C282Y and H63D mutations).
CONCLUSIONS—The association of raised ALT activity and transferrin saturation of >60% could provide a simple, cost effective method for detecting individuals with clinical haemochromatosis. Although many patients with GH may have been missed, this study suggests that the clinical penetrance of the disorder may be much lower than is generally supposed and that genetic screening will identify many people who may never develop clinical haemochromatosis.


Keywords: haemochromatosis; alanine aminotransferase PMID:10764716

  1. Relationship between lactate and glutamine metabolism in vitro by the kidney: differences between dog and rat and importance of alanine synthesis in the dog.

    PubMed

    Lemieux, G; Vinay, P; Baverel, G; Brière, R; Gougoux, A

    1979-10-01

    Interaction between lactate (1 or 5 mM) and glutamine (1 or 5 mM) metabolism was studied with renal cortical slices incubated at a pH of 7.0 and obtained from acidotic (ammonium chloride) dogs and rats. The effect of aminooxyacetate (0.2 mM), dichloroacetate (3 mM), and fluoroacetate (0.05 mM) was also studied. Significant differences were observed between dog and rat. In the dog, lactate had no effect on glutamine uptake and vice versa, but gluconeogenesis increased. Ammonia production, however, decreased by 13 to 21%, whereas a significant increase in alanine production was noted. In the rat, glutamine extraction and ammonia production dropped by 33% with 5 mM lactate. In contrast to the observation in the dog, no production of alanine was noted, but significant accumulation of glutamate took place. Amino-oxyacetate inhibited alanine production in the dog and reestablished ammoniagenesis, and it led to a marked decrement in the uptake of lactate and glucose production in both species. Dichloroacetate in the dog resulted in a reduction in pyruvate, alanine, glucose, and ammonia production while glutamate accumulation was observed. In both species, fluoroacetate stimulated glutamine uptake and ammonia production. With lactate alone, fluoroacetate decreased lactate uptake and glucose production. With both lactate and glutamine in the medium, fluoroacetate prevented any effect of lactate on ammoniagenesis. The present study demonstrates that lactate has a modest depressing effect on renal ammonia production by dog slices through increased synthesis of alanine and redistribution of nitrogen from glutamine. In the rat, the depressing effect of lactate on ammonia production in the alanine amino-transferase deficient kidney occurs through accumulation of glutamate. The data also reveal that oxidation of lactate to carbon dioxide is greater in the dog than it is in the rat, but that gluconeogenesis from lactate is more important in the rat. PMID:548591

  2. Cytokeratin 18, Alanine Aminotransferase, Platelets and Triglycerides Predict the Presence of Nonalcoholic Steatohepatitis

    PubMed Central

    Cao, Wei; Zhao, Caiyan; Shen, Chuan; Wang, Yadong

    2013-01-01

    Background Nonalcoholic fatty liver disease (NAFLD) is one of the critical public health problems in China. The full spectrum of the disease ranges from simple steatosis and nonalcoholic steatohepatitis (NASH) to cirrhosis and hepatocellular carcinoma(HCC). The infiltration of inflammatory cells characterizes NASH. This characteristic contributes to the progression of hepatitis, fibrosis, cirrhosis, and HCC. Therefore, distinguishing NASH from NAFLD is crucial. Objective and Methods Ninety-five patients with NAFLD, 44 with NASH, and 51 with non-NASH were included in the study to develop a new scoring system for differentiating NASH from NAFLD. Data on clinical and biological characteristics, as well as blood information, were obtained. Cytokeratin-18 (CK-18) fragments levels were measured using an enzyme-linked immunosorbant assay. Results Several indexes show significant differences between the two groups, which include body mass index (BMI), waist-on-hip ratio (WHR), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), γ-glutamyl transpeptidase (γ-GT), platelets, uric acid (UA), hs-C-reactive protein (hs-CRP), triglycerides (TG), albumin (ALB), and CK-18 fragments (all P < 0.05). The CK-18 fragment levels showed a significant positive correlation with steatosis severity, ballooning, lobular inflammation, and fibrosis stage (all P < 0.05). Therefore, a new model that combines ALT, platelets, CK-18 fragments, and TG was established by logistic regression among NAFLD patients. The AUROC curve in predicting NASH was 0.920 (95% CI: 0.866 - 0.974, cutoff value = 0.361, sensitivity = 89%, specificity = 86%, positive predictive value = 89%, negative predictive value = 89%). Conclusion The novel scoring system may be considered as a useful model in predicting the presence of NASH in NAFLD patients. PMID:24324749

  3. Irritable Bowel Syndrome May Be Associated with Elevated Alanine Aminotransferase and Metabolic Syndrome

    PubMed Central

    Lee, Seung-Hwa; Kim, Kwang-Min; Joo, Nam-Seok

    2016-01-01

    Purpose Recent studies have revealed close relationships between hepatic injury, metabolic pathways, and gut microbiota. The microorganisms in the intestine also cause irritable bowel syndrome (IBS). The aim of this study was to examine whether IBS was associated with elevated hepatic enzyme [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)], gamma-glutamyl transferase (γ-GT) levels, and metabolic syndrome (MS). Materials and Methods This was a retrospective, cross-sectional, case-control study. The case and control groups comprised subjects who visited our health promotion center for general check-ups from June 2010 to December 2010. Of the 1127 initially screened subjects, 83 had IBS according to the Rome III criteria. The control group consisted of 260 age- and sex-matched subjects without IBS who visited our health promotion center during the same period. Results Compared to control subjects, patients with IBS showed significantly higher values of anthropometric parameters (body mass index, waist circumference), liver enzymes, γ-GT, and lipid levels. The prevalences of elevated ALT (16.9% vs. 7.7%; p=0.015) and γ-GT (24.1% vs. 11.5%; p=0.037) levels were significantly higher in patients with IBS than in control subjects. A statistically significant difference was observed in the prevalence of MS between controls and IBS patients (12.7% vs. 32.5%; p<0.001). The relationships between elevated ALT levels, MS, and IBS remained statistically significant after controlling for potential confounding factors. Conclusion On the basis of our study results, IBS may be an important condition in certain patients with elevated ALT levels and MS. PMID:26632395

  4. A Micro-Platinum Wire Biosensor for Fast and Selective Detection of Alanine Aminotransferase

    PubMed Central

    Thuy, Tran Nguyen Thanh; Tseng, Tina T.-C.

    2016-01-01

    In this study, a miniaturized biosensor based on permselective polymer layers (overoxidized polypyrrole (Ppy) and Nafion®) modified and enzyme (glutamate oxidase (GlutOx)) immobilized micro-platinum wire electrode for the detection of alanine aminotransferase (ALT) was fabricated. The proposed ALT biosensor was measured electrochemically by constant potential amperometry at +0.7 V vs. Ag/AgCl. The ALT biosensor provides fast response time (~5 s) and superior selectivity towards ALT against both negatively and positively charged species (e.g., ascorbic acid (AA) and dopamine (DA), respectively). The detection range of the ALT biosensor is found to be 10–900 U/L which covers the range of normal ALT levels presented in the serum and the detection limit and sensitivity are found to be 8.48 U/L and 0.059 nA/(U/L·mm2) (N = 10), respectively. We also found that one-day storage of the ALT biosensor at −20 °C right after the sensor being fabricated can enhance the sensor sensitivity (1.74 times higher than that of the sensor stored at 4 °C). The ALT biosensor is stable after eight weeks of storage at −20 °C. The sensor was tested in spiked ALT samples (ALT activities: 20, 200, 400, and 900 U/L) and reasonable recoveries (70%~107%) were obtained. PMID:27240366

  5. A Micro-Platinum Wire Biosensor for Fast and Selective Detection of Alanine Aminotransferase.

    PubMed

    Thuy, Tran Nguyen Thanh; Tseng, Tina T-C

    2016-01-01

    In this study, a miniaturized biosensor based on permselective polymer layers (overoxidized polypyrrole (Ppy) and Nafion(®)) modified and enzyme (glutamate oxidase (GlutOx)) immobilized micro-platinum wire electrode for the detection of alanine aminotransferase (ALT) was fabricated. The proposed ALT biosensor was measured electrochemically by constant potential amperometry at +0.7 V vs. Ag/AgCl. The ALT biosensor provides fast response time (~5 s) and superior selectivity towards ALT against both negatively and positively charged species (e.g., ascorbic acid (AA) and dopamine (DA), respectively). The detection range of the ALT biosensor is found to be 10-900 U/L which covers the range of normal ALT levels presented in the serum and the detection limit and sensitivity are found to be 8.48 U/L and 0.059 nA/(U/L·mm²) (N = 10), respectively. We also found that one-day storage of the ALT biosensor at -20 °C right after the sensor being fabricated can enhance the sensor sensitivity (1.74 times higher than that of the sensor stored at 4 °C). The ALT biosensor is stable after eight weeks of storage at -20 °C. The sensor was tested in spiked ALT samples (ALT activities: 20, 200, 400, and 900 U/L) and reasonable recoveries (70%~107%) were obtained. PMID:27240366

  6. Associations of functional alanine-glyoxylate aminotransferase 2 gene variants with atrial fibrillation and ischemic stroke.

    PubMed

    Seppälä, Ilkka; Kleber, Marcus E; Bevan, Steve; Lyytikäinen, Leo-Pekka; Oksala, Niku; Hernesniemi, Jussi A; Mäkelä, Kari-Matti; Rothwell, Peter M; Sudlow, Cathie; Dichgans, Martin; Mononen, Nina; Vlachopoulou, Efthymia; Sinisalo, Juha; Delgado, Graciela E; Laaksonen, Reijo; Koskinen, Tuomas; Scharnagl, Hubert; Kähönen, Mika; Markus, Hugh S; März, Winfried; Lehtimäki, Terho

    2016-01-01

    Asymmetric and symmetric dimethylarginines (ADMA and SDMA) impair nitric oxide bioavailability and have been implicated in the pathogenesis of atrial fibrillation (AF). Alanine-glyoxylate aminotransferase 2 (AGXT2) is the only enzyme capable of metabolizing both of the dimethylarginines. We hypothesized that two functional AGXT2 missense variants (rs37369, V140I; rs16899974, V498L) are associated with AF and its cardioembolic complications. Association analyses were conducted using 1,834 individulas with AF and 7,159 unaffected individuals from two coronary angiography cohorts and a cohort comprising patients undergoing clinical exercise testing. In coronary angiography patients without structural heart disease, the minor A allele of rs16899974 was associated with any AF (OR = 2.07, 95% CI 1.59-2.68), and with paroxysmal AF (OR = 1.98, 95% CI 1.44-2.74) and chronic AF (OR = 2.03, 95% CI 1.35-3.06) separately. We could not replicate the association with AF in the other two cohorts. However, the A allele of rs16899974 was nominally associated with ischemic stroke risk in the meta-analysis of WTCCC2 ischemic stroke cohorts (3,548 cases, 5,972 controls) and with earlier onset of first-ever ischemic stroke (360 cases) in the cohort of clinical exercise test patients. In conclusion, AGXT2 variations may be involved in the pathogenesis of AF and its age-related thromboembolic complications. PMID:26984639

  7. Subcellular localization of branched-chain amino acid aminotransferase and lactate dehydrogenase C4 in rat and mouse spermatozoa.

    PubMed Central

    Montamat, E E; Vermouth, N T; Blanco, A

    1988-01-01

    Spermatozoa isolated from rat and mouse epididymes show a relatively high branched-chain amino acid aminotransferase (leucine aminotransferase, EC 2.6.1.6) activity. There is a significant reduction of leucine aminotransferase and of the isoenzyme C4 of lactate dehydrogenase (EC 1.1.1.27) in the gametes during their epididymal transit. Studies of patterns of liberation of the leucine aminotransferase and of the lactate dehydrogenase C4 from intact spermatozoa, treated with increasing concentrations of digitonin, indicate that both enzymes have the same dual subcellular location, i.e. in the cytosol and in the mitochondria. PMID:3214422

  8. Subcellular localization of branched-chain amino acid aminotransferase and lactate dehydrogenase C4 in rat and mouse spermatozoa.

    PubMed

    Montamat, E E; Vermouth, N T; Blanco, A

    1988-11-01

    Spermatozoa isolated from rat and mouse epididymes show a relatively high branched-chain amino acid aminotransferase (leucine aminotransferase, EC 2.6.1.6) activity. There is a significant reduction of leucine aminotransferase and of the isoenzyme C4 of lactate dehydrogenase (EC 1.1.1.27) in the gametes during their epididymal transit. Studies of patterns of liberation of the leucine aminotransferase and of the lactate dehydrogenase C4 from intact spermatozoa, treated with increasing concentrations of digitonin, indicate that both enzymes have the same dual subcellular location, i.e. in the cytosol and in the mitochondria. PMID:3214422

  9. Reconfiguration of N Metabolism upon Hypoxia Stress and Recovery: Roles of Alanine Aminotransferase (AlaAT) and Glutamate Dehydrogenase (GDH)

    PubMed Central

    Diab, Houssein; Limami, Anis M.

    2016-01-01

    In the context of climatic change, more heavy precipitation and more frequent flooding and waterlogging events threaten the productivity of arable farmland. Furthermore, crops were not selected to cope with flooding- and waterlogging-induced oxygen limitation. In general, low oxygen stress, unlike other abiotic stresses (e.g., cold, high temperature, drought and saline stress), received little interest from the scientific community and less financial support from stakeholders. Accordingly, breeding programs should be developed and agronomical practices should be adapted in order to save plants’ growth and yield—even under conditions of low oxygen availability (e.g., submergence and waterlogging). The prerequisite to the success of such breeding programs and changes in agronomical practices is a good knowledge of how plants adapt to low oxygen stress at the cellular and the whole plant level. In the present paper, we summarized the recent knowledge on metabolic adjustment in general under low oxygen stress and highlighted thereafter the major changes pertaining to the reconfiguration of amino acids syntheses. We propose a model showing (i) how pyruvate derived from active glycolysis upon hypoxia is competitively used by the alanine aminotransferase/glutamate synthase cycle, leading to alanine accumulation and NAD+ regeneration. Carbon is then saved in a nitrogen store instead of being lost through ethanol fermentative pathway. (ii) During the post-hypoxia recovery period, the alanine aminotransferase/glutamate dehydrogenase cycle mobilizes this carbon from alanine store. Pyruvate produced by the reverse reaction of alanine aminotransferase is funneled to the TCA cycle, while deaminating glutamate dehydrogenase regenerates, reducing equivalent (NADH) and 2-oxoglutarate to maintain the cycle function. PMID:27258319

  10. Reconfiguration of N Metabolism upon Hypoxia Stress and Recovery: Roles of Alanine Aminotransferase (AlaAT) and Glutamate Dehydrogenase (GDH).

    PubMed

    Diab, Houssein; Limami, Anis M

    2016-01-01

    In the context of climatic change, more heavy precipitation and more frequent flooding and waterlogging events threaten the productivity of arable farmland. Furthermore, crops were not selected to cope with flooding- and waterlogging-induced oxygen limitation. In general, low oxygen stress, unlike other abiotic stresses (e.g., cold, high temperature, drought and saline stress), received little interest from the scientific community and less financial support from stakeholders. Accordingly, breeding programs should be developed and agronomical practices should be adapted in order to save plants' growth and yield-even under conditions of low oxygen availability (e.g., submergence and waterlogging). The prerequisite to the success of such breeding programs and changes in agronomical practices is a good knowledge of how plants adapt to low oxygen stress at the cellular and the whole plant level. In the present paper, we summarized the recent knowledge on metabolic adjustment in general under low oxygen stress and highlighted thereafter the major changes pertaining to the reconfiguration of amino acids syntheses. We propose a model showing (i) how pyruvate derived from active glycolysis upon hypoxia is competitively used by the alanine aminotransferase/glutamate synthase cycle, leading to alanine accumulation and NAD⁺ regeneration. Carbon is then saved in a nitrogen store instead of being lost through ethanol fermentative pathway. (ii) During the post-hypoxia recovery period, the alanine aminotransferase/glutamate dehydrogenase cycle mobilizes this carbon from alanine store. Pyruvate produced by the reverse reaction of alanine aminotransferase is funneled to the TCA cycle, while deaminating glutamate dehydrogenase regenerates, reducing equivalent (NADH) and 2-oxoglutarate to maintain the cycle function. PMID:27258319

  11. Anthropometric Indices in Adults: Which Is the Best Indicator to Identify Alanine Aminotransferase Levels?

    PubMed Central

    Chen, Shuang; Guo, Xiaofan; Yu, Shasha; Zhou, Ying; Li, Zhao; Sun, Yingxian

    2016-01-01

    Background: To evaluate the correlations between serum alanine aminotransferase (ALT) levels and anthropometric indices including body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR), and a new body index, the A Body Shape Index (ABSI) in Chinese adults. Methods: A multicenter, cross-sectional study was conducted in rural areas of China in 2012–2013, and 11,331 adults were included in our final analysis. Results: BMI, WC, HC, WHtR, WHR and ABSI were significantly positively correlated with ALT levels. Spearman rank test showed that WHtR (r = 0.346 for men, r = 0.282 for women, both p < 0.001) had the highest correlation coefficient for ALT level, whereas ABSI showed the lowest, and the correlation coefficient of each measure was higher in men than that in women. Comparing the lowest with the highest quintile of each anthropometric measure, the multivariate logistic model presented that WHtR had the superiority of identifying the presence of elevated ALT (OR 4.38; 95% CI 3.15–6.08 for men, OR 4.29; 95% CI 2.91–6.33 for women, both p < 0.001), and the ABSI was the poorest predictor in men (OR 2.51; 95% CI 1.93–3.27, p < 0.001). No association was observed for ABSI in women. Conclusions: Our results indicated that BMI, WC, HC, WHtR and WHR were able to determine elevated ALT presence, while ABSI was not capable. WHtR and to some extent BMI were the best body indices, for predicting the ALT levels in this population. Nevertheless, the predictive ability of ABSI as a novel body index was not superior compared to established anthropometric indices. PMID:26901214

  12. The associations of physical activity and adiposity with alanine aminotransferase and gamma-glutamyltransferase.

    PubMed

    Lawlor, Debbie A; Sattar, Naveed; Smith, George Davey; Ebrahim, Shah

    2005-06-01

    The mechanisms linking obesity and inactivity to diabetes mellitus are unclear. Recent studies have shown associations of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) with diabetes. In a random sample of 3,789 British women aged 60-79 years, the authors examined the associations of obesity and physical activity with ALT and GGT (1999-2001). Both body mass index and waist:hip ratio were independently (of each other, physical activity, alcohol consumption, smoking, and childhood and adulthood social class) positively and linearly associated with ALT and GGT. In adjusted models, a one-standard-deviation increase in body mass index was associated with a 0.46-units/liter (95% confidence interval (CI): 0.16, 0.75) increase in ALT and a 2.14-units/liter (95% CI: 0.99, 3.30) increase in GGT. Similar results for a one-standard-deviation increase in waist:hip ratio were 13.96 (95% CI: 10.44, 17.48) for ALT and 39.44 (95% CI: 25.89, 52.98) for GGT. Frequency of physical activity was inversely and linearly associated with GGT in fully adjusted models, but the inverse association with ALT was attenuated towards the null after adjustment for body mass index and waist:hip ratio. Adjustment for ALT and GGT resulted in some attenuation of the strong linear associations of body mass index and waist:hip ratio with diabetes. These findings provide some support for the suggestion that the relation between obesity and diabetes is, at least in part, mediated by liver pathology. PMID:15901629

  13. Association between Elevated Alanine Aminotransferase and Urosepsis in Children with Acute Pyelonephritis

    PubMed Central

    Kim, Dongwan; Lee, Sung Hyun; Ryoo, Eell; Cho, Hye Kyung; Kim, Yun Mi

    2016-01-01

    Purpose The aim of this study is to investigate the association between elevated alanine aminotransferase (ALT) and urosepsis in children with acute pyelonephritis (APN). Methods We retrospectively identified all children who were managed in our hospital with APN during a decade period. In our study a diagnosis of APN was defined as having a positive urine culture and a positive (99m)Tc-dimercaptosuccinic acid scintigraphy. We compared those with elevated ALT and those with normal ALT according to the following variables: age, gender, duration of fever prior to admission, presence of hypotension, C-reactive protein (CRP), creatinine, presence of anemia, white blood cells count, platelet count, blood culture result, and grades of vesicoureteral reflux. In addition, the correlation between elevated ALT and positive blood culture was analyzed in detail. Results A total of 996 children were diagnosed with APN, of which 883 were included in the study. ALT was elevated in 81 children (9.2%). In the analysis of demographic characteristics, the number of children with elevated ALT was higher in children between 0 to 3 months, boys, and in those with positive blood culture (p=0.002, 0.036, and 0.010, respectively). In multivariate analysis of variables associated with positive blood culture, age younger than 3 months, elevated ALT, elevated CRP, and elevated creatinine showed statistical significance (p=0.004, 0.030, 0.043, and 0.044, respectively). Conclusion Our study demonstrates the association between elevated ALT and increased prevalence of urosepsis in addition to elevated CRP, elevated creatinine, and age younger than 3 months in children with APN. PMID:27066449

  14. Upper Limits of Normal for Serum Alanine Aminotransferase Levels in Chinese Han Population

    PubMed Central

    Zheng, Ming-Hua; Shi, Ke-Qing; Fan, Yu-Chen; Liu, Wen-Yue; Lin, Xian-Feng; Li, Ling-Fei; Chen, Yong-Ping

    2012-01-01

    Background and Objectives Serum alanine aminotransferase (ALT) activity is the most common tool for the assessment of liver diseases. However, it is not clear whether the current normal ALT range really discriminate patients with or without liver diseases. The present study was to establish a new normal range of ALT and examine its ability to identify patients with hepatitis B or nonalcoholic fatty liver disease (NAFLD) in Chinese Han population. Methods 53037 adults were included in this study from January 1st 2008 to August 31st 2010. The 95th percentile of ALT in population with relative low risk factors for liver diseases was set as the new upper limits of normal ALT in gender-specific manner. Results The 95th percentile levels at low risk factors for liver diseases were achieved at 35 U/L for men and 23 U/L for women. The concordance statistics for detection were 0.873 (95%CI: 0.865–0.881) for HBV and 0.932 (95%CI: 0.927–0.937) for NAFLD in men while 0.857 (95%CI: 0.850–0.864) for HBV and 0.909 (95%CI: 0.903–0.915) for NAFLD in women. The median sensitivity of the current used ALT upper limit (40 U/L) was 6.6% for HBV and 29.7% for NAFLD and median specificity was 98.7% for men and 99.4% for women. Using our new-derived thresholds, the sensitivities ranged from 35.3% to 61.1% and the specificities were 94.8% for men and 94.6% for women. Conclusions Our results suggest that upper limits of ALT 35 U/L for men and 23 U/L for women in Chinese Han population. Re-consideration of normal limits of ALT should be recommended. Trial Registration ChiCTR.org ChiCTR-OCS-11001173 PMID:22962588

  15. Correlation between liver cell necrosis and circulating alanine aminotransferase after ischaemia/reperfusion injuries in the rat liver.

    PubMed

    Knudsen, Anders R; Andersen, Kasper J; Hamilton-Dutoit, Stephen; Nyengaard, Jens R; Mortensen, Frank V

    2016-04-01

    Circulating liver enzymes such as alanine transaminase are often used as markers of hepatocellular damage. Ischaemia/reperfusion (I/R) injury is an inevitable consequence of prolonged liver ischaemia. The aim of this study was to examine the correlation between liver enzymes and volume of liver cell necrosis after ischaemia/reperfusion injuries, using design-unbiased stereological methods. Forty-seven male Wistar rats were subjected to 1 h of partial liver ischaemia, followed by either 4 or 24 h of reperfusion. Within each group, one-third of animals were subjected to ischaemic preconditioning and one-third to ischaemic postconditioning. At the end of reperfusion, blood and liver samples were collected for analysis. The volume of necrotic liver tissue was subsequently correlated to circulating markers of I/R injury. Correlation between histological findings and circulating markers was performed using Pearson's correlation coefficient. Alanine transferase peaked after 4 h of reperfusion; however, at this time-point, only mild necrosis was observed, with a Pearson's correlation coefficient of 0.663 (P = 0.001). After 24 h of reperfusion, alanine aminotransferase was found to be highly correlated to the degree of hepatocellular necrosis R = 0.836 (P = 0.000). Furthermore, alkaline phosphatase (R = 0.806) and α-2-macroglobulin (R = 0.655) levels were also correlated with the degree of necrosis. We show for the first time that there is a close correlation between the volume of hepatocellular necrosis and alanine aminotransferase levels in a model of I/R injury. This is especially apparent after 24 h of reperfusion. Similarly, increased levels of alkaline phosphatase and α-2-macroglobulin are correlated to the volume of liver necrosis. PMID:27292534

  16. Alanine Aminotransferase Is Associated with an Adverse Nocturnal Blood Glucose Profile in Individuals with Normal Glucose Regulation

    PubMed Central

    Li, Hong; Ran, Xingwu; Yang, Wenying; Li, Qiang; Peng, Yongde; Li, Yanbing; Gao, Xin; Luan, Xiaojun; Wang, Weiqing; Jia, Weiping

    2013-01-01

    Objective Although the association between alanine aminotransferase (ALT) levels and risk of type 2 diabetes is well-studied, the effects of slightly increased ALT levels within the normal range on the temporal normal glucose profile remains poorly understood. Methods A total of 322 Chinese subjects without impaired glucose tolerance or previous diagnoses of diabetes were recruited for study from 10 hospitals in urban areas across China. All subjects wore a continuous glucose monitoring (CGM) system for three consecutive days. The diurnal (06∶00–20∶00) and nocturnal (20∶00–06∶00) mean blood glucose (MBG) levels were calculated. Subjects were stratified by ALT quartile level and correlation analyses were performed. Results The median ALT level was 17 IU/L, and subjects with ALT ≥17 IU/L had higher nocturnal MBG level than those with ALT <17 IU/L (P<0.05). Nocturnal MBG was positively correlated with ALT levels (Pearson correlation analysis: r = 0.187, P = 0.001), and the correlation remained significant after correction for the homeostatic model assessment of insulin resistance index (HOMA-IR) (r = 0.105, P = 0.041). No correlations were found between diurnal MBG and ALT, and nocturnal or diurnal MBG and aspartate aminotransferase or gamma-glutamyltransferase (all, P>0.05). Multivariate stepwise regression analysis of elevated nocturnal MBG identified increased HOMA-IR, elevated ALT levels, and decreased homeostatic model assessment of ß-cell function as independent factors (all, P<0.05). Conclusions Mildly elevated ALT levels, within the normal range, are associated with unfavorable nocturnal glucose profiles in Chinese subjects with normal glucose regulation. PMID:23424646

  17. Associations of functional alanine-glyoxylate aminotransferase 2 gene variants with atrial fibrillation and ischemic stroke

    PubMed Central

    Seppälä, Ilkka; Kleber, Marcus E.; Bevan, Steve; Lyytikäinen, Leo-Pekka; Oksala, Niku; Hernesniemi, Jussi A.; Mäkelä, Kari-Matti; Rothwell, Peter M.; Sudlow, Cathie; Dichgans, Martin; Mononen, Nina; Vlachopoulou, Efthymia; Sinisalo, Juha; Delgado, Graciela E.; Laaksonen, Reijo; Koskinen, Tuomas; Scharnagl, Hubert; Kähönen, Mika; Markus, Hugh S.; März, Winfried; Lehtimäki, Terho

    2016-01-01

    Asymmetric and symmetric dimethylarginines (ADMA and SDMA) impair nitric oxide bioavailability and have been implicated in the pathogenesis of atrial fibrillation (AF). Alanine–glyoxylate aminotransferase 2 (AGXT2) is the only enzyme capable of metabolizing both of the dimethylarginines. We hypothesized that two functional AGXT2 missense variants (rs37369, V140I; rs16899974, V498L) are associated with AF and its cardioembolic complications. Association analyses were conducted using 1,834 individulas with AF and 7,159 unaffected individuals from two coronary angiography cohorts and a cohort comprising patients undergoing clinical exercise testing. In coronary angiography patients without structural heart disease, the minor A allele of rs16899974 was associated with any AF (OR = 2.07, 95% CI 1.59-2.68), and with paroxysmal AF (OR = 1.98, 95% CI 1.44–2.74) and chronic AF (OR = 2.03, 95% CI 1.35–3.06) separately. We could not replicate the association with AF in the other two cohorts. However, the A allele of rs16899974 was nominally associated with ischemic stroke risk in the meta-analysis of WTCCC2 ischemic stroke cohorts (3,548 cases, 5,972 controls) and with earlier onset of first-ever ischemic stroke (360 cases) in the cohort of clinical exercise test patients. In conclusion, AGXT2 variations may be involved in the pathogenesis of AF and its age-related thromboembolic complications. PMID:26984639

  18. Hepatocyte nuclear factor 4α transactivates the mitochondrial alanine aminotransferase gene in the kidney of Sparus aurata.

    PubMed

    Salgado, María C; Metón, Isidoro; Anemaet, Ida G; González, J Diego; Fernández, Felipe; Baanante, Isabel V

    2012-02-01

    Alanine aminotransferase (ALT) plays an important role in amino acid metabolism and gluconeogenesis. The preference of carnivorous fish for protein amino acids instead of carbohydrates as a source of energy lead us to study the transcriptional regulation of the mitochondrial ALT (mALT) gene and to characterize the enzyme kinetics and modulation of mALT expression in the kidney of gilthead sea bream (Sparus aurata) under different nutritional and hormonal conditions. 5'-Deletion analysis of mALT promoter in transiently transfected HEK293 cells, site-directed mutagenesis and electrophoretic mobility shift assays allowed us to identify HNF4α as a new factor involved in the transcriptional regulation of mALT expression. Quantitative RT-PCR assays showed that starvation and the administration of streptozotocin (STZ) decreased HNF4α levels in the kidney of S. aurata, leading to the downregulation of mALT transcription. Analysis of the tissue distribution showed that kidney, liver, and intestine were the tissues with higher mALT and HNF4α expression. Kinetic analysis indicates that mALT enzyme is more efficient in catalyzing the conversion of L: -alanine to pyruvate than the reverse reaction. From these results, we conclude that HNF4α transactivates the mALT promoter and that the low levels of mALT expression found in the kidney of starved and STZ-treated fish result from a decreased expression of HNF4α. Our findings suggest that the mALT isoenzyme plays a major role in oxidazing dietary amino acids, and points to ALT as a target for a biotechnological action to spare protein and optimize the use of dietary nutrients for fish culture. PMID:21607544

  19. Relationships between serum asunaprevir concentration and alanine aminotransferase elevation during daclatasvir plus asunaprevir for chronic HCV genotype 1b infection.

    PubMed

    Akuta, Norio; Sezaki, Hitomi; Suzuki, Fumitaka; Kawamura, Yusuke; Hosaka, Tetsuya; Kobayashi, Masahiro; Kobayashi, Mariko; Saitoh, Satoshi; Suzuki, Yoshiyuki; Arase, Yasuji; Ikeda, Kenji; Kumada, Hiromitsu

    2016-03-01

    Alanine aminotransferase (ALT) elevations were the most frequent adverse events during all-oral combinations with daclatasvir and asunaprevir for patients with hepatitis C virus (HCV) infection, but the underline mechanisms are unclear. Seventy patients with chronic HCV genotype 1b infection, who were introduced daclatasvir 60 mg once daily plus asunaprevir 100 mg twice daily for 24 weeks, were measured serum asunaprevir concentrations at the one point or more of 2, 4, and 8 weeks after the start of treatment. In 4 and 8 weeks after the start of treatment, asunaprevir concentrations in patients with albumin levels <3.6 g/dl at baseline were significantly higher than those in patients with albumin levels ≥3.6 g/dl. The baseline factors did not affect to ALT severe elevations (≥300 IU/l). At 2 weeks after the start of treatment, ALT severe elevations with asunaprevir concentrations of ≥800 ng/ml (54.5%) tended to indicate the higher rates than those of <800 ng/ml (17.6%). Furthermore, the discontinuation or reduction of asunaprevir improved ALT levels, regardless the significant decrease of serum asunaprevir concentrations. In conclusion, serum albumin levels affected to serum asunaprevir concentrations, and serum asunaprevir concentrations might partly affect to ALT severe elevations. Further large-scale prospective studies are needed to investigate the impact of the discontinuation or reduction of asunaprevir to help in the design of more effective therapeutic regimens. PMID:26292191

  20. A low-CO2-inducible gene encoding an alanine: alpha-ketoglutarate aminotransferase in Chlamydomonas reinhardtii.

    PubMed Central

    Chen, Z Y; Burow, M D; Mason, C B; Moroney, J V

    1996-01-01

    At low-CO2 (air) conditions, the unicellular green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration. To study this adaptation to low CO2, cDNA clones induced under low-CO2 growth conditions were selected through differential screening. One full-length clone is 2552 bp, with an open reading frame encoding 521 amino acids. The deduced amino acid sequence shows about 50% identity with alanine: alpha-ketogutarate aminotransferase (Ala AT, EC 2.6.1.2) from plants and animals, and the mRNA of this clone increased 4- to 5-fold 4 h after cells were switched from high-CO2 to low-CO2 growth conditions. The expression of the enzyme and its activity also increased accordingly at low-CO2 growth conditions. To study the physiological role of Ala AT, a pyridoxal phosphate inhibitor, aminooxyacetic acid, was added at 40 microM to the growth medium when cells were beginning to adapt to low CO2. This caused a 30% decrease in the maximum photosynthetic rate in air-adapting cells 8 h later. The addition of the inhibitor also caused the cells to excrete glycolate, a photorespiratory intermediate, but did not change the apparent affinity of the cell for external CO2. These physiological studies are consistent with the assumption that Ala AT is involved in the adaptation to low-CO2 conditions. PMID:8883380

  1. A low-CO2-inducible gene encoding an alanine: alpha-ketoglutarate aminotransferase in Chlamydomonas reinhardtii.

    PubMed

    Chen, Z Y; Burow, M D; Mason, C B; Moroney, J V

    1996-10-01

    At low-CO2 (air) conditions, the unicellular green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration. To study this adaptation to low CO2, cDNA clones induced under low-CO2 growth conditions were selected through differential screening. One full-length clone is 2552 bp, with an open reading frame encoding 521 amino acids. The deduced amino acid sequence shows about 50% identity with alanine: alpha-ketogutarate aminotransferase (Ala AT, EC 2.6.1.2) from plants and animals, and the mRNA of this clone increased 4- to 5-fold 4 h after cells were switched from high-CO2 to low-CO2 growth conditions. The expression of the enzyme and its activity also increased accordingly at low-CO2 growth conditions. To study the physiological role of Ala AT, a pyridoxal phosphate inhibitor, aminooxyacetic acid, was added at 40 microM to the growth medium when cells were beginning to adapt to low CO2. This caused a 30% decrease in the maximum photosynthetic rate in air-adapting cells 8 h later. The addition of the inhibitor also caused the cells to excrete glycolate, a photorespiratory intermediate, but did not change the apparent affinity of the cell for external CO2. These physiological studies are consistent with the assumption that Ala AT is involved in the adaptation to low-CO2 conditions. PMID:8883380

  2. Genetic engineering of improved nitrogen use efficiency in rice by the tissue-specific expression of alanine aminotransferase.

    PubMed

    Shrawat, Ashok K; Carroll, Rebecka T; DePauw, Mary; Taylor, Gregory J; Good, Allen G

    2008-09-01

    Summary Nitrogen is quantitatively the most essential nutrient for plants and a major factor limiting crop productivity. One of the critical steps limiting the efficient use of nitrogen is the ability of plants to acquire it from applied fertilizer. Therefore, the development of crop plants that absorb and use nitrogen more efficiently has been a long-term goal of agricultural research. In an attempt to develop nitrogen-efficient plants, rice (Oryza sativa L.) was genetically engineered by introducing a barley AlaAT (alanine aminotransferase) cDNA driven by a rice tissue-specific promoter (OsAnt1). This modification increased the biomass and grain yield significantly in comparison with control plants when plants were well supplied with nitrogen. Compared with controls, transgenic rice plants also demonstrated significant changes in key metabolites and total nitrogen content, indicating increased nitrogen uptake efficiency. The development of crop plants that take up and assimilate nitrogen more efficiently would not only improve the use of nitrogen fertilizers, resulting in lower production costs, but would also have significant environmental benefits. These results are discussed in terms of their relevance to the development of strategies to engineer enhanced nitrogen use efficiency in crop plants. PMID:18510577

  3. Plasma Levels of Alanine Aminotransferase in the First Trimester Identify High Risk Chinese Women for Gestational Diabetes

    PubMed Central

    Leng, Junhong; Zhang, Cuiping; Wang, Peng; Li, Nan; Li, Weiqin; Liu, Huikun; Zhang, Shuang; Hu, Gang; Yu, Zhijie; Ma, Ronald CW; Chan, Juliana CN; Yang, Xilin

    2016-01-01

    Alanine aminotransferase (ALT) predicts type 2 diabetes but it is uncertain whether it also predicts gestational diabetes mellitus (GDM). We recruited 17359 Chinese women with ALT measured in their first trimester. At 24–28 weeks of gestation, all women underwent a 50-gram 1-hour glucose challenge test (GCT) followed by a 75-gram 2-hour oral glucose tolerance test if GCT result was ≥7.8 mmol/L. Restricted cubic spline analysis was used to examine full-range risk associations of ALT levels with GDM. Relative excess risk due to interaction, attributable proportion due to interaction and synergy index were used to estimate additive interaction between high ALT and overweight/obesity for GDM. Finally, 1332 (7.7%) women had GDM. ALT levels were positively associated with GDM risk without a clear threshold. Using ALT levels <22 U/L as the referent, the middle ALT levels (≥22 to <40 U/L) [odds ratio (OR) (95% confidence intervals): 1.41(1.21–1.65)] and high ALT levels (≥40 U/L) [1.62 (1.31–2.00)] were associated with increased GDM risk. Maternal overweight/obesity greatly enhanced the OR of ALT ≥22 U/L from 1.44 (1.23–1.69) to 3.46 (2.79–4.29) with significant additive interactions. In conclusion, elevated ALT levels in the first trimester even within normal range predicted GDM risk, further enhanced by overweight/obesity. PMID:27264612

  4. Effects of alanine:glyoxylate aminotransferase variants and pyridoxine sensitivity on oxalate metabolism in a cell-based cytotoxicity assay.

    PubMed

    Fargue, Sonia; Knight, John; Holmes, Ross P; Rumsby, Gill; Danpure, Christopher J

    2016-06-01

    The hereditary kidney stone disease primary hyperoxaluria type 1 (PH1) is caused by a functional deficiency of the liver-specific, peroxisomal, pyridoxal-phosphate-dependent enzyme, alanine:glyoxylate aminotransferase (AGT). One third of PH1 patients, particularly those expressing the p.[(Pro11Leu; Gly170Arg; Ile340Met)] mutant allele, respond clinically to pharmacological doses of pyridoxine. To gain further insight into the metabolic effects of AGT dysfunction in PH1 and the effect of pyridoxine, we established an "indirect" glycolate cytotoxicity assay using CHO cells expressing glycolate oxidase (GO) and various normal and mutant forms of AGT. In cells expressing GO the great majority of glycolate was converted to oxalate and glyoxylate, with the latter causing the greater decrease in cell survival. Co-expression of normal AGTs and some, but not all, mutant AGT variants partially counteracted this cytotoxicity and led to decreased synthesis of oxalate and glyoxylate. Increasing the extracellular pyridoxine up to 0.3μM led to an increased metabolic effectiveness of normal AGTs and the AGT-Gly170Arg variant. The increased survival seen with AGT-Gly170Arg was paralleled by a 40% decrease in oxalate and glyoxylate levels. These data support the suggestion that the effectiveness of pharmacological doses of pyridoxine results from an improved metabolic effectiveness of AGT; that is the increased rate of transamination of glyoxylate to glycine. The indirect glycolate toxicity assay used in the present study has potential to be used in cell-based drug screening protocols to identify chemotherapeutics that might enhance or decrease the activity and metabolic effectiveness of AGT and GO, respectively, and be useful in the treatment of PH1. PMID:26854734

  5. Plasma Levels of Alanine Aminotransferase in the First Trimester Identify High Risk Chinese Women for Gestational Diabetes.

    PubMed

    Leng, Junhong; Zhang, Cuiping; Wang, Peng; Li, Nan; Li, Weiqin; Liu, Huikun; Zhang, Shuang; Hu, Gang; Yu, Zhijie; Ma, Ronald Cw; Chan, Juliana Cn; Yang, Xilin

    2016-01-01

    Alanine aminotransferase (ALT) predicts type 2 diabetes but it is uncertain whether it also predicts gestational diabetes mellitus (GDM). We recruited 17359 Chinese women with ALT measured in their first trimester. At 24-28 weeks of gestation, all women underwent a 50-gram 1-hour glucose challenge test (GCT) followed by a 75-gram 2-hour oral glucose tolerance test if GCT result was ≥7.8 mmol/L. Restricted cubic spline analysis was used to examine full-range risk associations of ALT levels with GDM. Relative excess risk due to interaction, attributable proportion due to interaction and synergy index were used to estimate additive interaction between high ALT and overweight/obesity for GDM. Finally, 1332 (7.7%) women had GDM. ALT levels were positively associated with GDM risk without a clear threshold. Using ALT levels <22 U/L as the referent, the middle ALT levels (≥22 to <40 U/L) [odds ratio (OR) (95% confidence intervals): 1.41(1.21-1.65)] and high ALT levels (≥40 U/L) [1.62 (1.31-2.00)] were associated with increased GDM risk. Maternal overweight/obesity greatly enhanced the OR of ALT ≥22 U/L from 1.44 (1.23-1.69) to 3.46 (2.79-4.29) with significant additive interactions. In conclusion, elevated ALT levels in the first trimester even within normal range predicted GDM risk, further enhanced by overweight/obesity. PMID:27264612

  6. A Mechanistic Assessment of the Discordance between Normal Serum Alanine Aminotransferase Levels and Altered Liver Histology in Chronic Hepatitis B

    PubMed Central

    Gong, Xianqiong; Yang, Jiaen; Tang, Jinmo; Gu, Chong; Huang, Lijian; Zheng, Ying; Liang, Huiqing; Wang, Min; Wu, Chuncheng; Chen, Yue; Zhang, Manying; Yu, Zhijian; Mao, Qianguo

    2015-01-01

    To understand the mechanisms underlying the discordance between normal serum alanine aminotransferase (ALT) levels and significant alterations in liver histology of chronic hepatitis B virus (HBV) infection with persistent normal ALT (PNALT) or minimally elevated ALT. A total of 300 treatment-naive chronic HBV-infected patients with PNALT (ALT ≤ upper limit of normal [ULN, 40 U/ml]) or minimally elevated ALT (1-2×ULN) were retrospectively enrolled. All patients underwent liver biopsy and histological changes were analyzed along with biochemical and HBV markers. Among 300 participants, 177 were HBeAg-positive and 123 HBeAg-negative. Significant histologic abnormalities were found in 42.9% (76/177) and 52.8% (65/123) of HBeAg-positive and HBeAg-negative patients, respectively. Significant fibrosis, which is a marker of prior injury, was more frequently detected than significant necroinflammation (suggesting active liver injury) in both HBeAg-positive and -negative groups, suggesting that liver injury occurred intermittently in our cohort. No significant differences were noticed in the percentage of patients with severe fibrosis between HBeAg-positive and negative phases or between ages 30 and 40 and over 40, suggesting that the fibrosis was possibly carried over from an early phase. Finally, lowering ALT ULN (30 U/L for men, 19 U/L for women) alone was not adequate to increase the sensitivity of ALT detection of liver injury. However, the study was limited to a small sample size of 13 HBeAg-positive patients with ALT in the revised normal range. We detected significant liver pathology in almost 50% of chronic HBV infected patients with PNALT (ALT ≤ 40 U/ml) or minimally elevated ALT. We postulated that small-scale intermittent liver injury was possibly responsible for the discordance between normal serum ALT and significant liver changes in our cohort. PMID:26230094

  7. ALT (Alanine Aminotransferase) Test

    MedlinePlus

    ... Nausea, vomiting Abdominal swelling and/or pain Jaundice Dark urine, light-colored stool Itching ( pruritus ) ALT may ... sponsored by ... Learn more about ... Understanding Your Tests Inside the Lab In the News Article Index About ...

  8. Assessment of lactate dehydrogenase, alkaline phosphatase and aspartate aminotransferase activities in cow's milk as an indicator of subclinical mastitis.

    PubMed

    Babaei, H; Mansouri-Najand, L; Molaei, M M; Kheradmand, A; Sharifan, M

    2007-05-01

    This study examined the activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in the milk of lactating Holstein cows in association with subclinical mastitis (SCM). A total of 94 milk samples were collected from 58 lactating dairy cows representing stages of lactation from the second to the tenth week after calving. Those which were classified as positive by California mastitis test (CMT) were deemed to have subclinical mastitis. All the milk samples were skimmed by centrifugation at 10 000g at 0 degrees C and were used for enzyme activities estimations. The mean activities of LDH and ALP were higher in the milk from udders with SCM than in the milk from healthy udders (p < 0.05). There were no significant differences in AST values. The maximum agreement rates between the CMT results and LDH and ALP values were seen at thresholds of > 180 IU/L and > 40 IU/L respectively (kappa values 0.65 and 0.79, respectively). However, the sensitivity of the tests for identifying SCM at these thresholds was higher for ALP (96.4%) than for LDH (68.5%). In this study, LDH and ALP tests were standardized for cow's milk and results showed that only the ALP test was reliable in the early diagnosis of subclinical mastitis. PMID:17268916

  9. Elevated Preoperative Serum Alanine Aminotransferase/Aspartate Aminotransferase (ALT/AST) Ratio Is Associated with Better Prognosis in Patients Undergoing Curative Treatment for Gastric Adenocarcinoma

    PubMed Central

    Chen, Shu-Lin; Li, Jian-Pei; Li, Lin-Fang; Zeng, Tao; He, Xia

    2016-01-01

    The level of anine aminotransferase/aspartate aminotransferase (ALT/AST) ratio in the serum was often used to assess liver injury. Whether the ALT/AST ratio (LSR) was associated with prognosis for gastric adenocarcinoma (GA) has not been reported in the literature. Our aim was to investigate the prognostic value of the preoperative LSR in patients with GA. A retrospective study was performed in 231 patients with GA undergoing curative resection. The medical records collected include clinical information and laboratory results. We investigated the correlations between the preoperative LSR and overall survival (OS). Survival analysis was conducted with the Kaplan–Meier method, and Cox regression analysis was used to determine significant independent prognostic factors for predicting survival. A p value of <0.05 was considered to be statistically significant. A total of 231 patients were finally enrolled. The median overall survival was 47 months. Multivariate analysis indicated that preoperative LSR was an independent prognostic factor in GA. Patients with LSR ≤ 0.80 had a greater risk of death than those with LSR > 0.80. The LSR was independently associated with OS in patients with GA (hazard ratio: 0.610; 95% confidence interval: 0.388–0.958; p = 0.032), along with tumor stages (hazard ratio: 3.118; 95% confidence interval: 2.044–4.756; p < 0.001) and distant metastases (hazard ratio: 1.957; 95% confidence interval: 1.119–3.422; p = 0.019). Our study first established a connection between the preoperative LSR and patients undergoing curative resection for GA, suggesting that LSR was a simple, inexpensive, and easily measurable marker as a prognostic factor, and may help to identify high-risk patients for treatment decisions. PMID:27294917

  10. Alanine aminotransferase 1 (OsAlaAT1) plays an essential role in the regulation of starch storage in rice endosperm.

    PubMed

    Yang, Jungil; Kim, Sung-Ryul; Lee, Sang-Kyu; Choi, Heebak; Jeon, Jong-Seong; An, Gynheung

    2015-11-01

    Alteration of storage substances, in particular the major storage form starch, leads to floury endosperm. Because floury mutants have physical attributes for milling processes, identification and characterization of those mutants are valuable. In this study we identified a floury endosperm mutant caused by a T-DNA insertion in Oryza sativa alanine-aminotransferase1 (OsAlaAT1). OsAlaAT1 is localized in the cytosol and has aminotransferase enzyme activity. The osalaat1 mutant has less amylose and its amylopectin is structurally altered. OsAlaAT1 is predominantly expressed in developing seeds during active starch synthesis. AlaAT catalyzes the interconversion of pyruvate to alanine, and this pathway is activated under low-oxygen conditions. Consistently, OsAlaAT1 is induced by such conditions. Expression of the starch synthesis genes AGPases, OsSSI, OsSSIIa, and OsPPDKB is decreased in the mutant. Thus, our observations suggest that OsAlaAT1 plays an essential role in starch synthesis in developing seeds that are exposed to low concentrations of oxygen. PMID:26475189

  11. The enzymology of alanine aminotransferase (AlaAT) isoforms from Hordeum vulgare and other organisms, and the HvAlaAT crystal structure.

    PubMed

    Duff, Stephen M G; Rydel, Timothy J; McClerren, Amanda L; Zhang, Wenlan; Li, Jimmy Y; Sturman, Eric J; Halls, Coralie; Chen, Songyang; Zeng, Jiamin; Peng, Jiexin; Kretzler, Crystal N; Evdokimov, Artem

    2012-12-01

    In this paper we describe the expression, purification, kinetics and biophysical characterization of alanine aminotransferase (AlaAT) from the barley plant (Hordeum vulgare). This dimeric PLP-dependent enzyme is a pivotal element of several key metabolic pathways from nitrogen assimilation to carbon metabolism, and its introduction into transgenic plants results in increased yield. The enzyme exhibits a bi-bi ping-pong reaction mechanism with a K(m) for alanine, 2-oxoglutarate, glutamate and pyruvate of 3.8, 0.3, 0.8 and 0.2 mM, respectively. Barley AlaAT catalyzes the forward (alanine-forming) reaction with a k(cat) of 25.6 s(-1), the reverse (glutamate-forming) reaction with k(cat) of 12.1 s(-1) and an equilibrium constant of ~0.5. The enzyme is also able to utilize aspartate and oxaloacetate with ~10% efficiency as compared to the native substrates, which makes it much more specific than related bacterial/archaeal enzymes (that also have lower K(m) values). We have crystallized barley AlaAT in complex with PLP and l-cycloserine and solved the structure of this complex at 2.7 Å resolution. This is the first example of a plant AlaAT structure, and it reveals a canonical aminotransferase fold similar to structures of the Thermotoga maritima, Pyrococcus furiosus, and human enzymes. This structure bridges our structural understanding of AlaAT mechanism between three kingdoms of life and allows us to shed some light on the specifics of the catalysis performed by these proteins. PMID:22750542

  12. A chemically modified carbon paste electrode with d-lactate dehydrogenase and alanine aminotranferase enzyme sequences for d-lactic acid analysis.

    PubMed

    Shu, H C; Wu, N P

    2001-04-12

    An amperometric biosensor was constructed for the analysis of d-lactic acid based on immobilizing d-lactate dehydrogenase(d-LDH), alanine aminotransferase (ALT), NAD(+), a redox polymer and polyethylenimine in carbon paste. The effect of addition of ALT in the paste, using enzyme sequences of ALT/d-LDH, was insignificant for d-lactic acid analysis. The responses of d-lactic acid in ALT/d-LDH paste electrode are the same as those in d-LDH paste electrode. However, the interference effect of pyruvate in the sample can be substantially reduced if sodium glutamate was applied in the carrier solution. When ALT immobilized in control porous glass as an immobilized enzyme reactor (IMER) was mounted in flow injection analysis system with the d-LDH paste electrode as detector for d-lactate analysis, the interference of the pyruvate can be significantly eliminated. The adverse effect of pyruvate in the samples for d-lactic acid analysis was reduced more effectively in ALT IMER with d-LDH electrode than in ALT/d-LDH electrode. PMID:18968259

  13. Streptomyces beta-alanine:alpha-ketoglutarate aminotransferase, a novel omega-amino acid transaminase. Purification, crystallization, and enzymologic properties.

    PubMed

    Yonaha, K; Suzuki, K; Toyama, S

    1985-03-25

    An enzyme which catalyzes the transamination of beta-alanine with alpha-ketoglutarate was purified to homogeneity from Streptomyces griseus IFO 3102 and crystallized. Molecular weight of the enzyme was found to be 185,000 +/- 10,000 by a gel-filtration method. The enzyme consists of four subunits identical in molecular weight (51,000 +/- 1,000). The transaminase is composed of 483 amino acids/subunit containing 7 and 8 residues of half-cystine and methionine, respectively. The enzyme exhibits absorption maxima at 278 and 415 nm. The pyridoxal 5'-phosphate content was determined to be 4 mol/mol of enzyme. The enzyme catalyzes transamination of omega-amino acids including taurine and hypotaurine. beta-Alanine and DL-beta-aminoisobutyrate served as a good amino donor; the Michaelis constants are 8.0 and 12.5 mM, respectively. alpha-Ketoglutarate is the only amino acceptor (Km = 4.0 mM); pyruvate and oxalacetate are inactive. Based on the substrate specificity, the terminology of beta-alanine:alpha-ketoglutarate transaminase is proposed for the enzyme. Carbonyl reagents, HgCl2,DL-gabaculine, and alpha-fluoro-beta-alanine strongly inhibited the enzyme. PMID:3972825

  14. Mechanisms by which dichloroacetate lowers lactic acid levels: the kinetic interrelationships between lactate, pyruvate, alanine, and glucose.

    PubMed

    Jahoor, F; Zhang, X J; Frazer, E

    1994-01-01

    Dichloroacetate (DCA) is gaining use as an alternative to bicarbonate therapy in the treatment of lactic acidosis. To determine the mechanism(s) by which DCA lowers blood lactate levels, we studied its effect on the kinetic interrelationships between pyruvate, lactate, alanine, and glucose in the hindlimb of dogs during hormonal stimulation of pyruvate production (Ra) and its conversion to lactate. Three groups of dogs (n = 6) were infused with 1-13C-pyruvate to measure whole body pyruvate Ra, and pyruvate Ra and utilization (Rd) across the hindlimb during either a 4-hr infusion of saline (controls), or somatostatin, glucagon, and epinephrine (SGE), or SGE plus dichloroacetate (SGE + DCA). Pyruvate Ra was used as an index of rate of glycolysis and Rd as an index of pyruvate oxidation. In the controls, all kinetic parameters were constant during the saline infusion. Hindlimb pyruvate Ra and Rd were almost equal, and lactate release negligible. Compared to controls, SGE administration significantly increased (P < 0.05) wholebody pyruvate Ra (48.5 +/- 6.2 vs 33.6 +/- 2.4 mumol/kg/min) and blood lactate levels (P < 0.05). Hindlimb pyruvate Ra increased by approximately 150%, but Rd remained unchanged resulting in marked increases in lactate and alanine effluxes. Adding DCA to the SGE infusion significantly reduced wholebody pyruvate Ra (P < 0.05) and blood lactate levels (P < 0.01). In the hindlimb, however, there was no decrease in lactate output, despite a 91% increase in pyruvate utilization because pyruvate Ra also increased. These results suggest that during stimulation of rate of glycolysis, DCA lowers lactate levels by reducing the overall availability of pyruvate for lactate synthesis. This is accomplished by suppressing the rate of glycolysis in tissues other than skeletal muscle and stimulating pyruvate oxidation. PMID:7906882

  15. Relationship Between Alcohol Drinking and Aspartate Aminotransferase:Alanine Aminotransferase (AST:ALT) Ratio, Mean Corpuscular Volume (MCV), Gamma-Glutamyl Transpeptidase (GGT), and Apolipoprotein A1 and B in the U.S. Population*

    PubMed Central

    Liangpunsakul, Suthat; Qi, Rong; Crabb, David W.; Witzmann, Frank

    2010-01-01

    Objective: The misuse of alcohol, even at levels just above two drinks per day, is a public health problem, but identifying patients with this potentially unhealthy drinking is hindered by the lack of tests. Several blood tests, such as those testing for gamma-glutamyl transpeptidase (GGT) or mean corpuscular volume (MCV), are among the commonly used markers to identify very heavy drinking, but combinations of these markers have rarely been tested in lighter drinkers. We examined the relationship between alcohol drinking and the levels of these markers in a national population-based study composed primarily of lighter drinkers. Method: Data were analyzed from 8,708 adult participants in the third U.S. National Health and Nutrition Examination Survey after excluding subjects with iron overload; with hepatitis B and C; who were pregnant; and who were taking prescription drugs such as phenytoin (Dilantin), barbiturates, and hydroxyurea (Droxia and Hydrea). The relationship between the amount of alcohol drinking and GGT, aspartate aminotransferase:alanine aminotransferase ratio, MCV of erythrocytes, and apolipoprotein A1 and B were analyzed and adjusted for potential liver injury risk factors. Results: The prevalence of unhealthy alcohol drinking (defined as consumption of more than two standard drinks per day) was 6.7%. Heavier drinkers tended to be younger and reported an average of 4.2 drinks per day. When tested alone or in combination, the sensitivity and positive predictive values for these blood tests were too low to be clinically useful in identifying the subjects in the heavier drinking category. Conclusions: In this large, national, population-based study, the markers of heavy drinking studied here, either alone or in combination, did not appear to be useful in identifying unhealthy drinking. More work is needed to find the novel marker(s) associated with risky alcohol drinking. PMID:20230722

  16. Relationship of creatine kinase, aspartate aminotransferase, lactate dehydrogenase, and proteinuria to cardiomyopathy in the owl monkey (Aotus vociferans)

    SciTech Connect

    Gozalo, Alfonso S.; Chavera, Alfonso; Montoya, Enrique J.; Takano, Juan; Weller, Richard E.

    2008-02-01

    The purpose of this study was to determine serum reference values for crea- tine kinase (CK), aspartate aminotransferase (AST), and lactate dehydroge- nase (LDH) in captive-born and wild-caught owl monkeys to assess their usefulness for diagnosing myocardial disease. Urine samples were also collected and semi-quantitative tests performed. There was no statistically significant difference between CK, AST, and LDH when comparing both groups. However, when comparing monkeys with proteinuria to those without proteinuria, a statistically significant difference in CK value was observed (P = 0.021). In addition, the CK/AST ratio revealed that 29% of the animals included in this study had values suggesting cardiac infarction. Grossly, cardiac concentric hypertrophy of the left ventricle and small, pitted kidneys were the most common findings. Microscopically, myocardial fibrosis, contraction band necrosis, hypertrophy and hyperplasia of coronary arteries, medium-sized renal arteries, and afferent glomerular arteriolae were the most significant lesions, along with increased mesangial matrix and hypercellularity of glomeruli, Bowman’s capsule, and peritubular space fibroplasia. These findings suggest that CK, AST, and LDH along with urinalysis provide a reliable method for diagnosing cardiomyopathies in the owl monkey. In addition, CK/AST ratio, proteinuria, and the observed histological and ultrastructural changes suggest that Aotus vociferans suffer from arterial hypertension and chronic myocardial infarction.

  17. Alanine-glyoxylate aminotransferase-deficient mice, a model for primary hyperoxaluria that responds to adenoviral gene transfer.

    PubMed

    Salido, Eduardo C; Li, Xiao M; Lu, Yang; Wang, Xia; Santana, Alfredo; Roy-Chowdhury, Namita; Torres, Armando; Shapiro, Larry J; Roy-Chowdhury, Jayanta

    2006-11-28

    Mutations in the alanine-glyoxylate amino transferase gene (AGXT) are responsible for primary hyperoxaluria type I, a rare disease characterized by excessive hepatic oxalate production that leads to renal failure. We generated a null mutant mouse by targeted mutagenesis of the homologous gene, Agxt, in embryonic stem cells. Mutant mice developed normally, and they exhibited hyperoxaluria and crystalluria. Approximately half of the male mice in mixed genetic background developed calcium oxalate urinary stones. Severe nephrocalcinosis and renal failure developed after enhancement of oxalate production by ethylene glycol administration. Hepatic expression of human AGT1, the protein encoded by AGXT, by adenoviral vector-mediated gene transfer in Agxt(-/-) mice normalized urinary oxalate excretion and prevented oxalate crystalluria. Subcellular fractionation and immunofluorescence studies revealed that, as in the human liver, the expressed wild-type human AGT1 was predominantly localized in mouse hepatocellular peroxisomes, whereas the most common mutant form of AGT1 (G170R) was localized predominantly in the mitochondria. PMID:17110443

  18. Risk factors associated with hepatitis B or C markers or elevated alanine aminotransferase level among blood donors on a tropical island: the Guadeloupe experience.

    PubMed

    Fest, T; Viel, J F; Agis, F; Coffe, C; Dupond, J L; Hervé, P

    1992-10-01

    Donated blood is currently screened for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), antibody to hepatitis C virus (anti-HCV), and alanine aminotransferase (ALT) levels to prevent posttransfusion hepatitis. A prospective study of 2368 blood donors was carried out in Guadeloupe (French West Indies) with a view to determining the risk factors associated with serologic abnormalities. Blood donors included in the study had to complete a questionnaire. Statistical analysis was performed on the data thus obtained: 571 donations (24%) were positive for at least one of the four analyzed markers. The results were that 3.2 percent were positive for HBsAg, 22 percent for anti-HBc, and 0.8 percent for anti-HCV, and 1.4 percent had ALT > or = 45 IU per L. A good correlation was found between anti-HCV and elevated ALT. Transfusion history and two socioeconomic categories (working class, military personnel) were found to be risk factors. Other risk factors were lifelong residence in Guadeloupe (with risk increasing with the number of years), birthplace and current residence in the southern part of the island, and the existence of gastrointestinal discomfort unrelated to viral hepatitis (odds ratio = 2.98). The results of this study illustrate the difficulty of implementing a preventive policy against posttransfusion hepatitis in a tropical area. The unique epidemiologic situation of Guadeloupe as regards hepatitis B virus has led to more restrictive criteria for the acceptance of blood donors. PMID:1412685

  19. Comparison of measurements of canine plasma creatinine, glucose, proteins, urea, alanine aminotransferase, and alkaline phosphatase obtained with Spotchem SP 4430 and Vitros 250 analyzers.

    PubMed

    Trumel, C; Diquélou, A; Germain, C; Palanché, F; Braun, J P

    2005-12-01

    The suitability of the Spotchem 4430 benchtop biochemistry analyzer for canine blood samples was tested for creatinine, glucose, proteins, urea, alkaline phosphatases and alanine aminotransferase. Results obtained from whole blood and corresponding heparin plasma were identical except for proteins which were higher in plasma (n=10). Between series imprecision (n=10) was <5% for substrates and <10% for enzymes. Comparison of results from 100 Li-heparin samples with those measured with a Vitros 250 analyzer showed good correlation (r>0.93). The slopes of the Passing-Bablock's regression ranged from 0.90 to 1.20 and intercepts were low. The mean biases were low, except for creatinine for which the results obtained by Spotchem (Jaffe reaction) were about 20 micromol/L higher than with the Vitros (enzymatic reaction). The results of this study show that the Spotchem analyzer is suitable for use in canine whole blood or plasma when small numbers of tests are to be performed and large analyzers are not available. PMID:16054888

  20. Plasma glutathione S-transferase and F protein are more sensitive than alanine aminotransferase as markers of paracetamol (acetaminophen)-induced liver damage.

    PubMed

    Beckett, G J; Foster, G R; Hussey, A J; Oliveira, D B; Donovan, J W; Prescott, L F; Proudfoot, A T

    1989-11-01

    Concentrations of glutathione S-transferase (GST; glutathione transferase; EC 2.5.1.18) B1 subunits, F protein, and the activity of alanine aminotransferase (ALT; EC 2.6.1.2) were measured in sequential plasma samples taken from nine patients with self-administered paracetamol (acetaminophen) poisoning. GST exceeded the reference interval in all patients at the time of admission, and F protein was increased in seven. In contrast, abnormal activities of ALT in plasma were found in only one of the nine on admission, a patient admitted 12 h after poisoning. Subsequent to admission nine, eight, and five patients, respectively, had abnormal concentrations of GST, F protein, and ALT. When expressed as multiples of the upper reference limit, the highest values for GST measured in each patient always far exceeded the greatest abnormalities in ALT; this was true for F protein in only five patients. Patients in whom the concentration of GST exceeded 10 micrograms/L on admission subsequently went on to develop moderate or severe liver damage, despite treatment with N-acetylcysteine. F protein and ALT measurements on admission were not as efficient as GST at predicting the clinical outcome of the patients. We conclude that GST and F protein offer clear advantages over ALT for detecting minor degrees of acute liver dysfunction, particularly when only centrilobular damage may be involved. PMID:2582614

  1. NMR studies of protonation and hydrogen bond states of internal aldimines of pyridoxal 5'-phosphate acid-base in alanine racemase, aspartate aminotransferase, and poly-L-lysine.

    PubMed

    Chan-Huot, Monique; Dos, Alexandra; Zander, Reinhard; Sharif, Shasad; Tolstoy, Peter M; Compton, Shara; Fogle, Emily; Toney, Michael D; Shenderovich, Ilya; Denisov, Gleb S; Limbach, Hans-Heinrich

    2013-12-01

    Using (15)N solid-state NMR, we have studied protonation and H-bonded states of the cofactor pyridoxal 5'-phosphate (PLP) linked as an internal aldimine in alanine racemase (AlaR), aspartate aminotransferase (AspAT), and poly-L-lysine. Protonation of the pyridine nitrogen of PLP and the coupled proton transfer from the phenolic oxygen (enolimine form) to the aldimine nitrogen (ketoenamine form) is often considered to be a prerequisite to the initial step (transimination) of the enzyme-catalyzed reaction. Indeed, using (15)N NMR and H-bond correlations in AspAT, we observe a strong aspartate-pyridine nitrogen H-bond with H located on nitrogen. After hydration, this hydrogen bond is maintained. By contrast, in the case of solid lyophilized AlaR, we find that the pyridine nitrogen is neither protonated nor hydrogen bonded to the proximal arginine side chain. However, hydration establishes a weak hydrogen bond to pyridine. To clarify how AlaR is activated, we performed (13)C and (15)N solid-state NMR experiments on isotopically labeled PLP aldimines formed by lyophilization with poly-L-lysine. In the dry solid, only the enolimine tautomer is observed. However, a fast reversible proton transfer involving the ketoenamine tautomer is observed after treatment with either gaseous water or gaseous dry HCl. Hydrolysis requires the action of both water and HCl. The formation of an external aldimine with aspartic acid at pH 9 also produces the ketoenamine form stabilized by interaction with a second aspartic acid, probably via a H-bond to the phenolic oxygen. We postulate that O-protonation is an effectual mechanism for the activation of PLP, as is N-protonation, and that enzymes that are incapable of N-protonation employ this mechanism. PMID:24147985

  2. Reconstituted high-density lipoprotein can elevate plasma alanine aminotransferase by transient depletion of hepatic cholesterol: role of the phospholipid component.

    PubMed

    Herzog, Eva; Pragst, Ingo; Waelchli, Marcel; Gille, Andreas; Schenk, Sabrina; Mueller-Cohrs, Jochen; Diditchenko, Svetlana; Zanoni, Paolo; Cuchel, Marina; Seubert, Andreas; Rader, Daniel J; Wright, Samuel D

    2016-08-01

    Human apolipoprotein A-I preparations reconstituted with phospholipids (reconstituted high-density lipoprotein [HDL]) have been used in a large number of animal and human studies to investigate the physiological role of apolipoprotein A-I. Several of these studies observed that intravenous infusion of reconstituted HDL might cause transient elevations in plasma levels of hepatic enzymes. Here we describe the mechanism of this enzyme release. Observations from several animal models and in vitro studies suggest that the extent of hepatic transaminase release (alanine aminotransferase [ALT]) correlates with the movement of hepatic cholesterol into the blood after infusion. Both the amount of ALT release and cholesterol movement were dependent on the amount and type of phospholipid present in the reconstituted HDL. As cholesterol is known to dissolve readily in phospholipid, an HDL preparation was loaded with cholesterol before infusion into rats to assess the role of diffusion of cholesterol out of the liver and into the reconstituted HDL. Cholesterol-loaded HDL failed to withdraw cholesterol from tissues and subsequently failed to cause ALT release. To investigate further the role of cholesterol diffusion, we employed mice deficient in SR-BI, a transporter that facilitates spontaneous movement of cholesterol between cell membranes and HDL. These mice showed substantially lower movement of cholesterol into the blood and markedly lower ALT release. We conclude that initial depletion of hepatic cholesterol initiates transient ALT release in response to infusion of reconstituted HDL. This effect may be controlled by appropriate choice of the type and amount of phospholipid in reconstituted HDL. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26651060

  3. Interferon sensitivity-determining region of nonstructural region 5A of hepatitis C virus genotype 1b correlates with serum alanine aminotransferase levels in chronic infection.

    PubMed

    Yoshioka, K; Ito, H; Watanabe, K; Yano, M; Ishigami, M; Mizutani, T; Sasaki, Y; Goto, H

    2005-03-01

    The mutations in the interferon (IFN) sensitivity-determining region (ISDR) of nonstructural region 5A (NS5A) of hepatitis C virus (HCV) have been correlated with response to IFN therapy. NS5A appears to disrupt a host antiviral pathway that plays a role in suppressing virus replication and protects hepatocytes from apoptosis. We assessed whether ISDR correlates with viral load and serum alanine aminotransferase (ALT) levels. Serum viral load and ALT levels were prospectively measured bimonthly by HCV core protein assay and monthly, respectively, for 22 months in 87 patients chronically infected with HCV genotype 1b. ISDR of HCV was directly sequenced from the products of reverse transcription and polymerase chain reaction of HCV RNA. Five patients had four or more substitutions (mutant type), 33 had 1-3 (intermediate type), and 49 had no substitutions (wild type) in ISDR. The numbers of substitutions in ISDR were inversely correlated with mean viral load over a 22-month period (r = 0.292, P = 0.0060) and directly with mean serum ALT levels (r = 0.360, P = 0.0006). The numbers of substitutions in ISDR was significantly larger in the patients with changes of viral load more than fivefold during the 22 months (1.4 +/- 2.4) than in those without changes (0.6 +/- 0.8) (P = 0.0188). The present study demonstrates that the patients with more substitutions in ISDR had significantly higher serum ALT levels and smaller viral load. These results suggest that NS5A with more substitutions in ISDR may lose the ability to block host antiviral pathways and to protect hepatocytes from apoptosis. PMID:15720528

  4. Primary hyperoxaluria type 1 in the Canary Islands: a conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase.

    PubMed

    Santana, A; Salido, E; Torres, A; Shapiro, L J

    2003-06-10

    Primary hyperoxaluria type 1 (PH1) is an inborn error of metabolism resulting from a deficiency of alanine:glyoxylate aminotransferase (AGXT; EC 2.6.1.44). Most of the PH1 alleles detected in the Canary Islands carry the Ile-244 --> Thr (I244T) mutation in the AGXT gene, with 14 of 16 patients homozygous for this mutation. Four polymorphisms within AGXT and regional microsatellites also were shared in their haplotypes (AGXT*LTM), consistent with a founder effect. The consequences of these amino acid changes were investigated. Although I244T alone did not affect AGXT activity or subcellular localization, when present in the same protein molecule as Leu-11 --> Pro (L11P), it resulted in loss of enzymatic activity in soluble cell extracts. Like its normal counterpart, the AGXT*LTM protein was present in the peroxisomes but it was insoluble in detergent-free buffers. The polymorphism L11P behaved as an intragenic modifier of the I244T mutation, with the resulting protein undergoing stable interaction with molecular chaperones and aggregation. This aggregation was temperature-sensitive. AGXT*LTM expressed in Escherichia coli, as a GST-fusion protein, and in insect cells could be purified and retained enzymatic activity. Among various chemical chaperones tested in cell culture, betaine substantially improved the solubility of the mutant protein and the enzymatic activity in cell lysates. In summary, I244T, the second most common mutation responsible for PH1, is a protein conformational disease that may benefit from new therapies with pharmacological chaperones or small molecules to minimize protein aggregation. PMID:12777626

  5. High serum carotenoids are associated with lower risk for developing elevated serum alanine aminotransferase among Japanese subjects: the Mikkabi cohort study.

    PubMed

    Sugiura, Minoru; Nakamura, Mieko; Ogawa, Kazunori; Ikoma, Yoshinori; Yano, Masamichi

    2016-04-01

    Many recent studies have shown that antioxidant vitamins and/or carotenoids may reduce liver disease, but this association has not been well established with thorough longitudinal cohort studies. The objective of this study was to longitudinally investigate whether serum carotenoids at baseline are associated with the risk of developing elevated serum alanine aminotransferase (ALT) among Japanese subjects. We conducted a follow-up study of 1073 males and females aged between 30 and 79 years at baseline from the Mikkabi prospective cohort study. Those who participated in the baseline study and completed follow-up surveys were examined longitudinally. Exclusions included excessive alcohol consumption (≥60 g alcohol/d), hepatitis B and C and having a history of medication use for liver disease. A cohort of 213 males and 574 females free of elevated serum ALT (>30 IU/ml) at baseline was studied. Over a mean follow-up period of 7·4 (sd 3·1) years, thirty-one males and forty-nine females developed new elevated serum ALT. After adjustments for confounders, the hazard ratios for elevated serum ALT in the highest tertiles of basal serum β-carotene, β-cryptoxanthin and total provitamin A carotenoids against the lowest tertiles were 0·43 (95 % CI 0·22, 0·81), 0·51 (CI 0·27, 0·94) and 0·52 (CI 0·28, 0·97), respectively. For α-carotene and lycopene, borderline reduced risks were also observed; however, these were not significant. Our results further support the hypothesis that antioxidant carotenoids, especially provitamin A carotenoids, might help prevent earlier pathogenesis of non-alcoholic liver disease in Japanese subjects. PMID:26916997

  6. Knockdown of a putative alanine aminotransferase gene affects amino acid content and flight capacity in the Colorado potato beetle Leptinotarsa decemlineata.

    PubMed

    Wan, Pin-Jun; Fu, Kai-Yun; Lü, Feng-Gong; Guo, Wen-Chao; Li, Guo-Qing

    2015-07-01

    Alanine aminotransferase (ALT) plays important physiological and biochemical roles in insect. In this study, a full-length Ldalt cDNA was cloned from Leptinotarsa decemlineata. It was ubiquitously expressed in the eggs, larvae, pupae and adults. In the adults, Ldalt mRNA was widely distributed in thorax muscles, fat body, midgut, foregut, hindgut, Malpighian tubules, ventral ganglion and epidermis, with the expression levels from the highest to the lowest. Two double-stranded RNAs (dsRNAs) (dsLdalt1 and dsLdalt2) targeting Ldalt were constructed and bacterially expressed. After adults fed on dsLdalt1- and dsLdalt2-immersed foliage for 3 day, Ldalt mRNA abundance was significantly decreased by 79.5 and 71.1 %, and ALT activities were significantly reduced by 64.5 and 67.6 %, respectively. Moreover, silencing Ldalt affected free amino acid contents. Lysine was decreased by 100.0 and 100.0 %, and arginine was reduced by 87.5 and 89.4 %, respectively, in the hemolymph from dsLdalt1- and dsLdalt2-ingested beetles, compared with control ones. In contrast, proline was increased by 88.7 and 96.4 %. Furthermore, ingestion of dsLdalt1 and dsLdalt2 significantly decreased flight speed, shortened flight duration time and flight distance. In addition, knocking down Ldalt significantly increased adult mortality. These data imply that LdALT plays important roles in amino acid metabolism and in flight in L. decemlineata. PMID:25868655

  7. Primary hyperoxaluria type 1 in the Canary Islands: A conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase

    PubMed Central

    Santana, A.; Salido, E.; Torres, A.; Shapiro, L. J.

    2003-01-01

    Primary hyperoxaluria type 1 (PH1) is an inborn error of metabolism resulting from a deficiency of alanine:glyoxylate aminotransferase (AGXT; EC 2.6.1.44). Most of the PH1 alleles detected in the Canary Islands carry the Ile-244 → Thr (I244T) mutation in the AGXT gene, with 14 of 16 patients homozygous for this mutation. Four polymorphisms within AGXT and regional microsatellites also were shared in their haplotypes (AGXT*LTM), consistent with a founder effect. The consequences of these amino acid changes were investigated. Although I244T alone did not affect AGXT activity or subcellular localization, when present in the same protein molecule as Leu-11 → Pro (L11P), it resulted in loss of enzymatic activity in soluble cell extracts. Like its normal counterpart, the AGXT*LTM protein was present in the peroxisomes but it was insoluble in detergent-free buffers. The polymorphism L11P behaved as an intragenic modifier of the I244T mutation, with the resulting protein undergoing stable interaction with molecular chaperones and aggregation. This aggregation was temperature-sensitive. AGXT*LTM expressed in Escherichia coli, as a GST-fusion protein, and in insect cells could be purified and retained enzymatic activity. Among various chemical chaperones tested in cell culture, betaine substantially improved the solubility of the mutant protein and the enzymatic activity in cell lysates. In summary, I244T, the second most common mutation responsible for PH1, is a protein conformational disease that may benefit from new therapies with pharmacological chaperones or small molecules to minimize protein aggregation. PMID:12777626

  8. Pyridoxamine and pyridoxal are more effective than pyridoxine in rescuing folding-defective variants of human alanine:glyoxylate aminotransferase causing primary hyperoxaluria type I.

    PubMed

    Oppici, Elisa; Fargue, Sonia; Reid, Emma S; Mills, Philippa B; Clayton, Peter T; Danpure, Christopher J; Cellini, Barbara

    2015-10-01

    Vitamin B6 in the form of pyridoxine (PN) is one of the most widespread pharmacological therapies for inherited diseases involving pyridoxal phosphate (PLP)-dependent enzymes, including primary hyperoxaluria type I (PH1). PH1 is caused by a deficiency of liver-peroxisomal alanine: glyoxylate aminotransferase (AGT), which allows glyoxylate oxidation to oxalate leading to the deposition of insoluble calcium oxalate in the kidney. Only a minority of PH1 patients, mostly bearing the F152I and G170R mutations, respond to PN, the only pharmacological treatment currently available. Moreover, excessive doses of PN reduce the specific activity of AGT in a PH1 cellular model. Nevertheless, the possible effect(s) of other B6 vitamers has not been investigated previously. Here, we compared the ability of PN in rescuing the effects of the F152I and G170R mutations with that of pyridoxamine (PM) and PL. We found that supplementation with PN raises the intracellular concentration of PN phosphate (PNP), which competes with PLP for apoenzyme binding leading to the formation of an inactive AGT-PNP complex. In contrast, PNP does not accumulate in the cell upon PM or PL supplementation, but higher levels of PLP and PM phosphate (PMP), the two active forms of the AGT coenzyme, are found. This leads to an increased ability of PM and PL to rescue the effects of the F152I and G170R mutations compared with PN. A similar effect was also observed for other folding-defective AGT variants. Thus, PM and PL should be investigated as matter of importance as therapeutics for PH1 patients bearing folding mutations. PMID:26199318

  9. Misfolding caused by the pathogenic mutation G47R on the minor allele of alanine:glyoxylate aminotransferase and chaperoning activity of pyridoxine.

    PubMed

    Montioli, Riccardo; Oppici, Elisa; Dindo, Mirco; Roncador, Alessandro; Gotte, Giovanni; Cellini, Barbara; Borri Voltattorni, Carla

    2015-10-01

    Liver peroxisomal alanine:glyoxylate aminotransferase (AGT), a pyridoxal 5'-phosphate (PLP) enzyme, exists as two polymorphic forms, the major (AGT-Ma) and the minor (AGT-Mi) haplotype. Deficit of AGT causes Primary Hyperoxaluria Type 1 (PH1), an autosomal recessive rare disease. Although ~one-third of the 79 disease-causing missense mutations segregates on AGT-Mi, only few of them are well characterized. Here for the first time the molecular and cellular defects of G47R-Mi are reported. When expressed in Escherichia coli, the recombinant purified G47R-Mi variant exhibits only a 2.5-fold reduction of its kcat, and its apo form displays a remarkably decreased PLP binding affinity, increased dimer-monomer equilibrium dissociation constant value, susceptibility to thermal denaturation and to N-terminal region proteolytic cleavage, and aggregation propensity. When stably expressed in a mammalian cell line, we found ~95% of the intact form of the variant in the insoluble fraction, and proteolyzed (within the N-terminal region) and aggregated forms both in the soluble and insoluble fractions. Moreover, the intact and nicked forms have a peroxisomal and a mitochondrial localization, respectively. Unlike what already seen for G41R-Mi, exposure of G47R-Mi expressing cells to pyridoxine (PN) remarkably increases the expression level and the specific activity in a dose-dependent manner, reroutes all the protein to peroxisomes, and rescues its functionality. Although the mechanism of the different effect of PN on the variants G47R-Mi and G41R-Mi remains elusive, the chaperoning activity of PN may be of value in the therapy of patients bearing the G47R mutation. PMID:26149463

  10. Higher Ratio of Serum Alpha-Fetoprotein Could Predict Outcomes in Patients with Hepatitis B Virus-Associated Hepatocellular Carcinoma and Normal Alanine Aminotransferase

    PubMed Central

    Park, Joong-Won

    2016-01-01

    Background The role of serum alpha-fetoprotein (AFP) levels in the surveillance and diagnosis of hepatocellular carcinoma (HCC) is controversial. The aim of this study was to investigate the value of serially measured serum AFP levels in HCC progression or recurrence after initial treatment. Methods A total of 722 consecutive patients newly diagnosed with HCC and treated at the National Cancer Center, Korea, between January 2004 and December 2009 were enrolled. The AFP ratios between 4–8 weeks post-treatment and those at the time of HCC progression or recurrence were obtained. Multivariate logistic regression analysis was performed to correlate the post-treatment AFP ratios with the presence of HCC progression or recurrence. Results The etiology of HCC was related to chronic hepatitis B virus (HBV) infection in 562 patients (77.8%), chronic hepatitis C virus (HCV) infection in 74 (10.2%), and non-viral cause in 86 (11.9%). There was a significant decrease in serum AFP levels from the baseline to 4 to 8 weeks after treatment (median AFP, 319.6 ng/mL vs. 49.6 ng/mL; p< 0.001). Multivariate analysis showed that an AFP ratio > 1.0 was an independently associated with HCC progression or recurrence. Among the different causes of HCC analyzed, this association was significant only for HCC related to chronic hepatitis B (p< 0.001) and non-viral causes (p<0.05), and limited only to patients who had normal alanine aminotransferase (ALT) levels. Conclusion Serial measurements of serum AFP ratios could be helpful in detecting progression or recurrence in treated patients with HBV-HCC and normal ALT. PMID:27304617

  11. Enzymological and mutational analysis of a complex primary hyperoxaluria type I phenotype involving alanine: Glyoxylate aminotransferase peroxisome-to-mitochondrion mistargeting and intraperoxisomal aggregation

    SciTech Connect

    Danpure, C.J.; Purdue, P.E.; Allsop, J.; Lumb, M.J.; Jennings, P.R. ); Scheinman, J.I. ); Mauer, S.M. ); Davidson, N.O. )

    1993-08-01

    Primary hyperoxaluri type 1 (PH1) is a rare autosomal recessive disease caused by a deficiency of the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). Three unrelated PH1 patients, who possess a novel complex phenotype, are described. At the enzymological level, this phenotype is characterized by a complete, or nearly complete, absence of AGT catalytic activity and reduced AGT immunoreactivity. Unlike normal individuals in whom the AGT is confined to the peroxisomal matrix, the immunoreactive AGT in these three patients was distributed approximately equally between the peroxisomes and mitochondria. The peroxisomal AGT appeared to be aggregated into amorphous core-like structures in which no other peroxisomal enzymes could be identified. Mutational analysis of the AGT gene showed that two of the three patients were compound heterozygotes for two previously unrecognized point mutations which caused Gly41[yields]Arg and Phe152[yields]Iso amino acid substitutions. The third patient was shown to be a compound heterozygote for the Gly41[yields]Arg mutation and a previously recognized Gly170[yields]Arg mutation. All three patients were homozygous for the Pro11[yields]Leu polymorphism that had been found previously with a high allelic frequency in normal populations. It is suggested the the Phe152[yields]Iso and Gly170[yields]Arg substitutions, which are only eighteen residues apart and located in the same highly conserved internal region of 58 amino acids, might be involved in the inhibition of peroxisomal targeting and/or import of AGT and, in combination with the Pro11[yields]Leu polymorphism, be responsible for its aberrant mitochondrial compartmentalization. On the other hand, the Gly41[yields]Arg substitution, either in combination with the Pro11[yields]Leu polymorphism or by itself, is predicted to be responsible for the intraperoxisomal aggregation of the AGT protein. 50 refs., 8 figs., 4 tabs.

  12. Clinical and laboratory characteristics of patients with thyroid diseases with and without alanine aminotransferase levels above the upper tertile - Cross-sectional analytical study.

    PubMed

    Silva, Nathanael de Oliveira E; Ronsoni, Marcelo Fernando; Colombo, Bruno da Silveira; Corrêa, Carina Gabriela; Hatanaka, Simone Aiko; Canalli, Maria Heloisa Büsi da Silva; Schiavon, Leonardo de Lucca; Narciso-Schiavon, Janaína Luz

    2016-04-01

    Objective Thyroid disease affects 6.6% of the general population. The liver is fundamental in metabolizing thyroid hormones, and hepatocytes are often affected in thyroid disease. We aimed to compare clinical and laboratory parameters among thyroid disease patients with alanine aminotransferase (ALT) levels above vs. below the upper tertile. Subjects and methods A retrospective cross-sectional analytical study was conducted in the endocrinology clinic at Polydoro Ernani de São Thiago University Hospital. Patients with thyroid disease between August 2012 and January 2014 were included in the study. Clinical and laboratory parameters were collected from medical records. Results One hundred patients were included, of which 14.0% were male, with a mean age of 49.1 ± 14.4 years. ALT levels ranged from 9 to 90 U/L, and the ALT upper tertile was defined as 0,64 times the upper normal limit (xUNL). Patients with ALT levels above the upper tertile exhibited a higher proportion of systemic arterial hypertension (SAH), a higher mean abdominal circumference and a higher frequency of elevated TSH levels than did patients with ALT levels below the upper tertile. In multivariate analysis, ALT ≥ 0.64 (xUNL) was independently associated with abdominal circumference (odds ratio [OR] = 0.087, 95% confidence interval [CI] 0012-0167, P = 0.022). ALT (xUNL) correlated positively with total cholesterol (r = 0.213, P = 0.042). Conclusions In patients with thyroid diseases, it was observed that those with ALT above the upper tertile are associated with abdominal circumference and ALT levels correlate with total cholesterol. PMID:26331222

  13. Selectivity for d-Lactate Incorporation into the Peptidoglycan Precursors of Lactobacillus plantarum: Role of Aad, a VanX-Like d-Alanyl-d-Alanine Dipeptidase▿ †

    PubMed Central

    Deghorain, Marie; Goffin, Philippe; Fontaine, Laetitia; Mainardi, Jean-Luc; Daniel, Richard; Errington, Jeff; Hallet, Bernard; Hols, Pascal

    2007-01-01

    Lactobacillus plantarum produces peptidoglycan precursors ending in d-lactate instead of d-alanine, making the bacterium intrinsically resistant to vancomycin. The ligase Ddl of L. plantarum plays a central role in this specificity by synthesizing d-alanyl-d-lactate depsipeptides that are added to the precursor peptide chain by the enzyme MurF. Here we show that L. plantarum also encodes a d-Ala-d-Ala dipeptidase, Aad, which eliminates d-alanyl-d-alanine dipeptides that are produced by the Ddl ligase, thereby preventing their incorporation into the precursors. Although d-alanine-ended precursors can be incorporated into the cell wall, inactivation of Aad failed to suppress growth defects of L. plantarum mutants deficient in d-lactate-ended precursor synthesis. PMID:17400741

  14. Performance of an Optimized Paper-Based Test for Rapid Visual Measurement of Alanine Aminotransferase (ALT) in Fingerstick and Venipuncture Samples

    PubMed Central

    Noubary, Farzad; Coonahan, Erin; Schoeplein, Ryan; Baden, Rachel; Curry, Michael; Afdhal, Nezam; Kumar, Shailendra; Pollock, Nira R.

    2015-01-01

    Background A paper-based, multiplexed, microfluidic assay has been developed to visually measure alanine aminotransferase (ALT) in a fingerstick sample, generating rapid, semi-quantitative results. Prior studies indicated a need for improved accuracy; the device was subsequently optimized using an FDA-approved automated platform (Abaxis Piccolo Xpress) as a comparator. Here, we evaluated the performance of the optimized paper test for measurement of ALT in fingerstick blood and serum, as compared to Abaxis and Roche/Hitachi platforms. To evaluate feasibility of remote results interpretation, we also compared reading cell phone camera images of completed tests to reading the device in real time. Methods 96 ambulatory patients with varied baseline ALT concentration underwent fingerstick testing using the paper device; cell phone images of completed devices were taken and texted to a blinded off-site reader. Venipuncture serum was obtained from 93/96 participants for routine clinical testing (Roche/Hitachi); subsequently, 88/93 serum samples were captured and applied to paper and Abaxis platforms. Paper test and reference standard results were compared by Bland-Altman analysis. Findings For serum, there was excellent agreement between paper test and Abaxis results, with negligible bias (+4.5 U/L). Abaxis results were systematically 8.6% lower than Roche/Hitachi results. ALT values in fingerstick samples tested on paper were systematically lower than values in paired serum tested on paper (bias -23.6 U/L) or Abaxis (bias -18.4 U/L); a correction factor was developed for the paper device to match fingerstick blood to serum. Visual reads of cell phone images closely matched reads made in real time (bias +5.5 U/L). Conclusions The paper ALT test is highly accurate for serum testing, matching the reference method against which it was optimized better than the reference methods matched each other. A systematic difference exists between ALT values in fingerstick and paired

  15. Alanine-glyoxylate aminotransferase 2 (AGXT2) Polymorphisms Have Considerable Impact on Methylarginine and β-aminoisobutyrate Metabolism in Healthy Volunteers

    PubMed Central

    König, Jörg; Mieth, Maren; Sticht, Heinrich; Zolk, Oliver; Kralj, Ana; Heinrich, Markus R.; Fromm, Martin F.; Maas, Renke

    2014-01-01

    Elevated plasma concentrations of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine have repeatedly been linked to adverse clinical outcomes. Both methylarginines are substrates of alanine-glyoxylate aminotransferase 2 (AGXT2). It was the aim of the present study to simultaneously investigate the functional relevance and relative contributions of common AGXT2 single nucleotide polymorphisms (SNPs) to plasma and urinary concentrations of methylarginines as well as β-aminoisobutyrate (BAIB), a prototypic substrate of AGXT2. In a cohort of 400 healthy volunteers ADMA, SDMA and BAIB concentrations were determined in plasma and urine using HPLC-MS/MS and were related to the coding AGXT2 SNPs rs37369 (p.Val140Ile) and rs16899974 (p.Val498Leu). Volunteers heterozygous or homozygous for the AGXT2 SNP rs37369 had higher SDMA plasma concentrations by 5% and 20% (p = 0.002) as well as higher BAIB concentrations by 54% and 146%, respectively, in plasma and 237% and 1661%, respectively, in urine (both p<0.001). ADMA concentrations were not affected by both SNPs. A haplotype analysis revealed that the second investigated AGXT2 SNP rs16899974, which was not significantly linked to the other AGXT2 SNP, further aggravates the effect of rs37369 with respect to BAIB concentrations in plasma and urine. To investigate the impact of the amino acid exchange p.Val140Ile, we established human embryonic kidney cell lines stably overexpressing wild-type or mutant (p.Val140Ile) AGXT2 protein and assessed enzyme activity using BAIB and stable-isotope labeled [2H6]-SDMA as substrate. In vitro, the amino acid exchange of the mutant protein resulted in a significantly lower enzyme activity compared to wild-type AGXT2 (p<0.05). In silico modeling of the SNPs indicated reduced enzyme stability and substrate binding. In conclusion, SNPs of AGXT2 affect plasma as well as urinary BAIB and SDMA concentrations linking methylarginine metabolism to the common genetic trait of hyper

  16. Alanine-glyoxylate aminotransferase 2 (AGXT2) polymorphisms have considerable impact on methylarginine and β-aminoisobutyrate metabolism in healthy volunteers.

    PubMed

    Kittel, Anja; Müller, Fabian; König, Jörg; Mieth, Maren; Sticht, Heinrich; Zolk, Oliver; Kralj, Ana; Heinrich, Markus R; Fromm, Martin F; Maas, Renke

    2014-01-01

    Elevated plasma concentrations of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine have repeatedly been linked to adverse clinical outcomes. Both methylarginines are substrates of alanine-glyoxylate aminotransferase 2 (AGXT2). It was the aim of the present study to simultaneously investigate the functional relevance and relative contributions of common AGXT2 single nucleotide polymorphisms (SNPs) to plasma and urinary concentrations of methylarginines as well as β-aminoisobutyrate (BAIB), a prototypic substrate of AGXT2. In a cohort of 400 healthy volunteers ADMA, SDMA and BAIB concentrations were determined in plasma and urine using HPLC-MS/MS and were related to the coding AGXT2 SNPs rs37369 (p.Val140Ile) and rs16899974 (p.Val498Leu). Volunteers heterozygous or homozygous for the AGXT2 SNP rs37369 had higher SDMA plasma concentrations by 5% and 20% (p = 0.002) as well as higher BAIB concentrations by 54% and 146%, respectively, in plasma and 237% and 1661%, respectively, in urine (both p<0.001). ADMA concentrations were not affected by both SNPs. A haplotype analysis revealed that the second investigated AGXT2 SNP rs16899974, which was not significantly linked to the other AGXT2 SNP, further aggravates the effect of rs37369 with respect to BAIB concentrations in plasma and urine. To investigate the impact of the amino acid exchange p.Val140Ile, we established human embryonic kidney cell lines stably overexpressing wild-type or mutant (p.Val140Ile) AGXT2 protein and assessed enzyme activity using BAIB and stable-isotope labeled [²H₆]-SDMA as substrate. In vitro, the amino acid exchange of the mutant protein resulted in a significantly lower enzyme activity compared to wild-type AGXT2 (p<0.05). In silico modeling of the SNPs indicated reduced enzyme stability and substrate binding. In conclusion, SNPs of AGXT2 affect plasma as well as urinary BAIB and SDMA concentrations linking methylarginine metabolism to the common genetic trait of hyper

  17. Glycolysis and the Tricarboxylic Acid Cycle Are Linked by Alanine Aminotransferase during Hypoxia Induced by Waterlogging of Lotus japonicus1[W][OA

    PubMed Central

    Rocha, Marcio; Licausi, Francesco; Araújo, Wagner L.; Nunes-Nesi, Adriano; Sodek, Ladaslav; Fernie, Alisdair R.; van Dongen, Joost T.

    2010-01-01

    The role of nitrogen metabolism in the survival of prolonged periods of waterlogging was investigated in highly flood-tolerant, nodulated Lotus japonicus plants. Alanine production revealed to be a critical hypoxic pathway. Alanine is the only amino acid whose biosynthesis is not inhibited by nitrogen deficiency resulting from RNA interference silencing of nodular leghemoglobin. The metabolic changes that were induced following waterlogging can be best explained by the activation of alanine metabolism in combination with the modular operation of a split tricarboxylic acid pathway. The sum result of this metabolic scenario is the accumulation of alanine and succinate and the production of extra ATP under hypoxia. The importance of alanine metabolism is discussed with respect to its ability to regulate the level of pyruvate, and this and all other changes are discussed in the context of current models concerning the regulation of plant metabolism. PMID:20089769

  18. Effect of Four Weeks of β-alanine Supplementation on Muscle Carnosine and Blood Serum Lactate during Exercise in Male Rats.

    PubMed

    Naderi, Alireza; Hemat Far, Ahmad; Willems, Mark E T; Sadeghi, Mehdi

    2016-01-01

    β-alanine (BA) supplementation may increase muscle buffering capacity and affect physiological responses during exercise. We examined the effects of 4 weeks of BA supplementation on muscle carnosine and serum lactate in male rats. Rats (n = 24, age: 2 months, body weight: 265±22 g) were divided into a BA supplementation or control group. Along with aerobic acclimatization exercise (15 m·min(-1), 8-10 min·day(-1), 4 days·week(-1) for 4 weeks), the BA group had access to BA powder in their drinking water (1.8%) with the control group having access to plain water for 4 weeks. After 4 weeks, rats ran on a treadmill at speeds of 15, 20, 25, 30, and 35 m·min(-1), respectively, each for 4 min, in order to measure post-exercise serum lactate. Muscle carnosine and serum lactate levels were measured with high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbant assay (ELISA) procedures, respectively. Following BA supplementation, carnosine content in the m.rectus femoris increased by 117% (p < .01) and serum lactate decreased by 7.4% (p < .01). It was concluded that β-alanine supplementation increases muscle carnosine content and reduces serum lactate; these changes may indicate an adaptation of rat skeletal muscles to postpone peripheral muscle fatigue during high-intensity exercise. PMID:26745664

  19. Effect of L-tryptophan injection in rats on some enzymes of amino acid metabolism in liver. I. In vitro studies of the effect of L-tryptophan and its metabolites on the extramitochondrial L-alanine: 2-ketoglutaric aminotransferase.

    PubMed

    Katsos, A; Philippidis, H; Palaiologos, G

    1981-02-01

    Fed and fasted rats were injected with L-tryptophan (12.5 mg/100 g body weight) and the specific activities of L-glutamic: NAD oxidoreductase (deaminating) (EC 1.4.1.2) (GDH), L-aspartic-2-ketoglutaric aminotransferase (EC 2.6.1.1) (GOT) and L-alanine-2-ketoglutaric aminotransferase (EC 2.6.1.2) (GPT) from hepatic mitochondria and cytosol were compared. L-tryptophan results in a decrease of mitochondrial GDH activity by 22% and of cytosolic GPT and GOT by 42% and 38% respectively in the liver of fasted rats. Xanthurenate is a potent inhibitor of purified extramitochondrial GPT, whereas anthranilate and quinolinate are less potent inhibitors. L-tryptophan, 5-OH-tryptophan and indole exert a slight inhibition. Kynurenine, 5-OH-tryptamine, tryptamine, picolinic acid, nicotinic acid and indoloacetic acid do not show any inhibition of GPT. It is suggested that L-tryptophan injection inhibits extramitochondrial GPT by its transformation to xanthurenate and anthranilate. PMID:7227974

  20. Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis)

    PubMed Central

    Guha, Anirban; Gera, Sandeep; Sharma, Anshu

    2012-01-01

    Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu), iron (Fe), zinc (Zn), cobalt (Co) and manganese (Mn) and enzyme activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in riverine buffalo milk can be used as an indicator of subclinical mastitis (SCM) with the aim of developing suitable diagnostic kit for SCM. Trace elements and enzyme activity in milk were estimated with Atomic absorption Spectrophotometer, GBC 932 plus and biochemical methods, respectively. Somatic cell count (SCC) was done microscopically. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. A statistically significant (p<0.01) increase in SCC, Fe, Zn, Co and LDH occurred in SCM milk containing gram positive bacterial agents only. ALP was found to be elevated in milk infected by both gram positive and negative bacteria. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and SCC≥2×105 cells/ml of milk as the benchmark. Only ALP and Zn, the former being superior, were found to be suitable for diagnosis of SCM irrespective of etiological agents. LDH, Co and Fe can be introduced in the screening programs where Gram positive bacteria are omnipresent. It is recommended that both ALP and Zn be measured together in milk to diagnose buffalo SCM, irrespective of etiology. PMID:25049573

  1. Recurrent truncating mutations in alanine-glyoxylate aminotransferase gene in two South Indian families with primary hyperoxaluria type 1 causing later onset end-stage kidney disease

    PubMed Central

    Dutta, A. K.; Paulose, B. K.; Danda, S.; Alexander, S.; Tamilarasi, V.; Omprakash, S.

    2016-01-01

    Primary hyperoxaluria type 1 is an autosomal recessive inborn error of metabolism due to liver-specific peroxisomal enzyme alanine-glyoxylate transaminase deficiency. Here, we describe two unrelated patients who were diagnosed to have primary hyperoxaluria. Homozygous c.445_452delGTGCTGCT (p.L151Nfs*14) (Transcript ID: ENST00000307503; human genome assembly GRCh38.p2) (HGMD ID CD073567) mutation was detected in both the patients and the parents were found to be heterozygous carriers. Our patients developed end-stage renal disease at 23 years and 35 years of age. However, in the largest series published from OxalEurope cohort, the median age of end-stage renal disease for null mutations carriers was 9.9 years, which is much earlier than our cases. Our patients had slower progressions as compared to three unrelated patients from North India and Pakistan, who had homozygous c.302T>C (p.L101P) (HGMD ID CM093792) mutation in exon 2. Further, patients need to be studied to find out if c.445_452delGTGCTGCT mutation represents a founder mutation in Southern India. PMID:27512303

  2. Lingmao Formula Combined with Entecavir for HBeAg-Positive Chronic Hepatitis B Patients with Mildly Elevated Alanine Aminotransferase: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

    PubMed Central

    Zhu, Xiao-Jun; Sun, Xue-Hua; Zhou, Zheng-Hua; Liu, Shun-Qing; Lv, Hua; Li, Man; Li, Lu; Gao, Yue-Qiu

    2013-01-01

    Objective. To determine the efficacy and safety of Lingmao Formula combined with entecavir for HBeAg-positive chronic hepatitis B patients with mildly elevated alanine aminotransferase (ALT). Methods. 301 patients were randomly assigned to receive Lingmao Formula combined with entecavir (treatment group) or placebo combined with entecavir (control group) for 52 weeks. The outcomes of interest included the reduction of serum HBV DNA level, HBeAg loss, HBeAg seroconversion, ALT normalization, and histological improvement. Results. The mean decrease of serum HBV DNA level from baseline and the percentage of patients who had reduction in serum HBV DNA level ≥2 lg copies/mL in treatment group were significantly greater than that in control group (5.5 versus 5.4 lg copies/mL, P = 0.010; 98.5% versus 92.6%, P = 0.019). The percentage of HBeAg loss in treatment group was 22.8%, which was much higher than a percentage of 12.6% in control group (P = 0.038). There was no significant difference between the two groups in histological improvement. Safety was similar in the two groups. Conclusions. The combination of Lingmao Formula with entecavir could result in significant decrease of serum HBV DNA and increase of HBeAg loss for HBeAg-positive chronic hepatitis B patients with mildly elevated ALT without any serious adverse events. Clinical trial registration number is ChiCTR-TRC-09000594. PMID:24058372

  3. Incremental effects of 28 days of beta-alanine supplementation on high-intensity cycling performance and blood lactate in masters female cyclists.

    PubMed

    Glenn, J M; Gray, M; Stewart, R; Moyen, N E; Kavouras, S A; DiBrezzo, R; Turner, R; Baum, J

    2015-12-01

    Within the aging population, there exists a subset of individuals termed masters athletes (MA). As masters-level competition increases in popularity, MA must find methods to enhance individual athletic performance. Longitudinal beta-alanine (BA) supplementation is suggested to enhance physical capability during exercise; however, these effects have not been evaluated in MA. To examine the longitudinal effects of BA on time to exhaustion (TTE), total work completed (TWC), and lactate clearance in female MA cyclists. Twenty-two female MA (age = 53.3 ± 1.0) participated in this double-blind design. Subjects were randomly assigned to BA (n = 11; 800 mg BA + 8 g dextrose) or placebo (PLA; n = 11; 8 g dextrose) groups and supplemented 4 doses/day over 28 days. Every 7 days, subjects completed a cycling TTE at 120% VO2max, and TWC was calculated. Blood lactate was measured at baseline, immediate post, and 20-min post each TTE. No significant differences existed between groups for any variable at baseline (p > 0.05). After 28 days supplementation, BA had greater TTE (23 vs 1% change) and TWC (21 vs 2% change) than PLA (p < 0.05). Following the 20-min TTE recovery, lactate was 24% lower in BA compared to PLA (4.35 vs. 5.76 mmol/L, respectively). No differences existed for variables during intermittent weeks. 28 days of BA supplementation increased cycling performance via an enhanced time to exhaustion and total work completed with associated lactate clearance during passive rest in female MA. PMID:26255281

  4. The peroxisome proliferator-activated receptor α agonist, AZD4619, induces alanine aminotransferase-1 gene and protein expression in human, but not in rat hepatocytes: Correlation with serum ALT levels.

    PubMed

    Thulin, Petra; Bamberg, Krister; Buler, Marcin; Dahl, Björn; Glinghammar, Björn

    2016-09-01

    Alanine aminotransferase (ALT) in serum is the standard biomarker for liver injury. We have previously described a clinical trial with a novel selective peroxisome proliferator-activated receptor α (PPARα) agonist (AZD4619), which unexpectedly caused increased serum levels of ALT in treated individuals without any other evidence of liver injury. We pinpointed a plausible mechanism through which AZD4619 could increase serum ALT levels; namely through the PPARα-specific activation of the human ALT1 gene at the transcriptional level. In the present study, we present data from the preceding rat toxicity study, demonstrating that AZD4619 had no effect on rat serum ALT activity levels, and further experiments were performed to elucidate the mechanisms responsible for this species-related difference. Our results revealed that AZD4619 increased ALT1 protein expression in a dose-dependent manner in human, but not in rat primary hepatocytes. Cloning of the human and rat ALT1 promoters into luciferase vectors confirmed that AZD4619 induced only the human, but not the rat ALT1 gene promoter in a dose-dependent manner. In PPARα-GAL4 reporter gene assays, AZD4619 was >100-fold more potent on the human vs. rat PPARα levels, explaining the differences in induction of the ALT1 gene between the species at the concentration range tested. These data demonstrate the usefulness of the human and rat ALT1 reporter gene assays for testing future drug candidates at the preclinical stage. In drug discovery projects, these assays elucidate whether elevations in ALT levels observed in vivo or in the clinic are due to metabolic effects rather than a toxic event in the liver. PMID:27430334

  5. Evolution of alanine:glyoxylate aminotransferase 1 peroxisomal and mitochondrial targeting. A survey of its subcellular distribution in the livers of various representatives of the classes Mammalia, Aves and Amphibia.

    PubMed

    Danpure, C J; Fryer, P; Jennings, P R; Allsop, J; Griffiths, S; Cunningham, A

    1994-08-01

    As part of a wider study on the molecular evolution of alanine:glyoxylate aminotransferase 1 (AGT1) intracellular compartmentalization, we have determined the subcellular distribution of immunoreactive AGT1, using postembedding protein A-gold immunoelectron microscopy, in the livers of various members of the classes Mammalia, Aves, and Amphibia. As far as organellar distribution is concerned, three categories could be distinguished. In members of the first category (type I), all, or nearly all, of the immunoreactive AGT1 was concentrated within the peroxisomes. In the second category (type II), AGT1 was found more evenly distributed in both peroxisomes and mitochondria. In the third category (type III), AGT1 was localized mainly within the mitochondria with much lower, but widely variable, amounts in the peroxisomes. Type I animals include the human, two great apes (gorilla, orangutan), two Old World monkeys (anubis baboon, Japanese macaque), a New World monkey (white-faced Saki monkey), a lago, morph (European rabbit), a bat (Seba's short-tailed fruit bat), two caviomorph rodents (guinea pig, orange-rumped agouti), and two Australian marsupials (koala, Bennett's wallaby). Type II animals include two New World monkeys (common marmoset, cotton-top tamarin), three prosimians (brown lemur, fat-tailed dwarf lemur, pygmy slow loris), five rodents (a hybrid crested porcupine, Colombian ground squirrel, laboratory rat, laboratory mouse, golden hamster), an American marsupial (grey short-tailed opossum), and a bird (raven). Type III animals include the large tree shrew, three insectivores (common Eurasian mole, European hedgehog, house shrew), four carnivores (domestic cat, ocelot, domestic dog, polecat ferret), and an amphibian (common frog). In addition to these categories, some animals (e.g. guinea pig, common frog) possessed significant amounts of cytosolic AGT1. Whereas the subcellular distribution of AGT1 in some orders (e.g. Insectivora and Carnivora) did not appear

  6. Lactation

    PubMed Central

    1989-01-01

    Lactation is the most energy-efficient way to provide for the dietary needs of young mammals, their mother's milk being actively protective, immunomodulatory, and ideal for their needs. Intrauterine mammary gland development in the human female is already apparent by the end of the sixth week of gestation. During puberty and adolescence secretions of the anterior pituitary stimulate the maturation of the graafian follicles in the ovaries and stimulate the secretion of follicular estrogens, which stimulate development of the mammary ducts. Pregnancy has the most dramatic effect on the breast, but development of the glandular breast tissue and deposition of fat and connective tissue continue under the influence of cyclic sex-hormone stimulation. Many changes occur in the nipple and breast during pregnancy and at delivery as a prelude to lactation. Preparation of the breasts is so effective that lactation could commence even if pregnancy were discontinued at 16 weeks. Following birth, placental inhibition of milk synthesis is removed, and a woman's progesterone blood levels decline rapidly. The breasts fill with milk, which is a high-density, low-volume feed called colostrum until about 30 hours after birth. Because it is not the level of maternal hormones, but the efficiency of infant suckling and/or milk removal that governs the volume of milk produced in each breast, mothers who permit their infants to feed ad libitum commonly observe that they have large volumes of milk 24-48 hours after birth. The two maternal reflexes involved in lactation are the milk-production and milk-ejection reflex. A number of complementary reflexes are involved when the infant feeds: the rooting reflex (which programmes the infant to search for the nipple), the sucking reflex (rhythmic jaw action creating negative pressure and a peristaltic action of the tongue), and the swallowing reflex. The infant's instinctive actions need to be consolidated into learned behaviour in the postpartum

  7. Combined use of l-alanine tert butyl ester lactate and trimethyl-β-cyclodextrin for the enantiomeric separations of 2-arylpropionic acids nonsteroidal anti-inflammatory drugs.

    PubMed

    Mavroudi, Maria C; Kapnissi-Christodoulou, Constantina P

    2015-10-01

    In this study, a new CE method, employing a binary system of trimethyl-β-CD (TM-β-CD) and a chiral amino acid ester-based ionic liquid (AAIL), was developed for the chiral separation of seven 2-arylpropionic acid nonsteroidal anti-inflammatory drugs (NSAIDs). In particular, the enantioseparation of ibuprofen, ketoprofen, carprofen, indoprofen, flurbiprofen, naproxen, and fenoprofen was improved significantly by supporting the BGE with the chiral AAIL l-alanine tert butyl ester lactate (l-AlaC4 Lac). Parameters, such as concentrations of TM-β-CD and l-AlaC4 Lac, and buffer pH, were systematically examined in order to optimize the chiral separation of each NSAID. It was observed that the addition of the AAIL into the BGE improved both resolution and efficiency significantly. After optimization of separation conditions, baseline separation (Rs >1.5) of five of the analytes was achieved in less than 11 min, while the resolution of ibuprofen and flurbiprofen was approximately 1.2. The optimized enantioseparation conditions for all analytes involve a BGE of 5 mM sodium acetate/acetic acid (pH 5.0), an applied voltage of 30 kV, and a temperature of 20°C. In addition, the results obtained by computing the %-RSD values of the EOF and the two enantiomer peaks, demonstrated excellent run-to-run, batch-to-batch, and day-to-day reproducibilities. PMID:26080944

  8. AGXT2: a promiscuous aminotransferase

    PubMed Central

    Rodionov, Roman N.; Jarzebska, Natalia; Weiss, Norbert; Lentz, Steven R.

    2014-01-01

    Alanine-glyoxylate aminotransferase 2 (AGXT2) is a multifunctional mitochondrial aminotransferase that was first identified in 1978. The physiological importance of AGXT2 was largely overlooked for three decades because AGXT2 is less active in glyoxylate metabolism than AGXT1, the enzyme that is deficient in primary hyperoxaluria type I. Recently, several novel functions of AGXT2 have been “rediscovered” in the setting of modern genomic and metabolomic studies. It is now apparent that AGXT2 has multiple substrates and products and that altered AGXT2 activity may contribute to the pathogenesis of cardiovascular, renal, neurological and hematological diseases. This article reviews the biochemical properties and physiological functions of AGXT2, its unique role at the intersection of key mitochondrial pathways, and its potential as a drug target. PMID:25294000

  9. Antiretroviral Drugs and Risk of Chronic Alanine Aminotransferase Elevation in Human Immunodeficiency Virus (HIV)-Monoinfected Persons: The Data Collection on Adverse Events of Anti-HIV Drugs Study.

    PubMed

    Kovari, Helen; Sabin, Caroline A; Ledergerber, Bruno; Ryom, Lene; Reiss, Peter; Law, Matthew; Pradier, Christian; Dabis, Francois; d'Arminio Monforte, Antonella; Smith, Colette; de Wit, Stephane; Kirk, Ole; Lundgren, Jens D; Weber, Rainer

    2016-01-01

    Background.  Although human immunodeficiency virus (HIV)-positive persons on antiretroviral therapy (ART) frequently have chronic liver enzyme elevation (cLEE), the underlying cause is often unclear. Methods.  Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) Study participants without chronic viral hepatitis were observed to the earliest of cLEE (elevated aminotransferase ≥6 months), death, last follow-up, or January 2, 2014. Antiretroviral treatment exposure was categorized as follows: no exposure and ongoing short- and long-term exposure (<2 or ≥2 years) after initiation. Association between development of cLEE and ART exposure was investigated using Poisson regression. Results.  Among 21 485 participants observed for 105 413 person-years (PY), 6368 developed cLEE (incidence 6.04/100 PY; 95% confidence interval [CI], 5.89-6.19). Chronic liver enzyme elevation was associated with short-and long-term exposure to didanosine (<2 years rate ratio [RR] = 1.29, 95% CI, 1.11-1.49; >2 years RR = 1.26, 95% CI, 1.13-1.41); stavudine (<2 years RR = 1.51, 95% CI, 1.26-1.81; >2 years RR = 1.17, 95% CI, 1.03-1.32), and tenofovir disoproxil fumarate (<2 years RR = 1.55, 95% CI, 1.40-1.72; >2 years RR = 1.18, 95% CI, 1.05-1.32), but only short-term exposure to nevirapine (<2 years RR = 1.44, 95% CI, 1.29-1.61), efavirenz (<2 years RR = 1.14, 95% CI, 1.03-1.26), emtricitabine (<2 years RR = 1.18, 95% CI, 1.04-1.33), and atazanavir (<2 years RR = 1.20, 95% CI, 1.04-1.38). Chronic liver enzyme elevation was not associated with use of lamivudine, abacavir, and other protease inhibitors. Mortality did not differ between participants with and without cLEE. Conclusions.  Although didanosine, stavudine, nevirapine, and efavirenz have been described to be hepatotoxic, we additionally observed a consistent association between tenofovir and cLEE emerging within the first 2 years after drug initiation. This novel tenofovir-cLEE signal should be further investigated

  10. Antiretroviral Drugs and Risk of Chronic Alanine Aminotransferase Elevation in Human Immunodeficiency Virus (HIV)-Monoinfected Persons: The Data Collection on Adverse Events of Anti-HIV Drugs Study

    PubMed Central

    Kovari, Helen; Sabin, Caroline A.; Ledergerber, Bruno; Ryom, Lene; Reiss, Peter; Law, Matthew; Pradier, Christian; Dabis, Francois; d'Arminio Monforte, Antonella; Smith, Colette; de Wit, Stephane; Kirk, Ole; Lundgren, Jens D.; Weber, Rainer

    2016-01-01

    Background. Although human immunodeficiency virus (HIV)-positive persons on antiretroviral therapy (ART) frequently have chronic liver enzyme elevation (cLEE), the underlying cause is often unclear. Methods. Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) Study participants without chronic viral hepatitis were observed to the earliest of cLEE (elevated aminotransferase ≥6 months), death, last follow-up, or January 2, 2014. Antiretroviral treatment exposure was categorized as follows: no exposure and ongoing short- and long-term exposure (<2 or ≥2 years) after initiation. Association between development of cLEE and ART exposure was investigated using Poisson regression. Results. Among 21 485 participants observed for 105 413 person-years (PY), 6368 developed cLEE (incidence 6.04/100 PY; 95% confidence interval [CI], 5.89–6.19). Chronic liver enzyme elevation was associated with short-and long-term exposure to didanosine (<2 years rate ratio [RR] = 1.29, 95% CI, 1.11–1.49; >2 years RR = 1.26, 95% CI, 1.13–1.41); stavudine (<2 years RR = 1.51, 95% CI, 1.26–1.81; >2 years RR = 1.17, 95% CI, 1.03–1.32), and tenofovir disoproxil fumarate (<2 years RR = 1.55, 95% CI, 1.40–1.72; >2 years RR = 1.18, 95% CI, 1.05–1.32), but only short-term exposure to nevirapine (<2 years RR = 1.44, 95% CI, 1.29–1.61), efavirenz (<2 years RR = 1.14, 95% CI, 1.03–1.26), emtricitabine (<2 years RR = 1.18, 95% CI, 1.04–1.33), and atazanavir (<2 years RR = 1.20, 95% CI, 1.04–1.38). Chronic liver enzyme elevation was not associated with use of lamivudine, abacavir, and other protease inhibitors. Mortality did not differ between participants with and without cLEE. Conclusions. Although didanosine, stavudine, nevirapine, and efavirenz have been described to be hepatotoxic, we additionally observed a consistent association between tenofovir and cLEE emerging within the first 2 years after drug initiation. This novel tenofovir-cLEE signal should be

  11. Comparative aspects of aminotransferases in the rat, pigeon and rainbow trout.

    PubMed

    Cornish, E C; Cussen, C M; Hird, F J; Todd, P E

    1978-01-01

    1. The activities of aminotransferases catalysing the transfer of amino groups from aspartate, alanine and leucine to 2-oxoglutarate in different tissues of the rat, pigeon and trout have been determined. 2. Alanine-2-oxoglutarate aminotransferase was high in the liver of the rat and trout and low in that of the pigeon. 3. Aspartate-2-oxoglutarate aminotransferase was usually the dominant aminotransferase in all tissues and was highest in oxidative tissues where the TCA cycle is active. Its activity in the various livers is not correlated with the function of aspartate in nitrogen excretion. 4. The activity of aspartate-2-oxoglutarate aminotransferase in oxidative tissues argues that aspartate in conjunction with this enzyme serves as a buffer of oxaloacetate to keep the TCA cycle running and/or to mediate the transfer of reducing equivalents across mitochondrial membranes. PMID:318383

  12. Ornithine δ-aminotransferase

    PubMed Central

    Stránská, Jana; Kopečný, David; Tylichová, Martina; Snégaroff, Jacques

    2008-01-01

    This review deals with biochemical and physiological aspects of plant ornithine d-aminotransferase (OAT, EC 2.6.1.13). OAT is a mitochondrial enzyme containing pyridoxal-5′-phosphate as a cofactor, which catalyzes the conversion of L-ornithine to L-glutamate γ-semialdehyde using 2-oxoglutarate as a terminal amino group acceptor. It has been described in humans, animals, insects, plants and microorganisms. Based on the crystal structure of human OAT, both substrate binding and reaction mechanism of the enzyme are well understood. OAT shows a large structural and mechanistic similarity to other enzymes from the subgroup III of aminotransferases, which transfer an amino group from a carbon atom that does not carry a carboxyl function. In plants, the enzyme has been implicated in proline biosynthesis and accumulation (via pyrroline-5-carboxylate), which represents a way to regulate cellular osmolarity in response to osmotic stress. However, the exact metabolic pathway involving OAT remains a subject of controversy. PMID:19513195

  13. Respiration of [14C]alanine by the ectomycorrhizal fungus Paxillus involutus.

    PubMed

    Chalot, M; Brun, A; Finlay, R D; Söderström, B

    1994-08-01

    The ectomycorrhizal fungus Paxillus involutus efficiently took up exogenously supplied [14C]alanine and rapidly converted it to pyruvate, citrate, succinate, fumarate and to CO2, thus providing direct evidence for the utilisation of alanine as a respiratory substrate. [14C]alanine was further actively metabolised to glutamate, glutamine and aspartate. Exposure to aminooxyacetate completely suppressed 14CO2 evolution and greatly reduced the flow of carbon from [14C]alanine to tricarboxylic acid cycle intermediates and amino acids, suggesting that alanine aminotransferase plays a pivotal role in alanine metabolism in Paxillus involutus. PMID:8082830

  14. Structure and function of branched chain aminotransferases.

    PubMed

    Hutson, S

    2001-01-01

    Branched chain aminotransferases (BCATs) catalyze transamination of the branched chain amino acids (BCAAs) leucine, isoleucine, and valine. Except for the Escherichia coli and Salmonella proteins, which are homohexamers arranged as a double trimer, the BCATs are homodimers. Structurally, the BCATs belong to the fold type IV class of pyridoxal phosphate (PLP) enzymes. Other members are D-alanine aminotransferase and 4-amino-4-deoxychorismate lyase. Catalysis is on the re face of the PLP cofactor, whereas in other classes, catalysis occurs from the si face of PLP. Crystal structures of the fold type IV proteins show that they are distinct from the fold type I aspartate aminotransferase family and represent a new protein fold. Because the fold type IV enzymes catalyze diverse reactions, it is not surprising that the greatest structural similarities involve residues that participate in PLP binding rather than residues involved in substrate binding. The BCATs are widely distributed in the bacterial kingdom, where they are involved in the synthesis/degradation of the BCAAs. Bacteria contain a single BCAT. In eukaryotes there are two isozymes, one is mitochondrial (BCATm) and the other is cytosolic (BCATc). In mammals, BCATm is in most tissues, and BCATm is thought to be important in body nitrogen metabolism. BCATc is largely restricted to the central nervous system (CNS). Recently, BCATc has been recognized as a target of the neuroactive drug gabapentin. BCATc is involved in excitatory neurotransmitter glutamate synthesis in the CNS. Ongoing structural studies of the BCATs may facilitate the design of therapeutic compounds to treat neurodegenerative disorders involving disturbances of the glutamatergic system. PMID:11642362

  15. Molecular cloning, expression and characterization of pyridoxamine–pyruvate aminotransferase

    PubMed Central

    Yoshikane, Yu; Yokochi, Nana; Ohnishi, Kouhei; Hayashi, Hideyuki; Yagi, Toshiharu

    2006-01-01

    Pyridoxamine–pyruvate aminotransferase is a PLP (pyridoxal 5′-phosphate) (a coenzyme form of vitamin B6)-independent aminotransferase which catalyses a reversible transamination reaction between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The gene encoding the enzyme has been identified, cloned and overexpressed for the first time. The mlr6806 gene on the chromosome of a symbiotic nitrogen-fixing bacterium, Mesorhizobium loti, encoded the enzyme, which consists of 393 amino acid residues. The primary sequence was identical with those of archaeal aspartate aminotransferase and rat serine–pyruvate aminotransferase, which are PLP-dependent aminotransferases. The results of fold-type analysis and the consensus amino acid residues found around the active-site lysine residue identified in the present study showed that the enzyme could be classified into class V aminotransferases of fold type I or the AT IV subfamily of the α family of the PLP-dependent enzymes. Analyses of the absorption and CD spectra of the wild-type and point-mutated enzymes showed that Lys197 was essential for the enzyme activity, and was the active-site lysine residue that corresponded to that found in the PLP-dependent aminotransferases, as had been suggested previously [Hodsdon, Kolb, Snell and Cole (1978) Biochem. J. 169, 429–432]. The Kd value for pyridoxal determined by means of CD was 100-fold lower than the Km value for it, suggesting that Schiff base formation between pyridoxal and the active-site lysine residue is partially rate determining in the catalysis of pyridoxal. The active-site structure and evolutionary aspects of the enzyme are discussed. PMID:16545075

  16. Evaluation of aminotransferase abnormality in dengue patients: A meta analysis.

    PubMed

    Wang, Xiao-Jun; Wei, Hai-Xia; Jiang, Shi-Chen; He, Cheng; Xu, Xiu-Juan; Peng, Hong-Juan

    2016-04-01

    Dengue virus is a type of flavivirus transmitted by Aedes mosquitoes. The symptoms of infection by this virus range from asymptomatic or mild symptomatic dengue fever (DF) to dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). Significant abnormality in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) has been shown in a large number of dengue infection cases and to be indicator for liver injury provided that there are no other combined infections or liver injury. This study aims to assess the abnormal levels of liver aminotransferase in dengue patients. The related literature was searched in multiple databases, including PubMed, Embase, Google Scholar and Cochrane Library. The literature was selected through strict inclusion and exclusion criteria, and the quantitative synthesis of the liver aminotransferase abnormality was performed with R software. The fixed or random effects model was employed based on the results of the statistical test for homogeneity. In total, 15 studies were included. The proportion of AST abnormality with 95% confidence interval (95% CI) was 0.80 (95% CI: 0.56-0.92) in DHF patients and 0.75 (95% CI: 0.63-0.84) in DF patients; the proportion of ALT abnormality was 0.54 (95% CI: 0.34-0.73) in DHF patients and 0.52 (95% CI: 0.41-0.63) in DF patients. Serum ALT and AST levels may be indicators for evaluating liver injury in dengue infection and for diagnosis and treatment effect. PMID:26739659

  17. Lactating Porcine Mammary Tissue Catabolizes Branched-Chain Amino Acids for Glutamine and Aspartate Synthesis1–3

    PubMed Central

    Li, Peng; Knabe, Darrell A.; Kim, Sung Woo; Lynch, Christopher J.; Hutson, Susan M.; Wu, Guoyao

    2009-01-01

    The uptake of branched-chain amino acids (BCAA) from plasma by lactating porcine mammary gland substantially exceeds their output in milk, whereas glutamine output is 125% greater than its uptake from plasma. In this study, we tested the hypothesis that BCAA are catabolized for glutamine synthesis in mammary tissue. Mammary tissue slices from sows on d 28 of lactation were incubated at 37°C for 1 h in Krebs buffer containing 0.5 or 2 mmol/L l-[1-14C]– or l-[U-14C]–labeled leucine, isoleucine, or valine. Rates of BCAA transport and degradation in mammary tissue were high, with ∼60% of transaminated BCAA undergoing oxidative decarboxylation and the remainder being released as branched-chain α-ketoacids (BCKA). Most (∼70%) of the decarboxylated BCAA were oxidized to CO2. Rates of net BCAA transamination were similar to rates of glutamate, glutamine, aspartate, asparagine, and alanine synthesis. Consistent with the metabolic data, mammary tissue expressed BCAA aminotransferase (BCAT), BCKA decarboxylase, glutamine synthetase (GS), glutamate-oxaloacetate aminotransferase, glutamate-pyruvate aminotransferase, and asparagine synthetase, but no phosphate-activated glutaminase, activity. Western blot analysis indicated relatively high levels of mitochondrial and cytosolic isoforms of BCAT, as well as BCKA dehydrogenase and GS proteins in mammary tissue. Our results demonstrate that glutamine and aspartate (abundant amino acids in milk protein) were the major nitrogenous products of BCAA catabolism in lactating porcine mammary tissue and provide a biochemical basis to explain an enrichment of glutamine and aspartate in sow milk. PMID:19549750

  18. The Effect of Artichoke Leaf Extract on Alanine Aminotransferase and Aspartate Aminotransferase in the Patients with Nonalcoholic Steatohepatitis.

    PubMed

    Rangboo, Vajiheh; Noroozi, Mostafa; Zavoshy, Roza; Rezadoost, Seyed Amirmansoor; Mohammadpoorasl, Asghar

    2016-01-01

    Background. Based on recent basic and clinical investigations, the extract of artichoke (Cynara scolymus) leaf has been revealed to be used for hepatoprotective and cholesterol reducing purposes. We aimed to assess the therapeutic effects of artichoke on biochemical and liver biomarkers in patients with nonalcoholic steatohepatitis (NASH). Methods. In a randomized double blind clinical trial, 60 consecutive patients suffering NASH were randomly assigned to receive Cynara scolymus extract (as 6 tablets per day consisting of 2700 mg extract of the herb) as the intervention group or placebo as the control group for two months. Results. Comparing changes in study markers following interventions showed improvement in liver enzymes. The levels of triglycerides and cholesterol were significantly reduced in the group treated with Cynara scolymus when compared to placebo group. To compare the role of Cynara scolymus use with placebo in changes in study parameters, multivariate linear regression models were employed indicating higher improvement in liver enzymes and also lipid profile particularly triglycerides and total cholesterol following administration of Cynara scolymus in comparison with placebo use. Conclusion. This study sheds light on the potential hepatoprotective activity and hypolipidemic effect of Cynara scolymus in management of NASH. This clinical trial is registered in the IRCT, Iranian Registry of Clinical Trials, by number IRCT2014070218321N1. PMID:27293900

  19. The Effect of Artichoke Leaf Extract on Alanine Aminotransferase and Aspartate Aminotransferase in the Patients with Nonalcoholic Steatohepatitis

    PubMed Central

    Rangboo, Vajiheh; Noroozi, Mostafa; Zavoshy, Roza; Rezadoost, Seyed Amirmansoor; Mohammadpoorasl, Asghar

    2016-01-01

    Background. Based on recent basic and clinical investigations, the extract of artichoke (Cynara scolymus) leaf has been revealed to be used for hepatoprotective and cholesterol reducing purposes. We aimed to assess the therapeutic effects of artichoke on biochemical and liver biomarkers in patients with nonalcoholic steatohepatitis (NASH). Methods. In a randomized double blind clinical trial, 60 consecutive patients suffering NASH were randomly assigned to receive Cynara scolymus extract (as 6 tablets per day consisting of 2700 mg extract of the herb) as the intervention group or placebo as the control group for two months. Results. Comparing changes in study markers following interventions showed improvement in liver enzymes. The levels of triglycerides and cholesterol were significantly reduced in the group treated with Cynara scolymus when compared to placebo group. To compare the role of Cynara scolymus use with placebo in changes in study parameters, multivariate linear regression models were employed indicating higher improvement in liver enzymes and also lipid profile particularly triglycerides and total cholesterol following administration of Cynara scolymus in comparison with placebo use. Conclusion. This study sheds light on the potential hepatoprotective activity and hypolipidemic effect of Cynara scolymus in management of NASH. This clinical trial is registered in the IRCT, Iranian Registry of Clinical Trials, by number IRCT2014070218321N1. PMID:27293900

  20. Isolation and partial characterization of a broad specificity aminotransferase from Leishmania mexicana promastigotes.

    PubMed

    Vernal, J; Cazzulo, J J; Nowicki, C

    1998-10-30

    A broad specificity aminotransferase (BSAT), with high activity with both, aromatic amino acids and aspartate as substrates, was purified to homogeneity from promastigotes of Leishmania mexicana by a method involving chromatography on DEAE-cellulose, Red-120-Sepharose and Mono Q, and gel filtration on Sephacryl S-200. The purified enzyme showed a single band in SDS-polyacrylamide gel electrophoresis, with an apparent molecular mass of 45 kDa. Since the apparent molecular mass of the native enzyme, determined by gel filtration, was 90 kDa, the native enzyme is a dimer of similar subunits. The amino acid composition was determined, as well as the sequence of four internal peptides obtained by tryptic digestion. Two of these peptides, consisting of 49 amino acid residues in total, showed high similarity (57%) with corresponding sequences of plant aspartate aminotransferases, whereas they had only 33% identity with the aromatic aminotransferase of Escherichia coli, and 16% identity with the tyrosine aminotransferase from the related parasite Trypanosoma cruzi. The BSAT contained only one 1/2 Cys residue per monomer. The optimal pH for the enzyme reaction, with tyrosine and alpha-oxoglutarate as substrates, was 7.0. The apparent Km values for tyrosine, phenylalanine, tryptophan and glutamate, with oxaloacetate as co-substrate, were 1.3, 0.9, 0.9 and 171.8 mM, respectively; the value for aspartate with alpha-oxoglutarate as co-substrate was 2.5 mM, and that for alanine with alpha-oxoglutarate as co-substrate was 216 mM. The values for pyruvate, alpha-oxoglutarate and oxaloacetate, with tyrosine as co-substrate, were 5.6, 0.71 and 0.12 mM, respectively. These results suggest that the enzyme is a broad-specificity aminotransferase, able to transaminate the aromatic amino acids, aspartate, and to a lower extent alanine, with high sequence similarity to aspartate aminotransferases. PMID:9851609

  1. Active-site Arg --> Lys substitutions alter reaction and substrate specificity of aspartate aminotransferase.

    PubMed

    Vacca, R A; Giannattasio, S; Graber, R; Sandmeier, E; Marra, E; Christen, P

    1997-08-29

    Arg386 and Arg292 of aspartate aminotransferase bind the alpha and the distal carboxylate group, respectively, of dicarboxylic substrates. Their substitution with lysine residues markedly decreased aminotransferase activity. The kcat values with L-aspartate and 2-oxoglutarate as substrates under steady-state conditions at 25 degrees C were 0.5, 2.0, and 0.03 s-1 for the R292K, R386K, and R292K/R386K mutations, respectively, kcat of the wild-type enzyme being 220 s-1. Longer dicarboxylic substrates did not compensate for the shorter side chain of the lysine residues. Consistent with the different roles of Arg292 and Arg386 in substrate binding, the effects of their substitution on the activity toward long chain monocarboxylic (norleucine/2-oxocaproic acid) and aromatic substrates diverged. Whereas the R292K mutation did not impair the aminotransferase activity toward these substrates, the effect of the R386K substitution was similar to that on the activity toward dicarboxylic substrates. All three mutant enzymes catalyzed as side reactions the beta-decarboxylation of L-aspartate and the racemization of amino acids at faster rates than the wild-type enzyme. The changes in reaction specificity were most pronounced in aspartate aminotransferase R292K, which decarboxylated L-aspartate to L-alanine 15 times faster (kcat = 0.002 s-1) than the wild-type enzyme. The rates of racemization of L-aspartate, L-glutamate, and L-alanine were 3, 5, and 2 times, respectively, faster than with the wild-type enzyme. Thus, Arg --> Lys substitutions in the active site of aspartate aminotransferase decrease aminotransferase activity but increase other pyridoxal 5'-phosphate-dependent catalytic activities. Apparently, the reaction specificity of pyridoxal 5'-phosphate-dependent enzymes is not only achieved by accelerating the specific reaction but also by preventing potential side reactions of the coenzyme substrate adduct. PMID:9268327

  2. Short communication: reference values for blood parameters in Holstein dairy cows: effects of parity, stage of lactation, and season of production.

    PubMed

    Cozzi, G; Ravarotto, L; Gottardo, F; Stefani, A L; Contiero, B; Moro, L; Brscic, M; Dalvit, P

    2011-08-01

    Confidence intervals for blood parameters used for nutritional and metabolic profile testing in cattle were calculated for clinically normal lactating Holstein cows, taking into account the effects of parity, stage of lactation, and season. Blood samples were collected from 740 cows in 33 Italian dairy herds according to a predefined protocol. Herds were visited during summer and the following winter, sampling 12 lactating cows at each visit (4 primiparous and 8 multiparous). Six cows were selected from the early-lactation group (days in milk: 10 to 89) and the other 6 were selected from the mid-lactation group (days in milk: 90 to 215). Cow selection criteria excluded animals clinically exposed to periparturient diseases as well as animals not considered in good health by a veterinary clinical examination. For each blood variable, outliers were identified and discarded. Data were then analyzed for their Gaussian distribution and variables with not normal distribution were log-transformed to adjust for lack of normality. Herd mean values were calculated for each blood parameter according to 3 main classification factors: parity (primiparous vs. multiparous), stage of lactation (early vs. mid) and season of production (summer vs. winter). The resulting data set was statistically analyzed using a mixed model with the fixed effects of these factors, their interactions, and the random effect of herd. General 95% confidence intervals were calculated for blood variables that showed a relevant herd variance component such as albumin, triglycerides, aspartate, urea, glucose, alanine aminotransferase, lactate dehydrogenase, direct and total bilirubin, calcium, magnesium, and potassium. For the remaining parameters, specific confidence intervals were calculated for each level of the significant main factors. Parity affected blood concentration of total protein, globulin, creatinine, alkaline phosphatase, gamma glutamyl transferase, creatinine kinase, and phosphorus. Blood

  3. Structural studies of Pseudomonas and Chromobacterium ω-aminotransferases provide insights into their differing substrate specificity

    SciTech Connect

    Sayer, Christopher; Isupov, Michail N.; Westlake, Aaron; Littlechild, Jennifer A.

    2013-04-01

    The X-ray structures of two ω-aminotransferases from P. aeruginosa and C. violaceum in complex with an inhibitor offer the first detailed insight into the structural basis of the substrate specificity of these industrially important enzymes. The crystal structures and inhibitor complexes of two industrially important ω-aminotransferase enzymes from Pseudomonas aeruginosa and Chromobacterium violaceum have been determined in order to understand the differences in their substrate specificity. The two enzymes share 30% sequence identity and use the same amino acceptor, pyruvate; however, the Pseudomonas enzyme shows activity towards the amino donor β-alanine, whilst the Chromobacterium enzyme does not. Both enzymes show activity towards S-α-methylbenzylamine (MBA), with the Chromobacterium enzyme having a broader substrate range. The crystal structure of the P. aeruginosa enzyme has been solved in the holo form and with the inhibitor gabaculine bound. The C. violaceum enzyme has been solved in the apo and holo forms and with gabaculine bound. The structures of the holo forms of both enzymes are quite similar. There is little conformational difference observed between the inhibitor complex and the holoenzyme for the P. aeruginosa aminotransferase. In comparison, the crystal structure of the C. violaceum gabaculine complex shows significant structural rearrangements from the structures of both the apo and holo forms of the enzyme. It appears that the different rigidity of the protein scaffold contributes to the substrate specificity observed for the two ω-aminotransferases.

  4. Use of protease sensitivity to probe the conformations of newly synthesised mutant forms of mitochondrial aspartate aminotransferase.

    PubMed

    Azzariti, A; Giannattasio, S; Doonan, S; Merafina, R S; Marra, E; Quagliariello, E

    1995-10-24

    Sensitivity to digestion with pronase has been used to show that the precursor form of mitochondrial aspartate aminotransferase, the form lacking the N-terminal presequence, that with a deletion of the first 9 residues and mutants of the mature enzyme in which residue Cys-166 is mutated to alanine or serine, all retain unfolded conformations after synthesis in a reticulocyte lysate. In the presence of lysed mitochondria the various forms of mitochondrial aspartate aminotransferase retained their susceptibilities to pronase in a way that mirrored the efficiencies with which they are imported into intact mitochondria. The results are interpreted as showing that the presequence of mitochondrial aspartate aminotransferase is not uniquely required for interaction with cytosolic factors required to maintain the newly synthesised protein in a form competent for interacting with, and being imported into, mitochondria. PMID:7488044

  5. Three Different Classes of Aminotransferases Evolved Prephenate Aminotransferase Functionality in Arogenate-competent Microorganisms*

    PubMed Central

    Graindorge, Matthieu; Giustini, Cécile; Kraut, Alexandra; Moyet, Lucas; Curien, Gilles; Matringe, Michel

    2014-01-01

    The aromatic amino acids phenylalanine and tyrosine represent essential sources of high value natural aromatic compounds for human health and industry. Depending on the organism, alternative routes exist for their synthesis. Phenylalanine and tyrosine are synthesized either via phenylpyruvate/4-hydroxyphenylpyruvate or via arogenate. In arogenate-competent microorganisms, an aminotransferase is required for the transamination of prephenate into arogenate, but the identity of the genes is still unknown. We present here the first identification of prephenate aminotransferases (PATs) in seven arogenate-competent microorganisms and the discovery that PAT activity is provided by three different classes of aminotransferase, which belong to two different fold types of pyridoxal phosphate enzymes: an aspartate aminotransferase subgroup 1β in tested α- and β-proteobacteria, a branched-chain aminotransferase in tested cyanobacteria, and an N-succinyldiaminopimelate aminotransferase in tested actinobacteria and in the β-proteobacterium Nitrosomonas europaea. Recombinant PAT enzymes exhibit high activity toward prephenate, indicating that the corresponding genes encode bona fide PAT. PAT functionality was acquired without other modification of substrate specificity and is not a general catalytic property of the three classes of aminotransferases. PMID:24302739

  6. Substitution of apolar residues in the active site of aspartate aminotransferase by histidine. Effects on reaction and substrate specificity.

    PubMed

    Vacca, R A; Christen, P; Malashkevich, V N; Jansonius, J N; Sandmeier, E

    1995-01-15

    In an attempt to change the reaction and substrate specificity of aspartate aminotransferase, several apolar active-site residues were substituted in turn with a histidine residue. Aspartate aminotransferase W140H (of Escherichia coli) racemizes alanine seven times faster (Kcat' = 2.2 x 10(-4) s-1) than the wild-type enzyme, while the aminotransferase activity toward L-alanine was sixfold decreased. X-ray crystallographic analysis showed that the structural changes brought about by the mutation are limited to the immediate environment of H140. In contrast to the tryptophan side chain in the wild-type structure, the imidazole ring of H140 does not form a stacking interaction with the coenzyme pyridine ring. The angle between the two ring planes is about 50 degrees. Pyridoxamine 5'-phosphate dissociates 50 times more rapidly from the W140H mutant than from the wild-type enzyme. A model of the structure of the quinonoid enzyme substrate intermediate indicates that H140 might assist in the reprotonation of C alpha of the amino acid substrate from the re side of the deprotonated coenzyme-substrate adduct in competition with si-side reprotonation by K258. In aspartate aminotransferase I17H (of chicken mitochondria), the substituted residue also lies on the re side of the coenzyme. This mutant enzyme slowly decarboxylates L-aspartate to L-alanine (Kcat' = 8 x 10(-5) s-1). No beta-decarboxylase activity is detectable in the wild-type enzyme. In aspartate aminotransferase V37H (of chicken mitochondria), the mutated residue lies besides the coenzyme in the plane of the pyridine ring; no change in reaction specificity was observed. All three mutations, i.e. W140-->H, I17-->H and V37--H, decreased the aminotransferase activity toward aromatic amino acids by 10-100-fold, while decreasing the activity toward dicarboxylic substrates only moderately to 20%, 20% and 60% of the activity of the wild-type enzymes, respectively. In all three mutant enzymes, the decrease in aspartate

  7. Glutamate-1-semialdehyde aminotransferase from Sulfolobus solfataricus.

    PubMed

    Palmieri, G; Di Palo, M; Scaloni, A; Orru, S; Marino, G; Sannia, G

    1996-12-01

    Glutamate-1-semialdehyde aminotransferase (GSA-AT) from the extremely thermophilic bacterium Sulfolobus solfataricus has been purified to homogeneity and characterized. GSA-AT is the last enzyme in the C5 pathway for the conversion of glutamate into the tetrapyrrole precursor delta-aminolaevulinate (ALA) in plants, algae and several bacteria. The active form of GSA-AT from S. solfataricus seems to be a homodimer with a molecular mass of 87 kDa. The absorption spectrum of the purified aminotransferase is indicative of the presence of pyridoxamine 5'-phosphate (PMP) cofactor, and the catalytic activity of the enzyme is further stimulated by addition of PMP. 3-Amino-2,3-dihydrobenzoic acid is an inhibitor of the aminotransferase activity. The N-terminal amino acid sequence of GSA-AT from S. solfataricus was found to share significant similarity with the eukaryotic and eubacterial enzymes. Evidence is provided that ALA synthesis in S. solfataricus follows the C5 pathway characteristic of plants, algae, cyanobacteria and many other bacteria. PMID:8973563

  8. Effect of Hypericum perforatum Aqueous Extracts on Serum Lipids, Aminotransferases, and Lipid Peroxidation in Hyperlipidemic Rats

    PubMed Central

    Ghosian Moghaddam, Mohammad Hassan; Roghani, Mehrdad; Maleki, Maryam

    2016-01-01

    Background: Patients with high levels of total cholesterol (TCH), low-density lipoprotein cholesterol (LDL-CH), and triglyceride (TG) are at increased risk of coronary heart disease. Studies have shown that flavonoids and antioxidant compounds have beneficial effects on hyperlipidemia. Objectives: The aim of the present study was to evaluate the effects of extract of Hypericum perforatum (EHP) on the serum lipid profile (TCH, TG, and LDL-CH), aminotransferase, alkaline phosphatase, and lipid peroxidation in hyperlipidemic rats. Materials and Methods: Thirty-two male rats weighting 200 ± 10 g were randomly divided into four experimental groups: 1) control, 2) control + EHP, 3) hyperlipidemia, and 4) hyperlipidemia + EHP. The rats in the hyperlipidemic groups were fed a high-fat diet for 60 days, and EHP (300 mg/kg) was injected intraperitoneally for 2 weeks in the rats in the second and fourth groups. At the end of the experimental period, blood samples from each group were analyzed. Results: There was a significant reduction in LDL-CH in the control + EHP group and the hyperlipidemia + EHP group (P < 0.05). TCH was significantly reduced in the control + EHP group (P < 0.05). There were no significant changes in the levels of TG and HDL-CH. Malondialdehyde, aspartate aminotransferase, and alanine aminotransferase were significantly reduced in the hyperlipidemia + EHP group (P < 0.05), with no significant change in alkaline phosphatase. Conclusions: EHP was able to both reduce LDL-CH and to significantly decrease markers of oxidative stress and lipid peroxidation induced by hyperlipidemia. Therefore, this herb, as a new pharmacological component, could be used to reduce certain blood lipids, lipid peroxidation, and aminotransferase markers. PMID:26949689

  9. The reaction of ornithine aminotransferase with ornithine.

    PubMed Central

    Williams, J A; Bridge, G; Fowler, L J; John, R A

    1982-01-01

    Rat liver ornithine aminotransferase is found to exchange the pro-S hydrogen on the delta-carbon atom of ornithine exclusively, thus showing that the mammalian enzyme transfers the delta-amino group and not the alpha-amino group as has been demonstrated with the plant enzyme [Mestichelli, Gupta & Spenser (1979) J. Biol. Chem. 254, 640-647]. The enzyme also transfers the alpha-amino group of glutamate and the kinetics of the half reactions between the enzyme and both amino acids are compared. Rate and dissociation constants for both reactions are determined. PMID:6282258

  10. Comparison of effect of cafetière and filtered coffee on serum concentrations of liver aminotransferases and lipids: six month randomised controlled trial.

    PubMed Central

    Urgert, R.; Meyboom, S.; Kuilman, M.; Rexwinkel, H.; Vissers, M. N.; Klerk, M.; Katan, M. B.

    1996-01-01

    OBJECTIVE: To study the effects of prolonged intake of cafetière coffee, which is rich in the diterpenes cafestol and kahweol, on serum aminotransferase and lipid concentrations. DESIGN: Randomised parallel controlled trial. SUBJECTS: 46 healthy men and women aged 19 to 69. INTERVENTION: Consumption of five to six strong cups (0.9 litres) a day of either cafetière (22 subjects) or filtered coffee (24 subjects) for 24 weeks. MAIN OUTCOME MEASURES: Mean changes in serum aminotransferase and lipid concentrations. RESULTS: Cafetière coffee raised alanine aminotransferase concentration by up to 80% above baseline values relative to filtered coffee. After 24 weeks the rise was still 45% (9 U/l (95% confidence interval 3 to 15 U/l), P = 0.007). Alanine aminotransferase concentration exceeded the upper limit of normal in eight of the 22 subjects drinking cafetière coffee, being twice the upper limit of normal in three of them. Cafetière coffee raised low density lipoprotein cholesterol concentrations by 9-14%. After 24 weeks the rise was 0.26 mmol/l (0.04 to 0.47 mmol/l) (P = 0.03) relative to filtered coffee. Triglyceride concentrations initially rose by 26% with cafetière coffee but returned close to baseline values within six months. All increases were reversible after the intervention was stopped. CONCLUSIONS: Daily consumption of five to six cups of strong cafetière coffee affects the integrity of liver cells as suggested by small increases in serum alanine aminotransferase concentration. The effect does not subside with prolonged intake. High intakes of coffee brews rich in cafestol and kahweol may thus be responsible for unexplained increases in this enzyme activity in apparently healthy subjects. Cafetière coffee also raises low density lipoprotein cholesterol concentration and thus the risk of coronary heart disease. PMID:8956701

  11. Beta-alanine supplementation in high-intensity exercise.

    PubMed

    Harris, Roger C; Sale, Craig

    2012-01-01

    Glycolysis involves the oxidation of two neutral hydroxyl groups on each glycosyl (or glucosyl) unit metabolised, yielding two carboxylic acid groups. During low-intensity exercise these, along with the remainder of the carbon skeleton, are further oxidised to CO(2) and water. But during high-intensity exercise a major portion (and where blood flow is impaired, then most) is accumulated as lactate anions and H(+). The accumulation of H(+) has deleterious effects on muscle function, ultimately impairing force production and contributing to fatigue. Regulation of intracellular pH is achieved over time by export of H(+) out of the muscle, although physicochemical buffers in the muscle provide the first line of defence against H(+) accumulation. In order to be effective during high-intensity exercise, buffers need to be present in high concentrations in muscle and have pK(a)s within the intracellular exercise pH transit range. Carnosine (β-alanyl-L-histidine) is ideal for this role given that it occurs in millimolar concentrations within the skeletal muscle and has a pK(a) of 6.83. Carnosine is a cytoplasmic dipeptide formed by bonding histidine and β-alanine in a reaction catalysed by carnosine synthase, although it is the availability of β-alanine, obtained in small amounts from hepatic synthesis and potentially in greater amounts from the diet that is limiting to synthesis. Increasing muscle carnosine through increased dietary intake of β-alanine will increase the intracellular buffering capacity, which in turn might be expected to increase high-intensity exercise capacity and performance where this is pH limited. In this study we review the role of muscle carnosine as an H(+) buffer, the regulation of muscle carnosine by β-alanine, and the available evidence relating to the effects of β-alanine supplementation on muscle carnosine synthesis and the subsequent effects of this on high-intensity exercise capacity and performance. PMID:23075550

  12. Characterization of two aminotransferases from Candida albicans.

    PubMed

    Rząd, Kamila; Gabriel, Iwona

    2015-01-01

    Aminoadipate aminotransferase (AmAA) is an enzyme of α-aminoadipate pathway (AAP) for L-lysine biosynthesis. AmAA may also participated in biosynthesis or degradation of aromatic amino acids and in D-tryptophan based pigment production. The AAP is unique for fungal microorganisms. Enzymes involved in this pathway have specific structures and properties. These features can be used as potential molecular markers. Enzymes catalyzing reactions of L-lysine biosynthesis in Candida albicans may also become new targets for antifungal chemotherapy. Search of the NCBI database resulted in identification of two putative aminoadipate aminotransferase genes from Candida albicans: ARO8 (ORFs 19.2098 and 19.9645) and YER152C (ORFs 19.1180 and 19.8771). ARO8 from C. albicans exhibits 53% identity to ARO8 from S. cerevisiae, while YER152C exhibits 30% identity to ARO8 and 45% to YER152C from S. cerevisiae. We amplified two genes from the C. albicans genome: ARO8 and YER152C. Both were cloned and expressed as His-tagged fusion proteins in E. coli. The purified Aro8CHp gene product revealed aromatic and α-aminoadipate aminotransferase activity. Basic molecular properties of the purified protein were determined. We obtained catalytic parameters of Aro8CHp with aromatic amino acids and aminoadipate (AA) (Km(L-Phe) 0.05±0.003 mM, Km(L-Tyr) 0.1±0.008 mM, Km(L-AA) 0.02±0.006 mM) and confirmed the enzyme broad substrate spectrum. The assays also demonstrated that this enzyme may use 2-oxoadipate and 2-oxoglutarate (2-OG) as amino acceptors. Aro8-CHp exhibited pH optima range of 8, which is similar to AmAA from S. cerevisiae. Our results also indicate that CaYer152Cp has a possible role only in aromatic amino acids degradation, in contrast to CaAro8CHp. PMID:26619256

  13. Cumulative effects of mutations in newly synthesised mitochondrial aspartate aminotransferase on uptake into mitochondria.

    PubMed

    Marra, E; Azzariti, A; Giannattasio, S; Doonan, S; Quagliariello, E

    1995-09-14

    Mutant genes were constructed which coded for the precursor form of mitochondrial aspartate aminotransferase in which residue cysteine 166 was mutated to either serine or alanine and for forms of the protein lacking both the presequence and residues 1-9 of the mature protein but carrying the same cysteine mutations. The protein products of all of these mutant genes were imported into mitochondria that had been added to the expression system but with varying degrees of efficiency. The results showed that the effects of mutation of cysteine 166 and of deletion of residues 1-9 of the mature protein on sequestration into mitochondria were essentially cumulative, suggesting that these parts of the protein are involved in distinct steps on the recognition/uptake pathway. PMID:7677759

  14. Benign elevations in serum aminotransferases and biomarkers of hepatotoxicity in healthy volunteers treated with cholestyramine

    PubMed Central

    2014-01-01

    Background There are currently no serum biomarkers capable of distinguishing elevations in serum alanine aminotransferase (ALT) that portend serious liver injury potential from benign elevations such as those occurring during cholestyramine treatment. The aim of the research was to test the hypothesis that newly proposed biomarkers of hepatotoxicity would not significantly rise in serum during elevations in serum ALT associated with cholestyramine treatment, which has never been associated with clinically relevant liver injury. Methods In a double-blind placebo-controlled trial, cholestyramine (8g) was administered for 11 days to healthy adult volunteers. Serum from subjects with elevations in alanine aminotransferase (ALT) exceeding three-fold the upper limit of normal (ULN) were utilized for biomarker quantification. Results In 11 of 67 subjects, cholestyramine treatment resulted in ALT elevation by >3x ULN (mean 6.9 fold; range 3–28 fold). In these 11 subjects, there was a 22.4-fold mean increase in serum levels of miR-122 relative to baseline, supporting a liver origin of the serum ALT. Significant elevations were noted in mean levels of necrosis biomarkers sorbitol dehydrogenase (8.1 fold), cytokeratin 18 (2.1 fold) and HMGB1 (1.7 fold). Caspase-cleaved cytokeratin 18, a biomarker of apoptosis was also significantly elevated (1.7 fold). A rise in glutamate dehydrogenase (7.3 fold) may support mitochondrial dysfunction. Conclusion All toxicity biomarkers measured in this study were elevated along with ALT, confirming the liver origin and reflecting both hepatocyte necrosis and apoptosis. Since cholestyramine treatment has no clinical liver safety concerns, we conclude that interpretation of the biomarkers studied may not be straightforward in the context of assessing liver safety of new drugs. PMID:25086653

  15. Ornithine aminotransferase vs. GABA aminotransferase. Implications for the design of new anticancer drugs

    PubMed Central

    Lee, Hyunbeom; Juncosa, Jose I.; Silverman, Richard B.

    2015-01-01

    Ornithine aminotransferase (OAT) and γ-aminobutyric acid aminotransferase (GABA-AT) are classified under the same evolutionary subgroup and share a large portion of structural, functional, and mechanistic features. Therefore, it is not surprising that many molecules that bind to GABA-AT also bind well to OAT. Unlike GABA-AT, OAT had not been viewed as a potential therapeutic target until recently; consequently, the number of therapeutically viable molecules that target OAT is very limited. In this review the two enzymes are compared with respect to their active site structures, catalytic and inactivation mechanisms, and selective inhibitors. Insight is offered that could aid in the design and development of new selective inhibitors of OAT for the treatment of cancer. PMID:25145640

  16. Preoperative Aspartate Aminotransferase to White Blood Cell Count Ratio Predicting Postoperative Outcomes of Hepatocellular Carcinoma.

    PubMed

    Liao, Weijia; Wang, Yongqin; Liao, Yan; He, Songqing; Jin, Junfei

    2016-04-01

    Effective biomarkers for predicting prognosis of hepatocellular carcinoma (HCC) patients after hepatectomy is urgently needed. The purpose of this study is to evaluate the value of the preoperative peripheral aspartate aminotransferase to white blood cell count ratio (AWR) for the prognostication of patients with HCC.Clinical data of 396 HCC patients who underwent radical hepatectomy were retrospectively analyzed. The patients were divided into the low-AWR group (AWR ≤5.2) and the high-AWR group (AWR >5.2); univariate analysis, Kaplan-Meier method analysis, and the multivariate analysis by Cox regression were conducted, respectively.The results showed that AWR was associated with alpha-fetoprotein (AFP), tumor size, Barcelona clinic liver cancer (BCLC) stage, portal vein tumor thrombus (PVTT), and alanine aminotransferase (ALT) in HCC. AWR > 5.2, AFP > 100 ng/mL, size of tumor >6 cm, number of multiple tumors, B-C of BCLC stage, PVTT, and distant metastasis were predictors of poorer disease-free survival (DFS) and overall survival (OS). Except for recurrence, which was an independent predictor for OS only, AWR >5.2, size of tumor >6 cm, and PVTT were independent predictors of both DFS and OS.We concluded that preoperative AWR > 5.2 was an adverse predictor of DFS and OS in HCC after hepatectomy, AWR might be a novel prognostic biomarker in HCC after curative resection. PMID:27057915

  17. Liver aminotransferases and risk of incident type 2 diabetes: a systematic review and meta-analysis.

    PubMed

    Kunutsor, Setor K; Apekey, Tanefa A; Walley, John

    2013-07-15

    We evaluated the associations of liver aminotransferases with risk of type 2 diabetes (T2D) in general populations by conducting a systematic review and meta-analysis of published prospective studies. Studies were identified in a literature search of PubMed, EMBASE, and Web of Science from 1950 through October 2012. Of the 2,729 studies reviewed, 17 studies involving 60,359 participants and 3,890 incident T2D events were included. All of the studies assessed associations between alanine aminotransferase (ALT) level and T2D, with heterogeneous findings (I(2) = 88%, 95% confidence interval (CI): 82, 92; P < 0.001). The pooled fully adjusted relative risk of T2D was 1.26 (95% CI: 1.14, 1.41) per 1-standard-deviation change in log baseline ALT level. This association became nonsignificant after trim-and-fill correction for publication bias. Nine studies evaluated associations between aspartate aminotransferase (AST) levels and T2D risk, with a corresponding relative risk of 1.02 (95% CI: 0.99, 1.04). The relative risk of T2D per 5-IU/L increase in ALT level was 1.16 (95% CI: 1.08, 1.25). Available data indicate moderate associations of ALT with risk of T2D events, which may be attributable to publication bias. There was no evidence for an increased risk of T2D with AST. Large prospective studies may still be needed to establish the magnitude and nature of these associations. PMID:23729682

  18. 21 CFR 582.5118 - Alanine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5118 Alanine. (a) Product. Alanine...

  19. Physiological hypercortisolemia increases proteolysis, glutamine, and alanine production

    SciTech Connect

    Darmaun, D.; Matthews, D.E.; Bier, D.M. Cornell Univ. Medical College, New York, NY )

    1988-09-01

    Physiological elevations of plasma cortisol levels, as are encountered in stress and severe trauma, were produced in six normal subjects by infusing them with hydrocortisone for 64 h. Amino acid kinetics were measured in the postabsorptive state using three 4-h infusions of L-(1-{sup 13}C)leucine, L-phenyl({sup 2}H{sub 5})phenylalanine, L-(2-{sup 15}N)glutamine, and L-(1-{sup 13}C)alanine tracers (1) before, (2) at 12 h, and (3) at 60 h of cortisol infusion. Before and throughout the study, the subjects ate a normal diet of adequate protein and energy intake. The cortisol infusion raised plasma cortisol levels significantly from 10 {plus minus} 1 to 32 {plus minus} 4 {mu}g/dl, leucine flux from 83 {plus minus} 3 to 97 {plus minus} 3 {mu}mol{center dot}kg{sup {minus}1}{center dot}h{sup {minus}1}, and phenylalanine flux from 34 {plus minus} 1 to 39 {plus minus} 1 (SE) {mu}mol{center dot}kg{sup {minus}1}{center dot}h{sup {minus}1} after 12 h of cortisol infusion. These increases were maintained until the cortisol infusion was terminated. These nearly identical 15% increases in two different essential amino acid appearance rates are reflective of increased whole body protein breakdown. Glutamine flux rose by 12 h of cortisol infusion and remained elevated at the same level at 64 h. The increase in flux was primarily due to a 55% increase in glutamine de novo synthesis. Alanine flux increased with acute hypercortisolemia and increased further at 60 h of cortisol infusion, a result primarily of increased alanine de novo synthesis. Insulin, alanine, and lactate plasma levels responded similarly with significant rises between the acute and chronic periods of cortisol infusion. Thus hypercortisolemia increases both protein breakdown and the turnover of important nonessential amino acids for periods of up to 64 h.

  20. Structure of tyrosine aminotransferase from Leishmania infantum

    PubMed Central

    Moreno, M. A.; Abramov, A.; Abendroth, J.; Alonso, A.; Zhang, S.; Alcolea, P. J.; Edwards, T.; Lorimer, D.; Myler, P. J.; Larraga, V.

    2014-01-01

    The trypanosomatid parasite Leishmania infantum is the causative agent of visceral leishmaniasis (VL), which is usually fatal unless treated. VL has an incidence of 0.5 million cases every year and is an important opportunistic co-infection in HIV/AIDS. Tyrosine aminotransferase (TAT) has an important role in the metabolism of trypanosomatids, catalyzing the first step in the degradation pathway of aromatic amino acids, which are ultimately converted into their corresponding l-2-oxoacids. Unlike the enzyme in Trypanosoma cruzi and mammals, L. infantum TAT (LiTAT) is not able to transaminate ketoglutarate. Here, the structure of LiTAT at 2.35 Å resolution is reported, and it is confirmed that the presence of two Leishmania-specific residues (Gln55 and Asn58) explains, at least in part, this specific reactivity. The difference in substrate specificity between leishmanial and mammalian TAT and the importance of this enzyme in parasite metabolism suggest that it may be a useful target in the development of new drugs against leishmaniasis. PMID:24817714

  1. Crystal Structure of Human Kynurenine Aminotransferase ll*

    SciTech Connect

    Han,Q.; Robinson, H.; Li, J.

    2008-01-01

    Human kynurenine aminotransferase II (hKAT-II) efficiently catalyzes the transamination of knunrenine to kynurenic acid (KYNA). KYNA is the only known endogenous antagonist of N-methyl-d-aspartate (NMDA) receptors and is also an antagonist of 7-nicotinic acetylcholine receptors. Abnormal concentrations of brain KYNA have been implicated in the pathogenesis and development of several neurological and psychiatric diseases in humans. Consequently, enzymes involved in the production of brain KYNA have been considered potential regulatory targets. In this article, we report a 2.16 Angstroms crystal structure of hKAT-II and a 1.95 Angstroms structure of its complex with kynurenine. The protein architecture of hKAT-II reveals that it belongs to the fold-type I pyridoxal 5-phosphate (PLP)-dependent enzymes. In comparison with all subclasses of fold-type I-PLP-dependent enzymes, we propose that hKAT-II represents a novel subclass in the fold-type I enzymes because of the unique folding of its first 65 N-terminal residues. This study provides a molecular basis for future effort in maintaining physiological concentrations of KYNA through molecular and biochemical regulation of hKAT-II.

  2. Lactate Racemization as a Rescue Pathway for Supplying d-Lactate to the Cell Wall Biosynthesis Machinery in Lactobacillus plantarum

    PubMed Central

    Goffin, Philippe; Deghorain, Marie; Mainardi, Jean-Luc; Tytgat, Isabelle; Champomier-Vergès, Marie-Christine; Kleerebezem, Michiel; Hols, Pascal

    2005-01-01

    Lactobacillus plantarum is a lactic acid bacterium that produces d- and l-lactate using stereospecific NAD-dependent lactate dehydrogenases (LdhD and LdhL, respectively). However, reduction of glycolytic pyruvate by LdhD is not the only pathway for d-lactate production since a mutant defective in this activity still produces both lactate isomers (T. Ferain, J. N. Hobbs, Jr., J. Richardson, N. Bernard, D. Garmyn, P. Hols, N. E. Allen, and J. Delcour, J. Bacteriol. 178:5431-5437, 1996). Production of d-lactate in this species has been shown to be connected to cell wall biosynthesis through its incorporation as the last residue of the muramoyl-pentadepsipeptide peptidoglycan precursor. This particular feature leads to natural resistance to high concentrations of vancomycin. In the present study, we show that L. plantarum possesses two pathways for d-lactate production: the LdhD enzyme and a lactate racemase, whose expression requires l-lactate. We report the cloning of a six-gene operon, which is involved in lactate racemization activity and is positively regulated by l-lactate. Deletion of this operon in an L. plantarum strain that is devoid of LdhD activity leads to the exclusive production of l-lactate. As a consequence, peptidoglycan biosynthesis is affected, and growth of this mutant is d-lactate dependent. We also show that the growth defect can be partially restored by expression of the d-alanyl-d-alanine-forming Ddl ligase from Lactococcus lactis, or by supplementation with various d-2-hydroxy acids but not d-2-amino acids, leading to variable vancomycin resistance levels. This suggests that L. plantarum is unable to efficiently synthesize peptidoglycan precursors ending in d-alanine and that the cell wall biosynthesis machinery in this species is specifically dedicated to the production of peptidoglycan precursors ending in d-lactate. In this context, the lactate racemase could thus provide the bacterium with a rescue pathway for d-lactate production upon

  3. Kynurenine Aminotransferase Isozyme Inhibitors: A Review

    PubMed Central

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S.; Church, W. Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1–4) are members of the pyridoxal-5’-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  4. Kynurenine Aminotransferase Isozyme Inhibitors: A Review.

    PubMed

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S; Church, W Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1-4) are members of the pyridoxal-5'-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  5. Aspartate Aminotransferase in Alfalfa Root Nodules 1

    PubMed Central

    Farnham, Mark W.; Griffith, Stephen M.; Miller, Susan S.; Vance, Carroll P.

    1990-01-01

    Aspartate aminotransferase (AAT) plays an important role in nitrogen metabolism in all plants and is particularly important in the assimilation of fixed N derived from the legume-Rhizoblum symbiosis. Two isozymes of AAT (AAT-1 and AAT-2) occur in alfalfa (Medicago sativa L.). Antibodies against alfalfa nodule AAT-2 do not recognize AAT-1, and these antibodies were used to study AAT-2 expression in different tissues and genotypes of alfalfa and also in other legume and nonlegume species. Rocket immunoelectrophoresis indicated that nodules of 38-day-old alfalfa plants contained about eight times more AAT-2 than did nodules of 7-day-old plants, confirming the nodule-enhanced nature of this isozyme. AAT-2 was estimated to make up 16, 15, 5, and 8 milligrams per gram of total soluble protein in mature nodules, roots, stems, and leaves, respectively, of effective N2-fixing alfalfa. The concentration of AAT-2 in nodules of ineffective non-N2-fixing alafalfa genotypes was about 70% less than that of effective nodules. Western blots of soluble protein from nodules of nine legume species indicated that a 40-kilodalton polypeptide that reacts strongly with AAT-2 antibodies is conserved in legumes. Nodule AAT-2 immunoprecipitation data suggested that amide- and ureide-type legumes may differ in expression and regulation of the enzyme. In addition, Western blotting and immunoprecipitations of AAT activity demonstrated that antibodies against alfalfa AAT-2 are highly cross-reactive with AAT enzyme protein in leaves of soybean (Glycine max L.), wheat (Triticum aestivum L.), and maize (Zea mays L.) and in roots of maize, but not with AAT in soybean and wheat roots. Results from this study indicate that AAT-2 is structurally conserved and localized in similar tissues among diverse species. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:16667896

  6. Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci.

    PubMed

    Peralta, Guillermo Hugo; Bergamini, Carina Viviana; Hynes, Erica Rut

    2016-01-01

    Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in twenty one strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including fifteen mesophilic lactobacilli, four thermophilic lactobacilli, and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor. PMID:27266631

  7. Biochemical and structural characterization of mouse mitochondrial aspartate aminotransferase, a newly identified kynurenine aminotransferase-IV

    SciTech Connect

    Han, Q.; Robinson, H.; Cai, T.; Tagle, D. A.; Li, J.

    2011-10-01

    Mammalian mAspAT (mitochondrial aspartate aminotransferase) is recently reported to have KAT (kynurenine aminotransferase) activity and plays a role in the biosynthesis of KYNA (kynurenic acid) in rat, mouse and human brains. This study concerns the biochemical and structural characterization of mouse mAspAT. In this study, mouse mAspAT cDNA was amplified from mouse brain first stand cDNA and its recombinant protein was expressed in an Escherichia coli expression system. Sixteen oxo acids were tested for the co-substrate specificity of mouse mAspAT and 14 of them were shown to be capable of serving as co-substrates for the enzyme. Structural analysis of mAspAT by macromolecular crystallography revealed that the cofactor-binding residues of mAspAT are similar to those of other KATs. The substrate-binding residues of mAspAT are slightly different from those of other KATs. Our results provide a biochemical and structural basis towards understanding the overall physiological role of mAspAT in vivo and insight into controlling the levels of endogenous KYNA through modulation of the enzyme in the mouse brain.

  8. Substrate Specificity and Structure of Human Aminoadipate Aminotransferase/kynurenine Aminotransferase II

    SciTech Connect

    Han,Q.; Cai, T.; Tagle, D.; Robinson, H.; Li, J.

    2008-01-01

    KAT (kynurenine aminotransferase) II is a primary enzyme in the brain for catalysing the transamination of kynurenine to KYNA (kynurenic acid). KYNA is the only known endogenous antagonist of the N-methyl-D-aspartate receptor. The enzyme also catalyses the transamination of aminoadipate to a-oxoadipate; therefore it was initially named AADAT (aminoadipate aminotransferase). As an endotoxin, aminoadipate influences various elements of glutamatergic neurotransmission and kills primary astrocytes in the brain. A number of studies dealing with the biochemical and functional characteristics of this enzyme exist in the literature, but a systematic assessment of KAT II addressing its substrate profile and kinetic properties has not been performed. The present study examines the biochemical and structural characterization of a human KAT II/AADAT. Substrate screening of human KAT II revealed that the enzyme has a very broad substrate specificity, is capable of catalysing the transamination of 16 out of 24 tested amino acids and could utilize all 16 tested a-oxo acids as amino-group acceptors. Kinetic analysis of human KAT II demonstrated its catalytic efficiency for individual amino-group donors and acceptors, providing information as to its preferred substrate affinity. Structural analysis of the human KAT II complex with a-oxoglutaric acid revealed a conformational change of an N-terminal fraction, residues 15-33, that is able to adapt to different substrate sizes, which provides a structural basis for its broad substrate specificity.

  9. Substrate Specificity and Structure of Human aminoadipate aminotransferase/kynurenine aminotransferase II

    SciTech Connect

    Han, Q.; Cai, T; Tagle, D; Robinson, H; Li, J

    2009-01-01

    KAT (kynurenine aminotransferase) II is a primary enzyme in the brain for catalysing the transamination of kynurenine to KYNA (kynurenic acid). KYNA is the only known endogenous antagonist of the N-methyl-D-aspartate receptor. The enzyme also catalyses the transamination of aminoadipate to alpha-oxoadipate; therefore it was initially named AADAT (aminoadipate aminotransferase). As an endotoxin, aminoadipate influences various elements of glutamatergic neurotransmission and kills primary astrocytes in the brain. A number of studies dealing with the biochemical and functional characteristics of this enzyme exist in the literature, but a systematic assessment of KAT II addressing its substrate profile and kinetic properties has not been performed. The present study examines the biochemical and structural characterization of a human KAT II/AADAT. Substrate screening of human KAT II revealed that the enzyme has a very broad substrate specificity, is capable of catalysing the transamination of 16 out of 24 tested amino acids and could utilize all 16 tested alpha-oxo acids as amino-group acceptors. Kinetic analysis of human KAT II demonstrated its catalytic efficiency for individual amino-group donors and acceptors, providing information as to its preferred substrate affinity. Structural analysis of the human KAT II complex with alpha-oxoglutaric acid revealed a conformational change of an N-terminal fraction, residues 15-33, that is able to adapt to different substrate sizes, which provides a structural basis for its broad substrate specificity.

  10. Inhibitors of alanine racemase enzyme: a review.

    PubMed

    Azam, Mohammed Afzal; Jayaram, Unni

    2016-08-01

    Alanine racemase is a fold type III PLP-dependent amino acid racemase enzyme catalysing the conversion of l-alanine to d-alanine utilised by bacterial cell wall for peptidoglycan synthesis. As there are no known homologs in humans, it is considered as an excellent antibacterial drug target. The standard inhibitors of this enzyme include O-carbamyl-d-serine, d-cycloserine, chlorovinyl glycine, alaphosphin, etc. d-Cycloserine is indicated for pulmonary and extra pulmonary tuberculosis but therapeutic use of drug is limited due to its severe toxic effects. Toxic effects due to off-target affinities of cycloserine and other substrate analogs have prompted new research efforts to identify alanine racemase inhibitors that are not substrate analogs. In this review, an updated status of known inhibitors of alanine racemase enzyme has been provided which will serve as a rich source of structural information and will be helpful in generating selective and potent inhibitor of alanine racemase. PMID:26024289

  11. A randomized, placebo-controlled trial to determine the course of aminotransferase elevation during prolonged acetaminophen administration

    PubMed Central

    2014-01-01

    Background Acetaminophen administration for more than 4 days causes aminotransferase elevation in some subjects. The objective of this randomized, placebo-controlled trial is to describe the course of alanine aminotransferase (ALT) elevation in subjects administered 4 g/day of acetaminophen for at least 16 days. Methods A randomized, placebo controlled trial of acetaminophen (4 g/day) vs placebo. Subjects were healthy volunteers with normal liver enzymes. The primary outcome was the course of ALT during acetaminophen administration. All subjects were treated for a minimum of 16 days. Subjects with ALT elevation at day 16 were continued on treatment until these elevations resolved up to a maximum of 40 days. Subjects were also evaluated for elevation of INR or serum bilirubin as evidence of hepatic dysfunction. Results 157/205 (77%) completed acetaminophen subjects had no ALT elevation or transient elevations that resolved by day 16. Of the 48 subjects who had ALT elevations at study day 16, 47 continued on acetaminophen and had resolution by study day 40. One acetaminophen subject did not have resolution by study day 40, and the course of aminotransferase elevation suggests an alternative cause. One placebo subject had an ALT elevation at day 16 that resolved by day 22. The highest observed ALT among all acetaminophen subjects was 191 IU/L. The mean ALT at day 16 was 4.4 IU/L higher for the acetaminophen than for the placebo group. No subject developed liver dysfunction. Conclusions A minority of subjects treated with 4 g/day of acetaminophen for 16 days will have low-grade aminotransferase elevations that are not accompanied by liver dysfunction and resolve if administration is continued. Trials registration Clintrials.gov NCT00743093 registered August 26, 2008 PMID:25047090

  12. Elevation of Serum Aminotransferase Levels and Future Risk of Death from External Causes: A Prospective Cohort Study in Korea

    PubMed Central

    Sohn, Jungwoo; Kang, Dae Ryong; Kim, Hyeon Chang; Cho, Jaelim; Choi, Yoon Jung; Suh, Il

    2015-01-01

    Purpose The association between liver enzymes and death from external causes has not been examined. We investigated the association between serum aminotransferase levels and external-cause mortality in a large prospective cohort study. Materials and Methods A total of 142322 subjects of 35-59 years of age who completed baseline examinations in 1990 and 1992 were enrolled. Mortalities were identified using death certificates. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were categorized into quintiles. Sub-distribution hazards ratios and 95% confidence intervals (CIs) were estimated using a competing risks regression model in which deaths from other causes were treated as competing risks. Results Of 8808 deaths, 1111 (12.6%) were due to external causes. Injury accounted for 256 deaths, and suicide accounted for 255. After adjusting for covariates, elevated ALT and AST were significantly associated with an increased risk of all external-cause mortalities, as well as suicide and injury. Sub-distribution hazards ratios (95% CIs) of the highest versus the lowest quintiles of serum ALT and AST were, respectively, 1.57 (1.26-1.95) and 1.45 (1.20-1.76) for all external causes, 2.73 (1.68-4.46) and 1.75 (1.15-2.66) for suicide, and 1.79 (1.10-2.90) and 1.85 (1.21-2.82) for injury. The risk of external-cause mortality was also significantly higher in the fourth quintile of ALT (21.6-27.5 IU/L) than in its first quintile. Conclusion Elevated aminotransferase levels, even within the normal range, were significantly associated with increased risk of all external-cause mortalities, including suicide, and injury. PMID:26446640

  13. Comparison of blood aminotransferase methods for assessment of myopathy and hepatopathy in Florida manatees (Trichechus manatus latirostris).

    PubMed

    Harr, Kendal E; Allison, Kathryn; Bonde, Robert K; Murphy, David; Harvey, John W

    2008-06-01

    Muscle injury is common in Florida manatees (Trichechus manatus latirostris). Plasma aspartate aminotransferase (AST) is frequently used to assess muscular damage in capture myopathy and traumatic injury. Therefore, accurate measurement of AST and alanine aminotransferase (ALT) is important in managed, free-ranging animals, as well as in those rehabilitating from injury. Activities of these enzymes, however, are usually not increased in manatees with either acute or chronic muscle damage, despite marked increases in plasma creatine kinase activity. It is hypothesized that this absence of response is due to apoenzymes in the blood not detected by commonly used veterinary assays. Addition of coenzyme pyridoxal-5-phosphate (P5P or vitamin B6) should, therefore, result in higher measured enzyme activities. The objective of this study was to determine the most accurate, precise, and diagnostically useful method for aminotransferase measurement in manatees that can be used in veterinary practices and diagnostic laboratories. Additionally, appropriate collection and storage techniques were assessed. The use of an optimized commercial wet chemical assay with 100 micromol P5P resulted in a positive bias of measured enzyme activities in a healthy population of animals. However, AST and ALT were still much lower than that typically observed in domestic animals and should not be used alone in the assessment of capture myopathy and muscular trauma. Additionally, the dry chemistry analyzer, typically used in clinics, reported significantly higher and less precise AST and ALT activities with poor correlation to those measured with wet chemical methods found in diagnostic laboratories. Therefore, these results cannot be clinically compared. Overall, the optimized wet chemical method was the most precise and diagnostically useful measurement of aminotransferase in samples. Additionally, there was a statistically significant difference between paired serum and plasma measurement

  14. Vibrational dynamics of crystalline L-alanine

    SciTech Connect

    Bordallo, H.N.; Eckert, J.; Barthes, M.

    1997-11-01

    The authors report a new, complete vibrational analysis of L-alanine and L-alanine-d{sub 4} which utilizes IINS intensities in addition to frequency information. The use of both isotopomers resulted in a self-consistent force field for and assignment of the molecular vibrations in L-alanine. Some details of the calculation as well as a comparison of calculated and observed IINS spectra are presented. The study clarifies a number of important issues on the vibrational dynamics of this molecule and presents a self-consistent force field for the molecular vibrations in crystalline L-alanine.

  15. Catalytic Stereoinversion of L-Alanine to Deuterated D-Alanine.

    PubMed

    Moozeh, Kimia; So, Soon Mog; Chin, Jik

    2015-08-01

    A combination of an achiral pyridoxal analogue and a chiral base has been developed for catalytic deuteration of L-alanine with inversion of stereochemistry to give deuterated D-alanine under mild conditions (neutral pD and 25 °C) without the use of any protecting groups. This system can also be used for catalytic deuteration of D-alanine with retention of stereochemistry to give deuterated D-alanine. Thus a racemic mixture of alanine can be catalytically deuterated to give an enantiomeric excess of deuterated D-alanine. While catalytic deracemization of alanine is forbidden by the second law of thermodynamics, this system can be used for catalytic deracemization of alanine with deuteration. Such green and biomimetic approach to catalytic stereocontrol provides insights into efficient amino acid transformations. PMID:26119066

  16. The effect of beta-alanine supplementation on isokinetic force and cycling performance in highly trained cyclists.

    PubMed

    Howe, Samuel T; Bellinger, Phillip M; Driller, Matthew W; Shing, Cecilia M; Fell, James W

    2013-12-01

    Beta-alanine may benefit short-duration, high-intensity exercise performance. The aim of this randomized double-blind placebo-controlled study was to examine the effects of beta-alanine supplementation on aspects of muscular performance in highly trained cyclists. Sixteen highly trained cyclists (mean ± SD; age = 24 ± 7 yr; mass = 70 ± 7 kg; VO2max = 67 ± 4 ml · kg(-1) · min(-1)) supplemented with either beta-alanine (n = 8, 65 mg · kg - 1BM) or a placebo (n = 8; dextrose monohydrate) over 4 weeks. Pre- and postsupplementation cyclists performed a 4-minute maximal cycling test to measure average power and 30 reciprocal maximal isokinetic knee contractions at a fixed angular velocity of 180° · sec(-1) to measure average power/repetition, total work done (TWD), and fatigue index (%). Blood pH, lactate (La-) and bicarbonate (HCO3-) concentrations were measured pre- and postisokinetic testing at baseline and following the supplementation period. Beta-alanine supplementation was 44% likely to increase average power output during the 4-minute cycling time trial when compared with the placebo, although this was not statistically significant (p = .25). Isokinetic average power/repetition was significantly increased post beta-alanine supplementation compared with placebo (beta-alanine: 6.8 ± 9.9 W, placebo: -4.3 ± 9.5 W, p = .04, 85% likely benefit), while fatigue index was significantly reduced (p = .03, 95% likely benefit). TWD was 89% likely to be improved following beta-alanine supplementation; however, this was not statistically significant (p = .09). There were no significant differences in blood pH, lactate, and HCO3- between groups (p > .05). Four weeks of beta-alanine supplementation resulted in worthwhile changes in time-trial performance and short-duration muscular force production in highly trained cyclists. PMID:23630052

  17. Functional Characterization of Alanine Racemase from Schizosaccharomyces pombe: a Eucaryotic Counterpart to Bacterial Alanine Racemase

    PubMed Central

    Uo, Takuma; Yoshimura, Tohru; Tanaka, Naotaka; Takegawa, Kaoru; Esaki, Nobuyoshi

    2001-01-01

    Schizosaccharomyces pombe has an open reading frame, which we named alr1+, encoding a putative protein similar to bacterial alanine racemase. We cloned the alr1+ gene in Escherichia coli and purified the gene product (Alr1p), with an Mr of 41,590, to homogeneity. Alr1p contains pyridoxal 5′-phosphate as a coenzyme and catalyzes the racemization of alanine with apparent Km and Vmax values as follows: for l-alanine, 5.0 mM and 670 μmol/min/mg, respectively, and for d-alanine, 2.4 mM and 350 μmol/min/mg, respectively. The enzyme is almost specific to alanine, but l-serine and l-2-aminobutyrate are racemized slowly at rates 3.7 and 0.37% of that of l-alanine, respectively. S. pombe uses d-alanine as a sole nitrogen source, but deletion of the alr1+ gene resulted in retarded growth on the same medium. This indicates that S. pombe has catabolic pathways for both enantiomers of alanine and that the pathway for l-alanine coupled with racemization plays a major role in the catabolism of d-alanine. Saccharomyces cerevisiae differs markedly from S. pombe: S. cerevisiae uses l-alanine but not d-alanine as a sole nitrogen source. Moreover, d-alanine is toxic to S. cerevisiae. However, heterologous expression of the alr1+ gene enabled S. cerevisiae to grow efficiently on d-alanine as a sole nitrogen source. The recombinant yeast was relieved from the toxicity of d-alanine. PMID:11244061

  18. The retarded hair growth (rhg) mutation in mice is an allele of ornithine aminotransferase (Oat)

    PubMed Central

    Bisaillon, Jason J.; Radden, Legairre A.; Szabo, Eric T.; Hughes, Samantha R.; Feliciano, Aaron M.; Nesta, Alex V.; Petrovic, Belinda; Palanza, Kenneth M.; Lancinskas, Dainius; Szmurlo, Theodore A.; Artus, David C.; Kapper, Martin A.; Mulrooney, James P.; King, Thomas R.

    2014-01-01

    Because of the similar phenotypes they generate and their proximate reported locations on Chromosome 7, we tested the recessive retarded hair growth (rhg) and frizzy (fr) mouse mutations for allelism, but found instead that these defects complement. To discover the molecular basis of rhg, we analyzed a large intraspecific backcross panel that segregated for rhg and restricted this locus to a 0.9 Mb region that includes fewer than ten genes, only five of which have been reported to be expressed in skin. Complementation testing between rhg and a recessive null allele of fibroblast growth factor receptor 2 eliminated Fgfr2 as the possible basis of the retarded hair growth phenotype, but DNA sequencing of another of these candidates, ornithine aminotransferase (Oat), revealed a G to C transversion specifically associated with the rhg allele that would result in a glycine to alanine substitution at residue 353 of the gene product. To test whether this missense mutation might cause the mutant phenotype, we crossed rhg/rhg mice with mice that carried a recessive, perinatal-lethal, null mutation in Oat (designated OatΔ herein). Hybrid offspring that inherited both rhg and OatΔ displayed markedly delayed postnatal growth and hair development, indicating that these two mutations are allelic, and suggesting strongly that the G to C mutation in Oat is responsible for the retarded hair growth phenotype. Comparisons among +/+, rhg/+, rhg/rhg and rhg/OatΔ mice showed plasma ornithine levels and ornithine aminotransferase activities (in liver lysates) consistent with this assignment. Because histology of 7- and 12-month-old rhg/rhg and rhg/OatΔ retinas revealed chorioretinal degeneration similar to that described previously for OatΔ/OatΔ mice, we suggest that the rhg mutant may offer an ideal model for gyrate atrophy of the choroid and retina (GACR) in humans, which is also caused by the substitution of glycine 353 in some families. PMID:25264521

  19. Lactation and reproduction*

    PubMed Central

    Thomson, A. M.; Hytten, F. E.; Black, A. E.

    1975-01-01

    The authors review the literature on the effect of lactation on fertility in the absence of contraception and on the effects of contraceptive measures on lactation. They examine data from several countries on the intervals between births and on the return of menstruation and ovulation after childbirth, comparing lactating with nonlactating women. They conclude that lactation is an inefficient contraceptive for the individual, but that in populations sustained lactation is associated with reduced fertility. Possible physiological mechanisms causing lactation amenorrhoea are discussed. Though much of the literature on the effect of contraceptives on lactation is inadequate, there is general agreement that the estrogen component of hormonal preparations has an adverse effect on lactation, but that progestins alone do not. Many questions remain. Is this effect seen in established lactation, or only in the puerperal period? Is it a direct pharmacological effect, or are pill-users the mothers least motivated to maintain breast-feeding? Does a close relationship exist between hormones given and lactation performance? The authors comment on some of the technical deficiencies of previous studies in this field and discuss practical possibilities of, and limitations to, obtaining adequate scientific information in the future. PMID:1084804

  20. Elevated Serum Aminotransferases Secondary to Rippling Muscle Disease

    PubMed Central

    Nalankilli, Kumanan; Lubel, John

    2013-01-01

    A 43-year-old man was referred by his general practitioner to the hepatology clinic with deranged serum aminotransferases, discovered as part of routine blood tests. The objective was to identify the cause of elevated serum aminotransferases in this patient in a systematic manner. Thorough history and physical examination revealed a background history of rippling muscle disease secondary to caveolin-3 protein deficiency, with typical clinical signs. There was a positive family history of musculoskeletal disease in the patient's father and brother. Previous diagnostic tests performed to investigate the patient's musculoskeletal symptoms, including muscle biopsies, were revisited. Subsequent systematic investigations such as blood tests, liver ultrasound scan and Fibroscan® were performed to exclude potential causes of the deranged serum aminotransferases. Liver biopsy was not performed. A consistent pattern of chronic low-grade elevations of serum aminotransferases, less than three times the upper limit of the normal range, was found. This was associated with a consistently elevated serum creatine kinase and normal renal function tests. Previous muscle biopsies had revealed chronic degenerative and regenerative changes suggestive of a focal necrotizing myopathy. Liver ultrasound scan and Fibroscan® were normal. With exclusion of other liver diseases and identification of profoundly elevated serum creatine kinase concentration, the deranged aminotransferases were attributed to rippling muscle disease. PMID:23798914

  1. Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

    NASA Technical Reports Server (NTRS)

    Weber, A. L.

    1985-01-01

    The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

  2. Detection of intracellular lactate with localized diffusion { 1H- 13C}-spectroscopy in rat glioma in vivo

    NASA Astrophysics Data System (ADS)

    Pfeuffer, Josef; Lin, Joseph C.; DelaBarre, Lance; Ugurbil, Kamil; Garwood, Michael

    2005-11-01

    The aim of this study was to compare the diffusion characteristic of lactate and alanine in a brain tumor model to that of normal brain metabolites known to be mainly intracellular such as N-acetylaspartate or creatine. The diffusion of 13C-labeled metabolites was measured in vivo with localized NMR spectroscopy at 9.4 T (400 MHz) using a previously described localization and editing pulse sequence known as ACED-STEAM ('adiabatic carbon editing and decoupling'). 13C-labeled glucose was administered and the apparent diffusion coefficients of the glycolytic products, { 1H- 13C}-lactate and { 1H- 13C}-alanine, were determined in rat intracerebral 9L glioma. To obtain insights into { 1H- 13C}-lactate compartmentation (intra- versus extracellular), the pulse sequence used very large diffusion weighting (50 ms/μm 2). Multi-exponential diffusion attenuation of the lactate metabolite signals was observed. The persistence of a lactate signal at very large diffusion weighting provided direct experimental evidence of significant intracellular lactate concentration. To investigate the spatial distribution of lactate and other metabolites, 1H spectroscopic images were also acquired. Lactate and choline-containing compounds were consistently elevated in tumor tissue, but not in necrotic regions and surrounding normal-appearing brain. Overall, these findings suggest that lactate is mainly associated with tumor tissue and that within the time-frame of these experiments at least some of the glycolytic product ([ 13C] lactate) originates from an intracellular compartment.

  3. Cloning and nucleotide sequencing of Rhizobium meliloti aminotransferase genes: an aspartate aminotransferase required for symbiotic nitrogen fixation is atypical.

    PubMed Central

    Watson, R J; Rastogi, V K

    1993-01-01

    In Rhizobium meliloti, an aspartate aminotransferase (AspAT) encoded within a 7.3-kb HindIII fragment was previously shown to be required for symbiotic nitrogen fixation and aspartate catabolism (V. K. Rastogi and R.J. Watson, J. Bacteriol. 173:2879-2887, 1991). A gene coding for an aromatic aminotransferase located within an 11-kb HindIII fragment was found to complement the AspAT deficiency when overexpressed. The genes encoding these two aminotransferases, designated aatA and tatA, respectively, have been localized by subcloning and transposon Tn5 mutagenesis. Sequencing of the tatA gene revealed that it encodes a protein homologous to an Escherichia coli aromatic aminotransferase and most of the known AspAT enzymes. However, sequencing of the aatA gene region revealed two overlapping open reading frames, neither of which encoded an enzyme with homology to the typical AspATs. Polymerase chain reaction was used to selectively generate one of the candidate sequences for subcloning. The cloned fragment complemented the original nitrogen fixation and aspartate catabolism defects and was shown to encode an AspAT with the expected properties. Sequence analysis showed that the aatA protein has homology to AspATs from two thermophilic bacteria and the eukaryotic tyrosine aminotransferases. These aminotransferases form a distinct class in which only 13 amino acids are conserved in comparison with the well-known AspAT family. DNA homologous to the aatA gene was found to be present in Agrobacterium tumefaciens and other rhizobia but not in Klebsiella pneumoniae or E. coli. Images PMID:8096210

  4. Transhepatic lactate gradient in relation to liver ischemia/reperfusion injury during major hepatectomies.

    PubMed

    Theodoraki, Kassiani; Arkadopoulos, Nikolaos; Fragulidis, George; Voros, Dionysios; Karapanos, Konstantinos; Markatou, Maria; Kostopanagiotou, Georgia; Smyrniotis, Vassilios

    2006-12-01

    Hepatectomies performed under selective hepatic vascular exclusion are associated with a series of events culminating in ischemia/reperfusion injury, a state that shares common characteristics with situations known to result in global or regional hyperlactatemia. Accordingly, we sought to determine whether lactate is released by the liver during hepatic resections performed under blood flow deprivation and what relation this has to a possible systemic hyperlactatemic state. After ethical approval, 14 consecutive patients with resectable liver tumors subjected to hepatectomy under inflow and outflow occlusion of the liver were studied. Lactate concentrations were assessed in simultaneously drawn arterial, portal venous, and hepatic venous blood before liver dissection and 50 minutes postreperfusion. Moreover, the transhepatic lactate gradient (hepatic vein - portal vein) was calculated to see if there was net production or consumption of lactate. Before hepatic dissection, the transhepatic lactate gradient was negative, suggesting consumption by the liver. Fifty minutes after reperfusion, this gradient became significantly positive, demonstrating release of lactate by the liver (0.12 +/- 0.31 vs. -0.38 +/- 0.30 mmol/L, P < 0.05). The magnitude of lactate release correlated with systemic arterial lactate levels at the same time point (r(2) = 0.63, P < 0.001). A weaker but significant correlation was demonstrated between the transhepatic lactate gradient postreperfusion and systemic arterial lactate levels 24 hours postoperatively (r(2) = 0.41, P = 0.013). A strong correlation between the transhepatic lactate gradient postreperfusion and peak postoperative aspartate aminotransferase values was also demonstrated (r(2) = 0.73, P < 0.001). The liver becomes a net producer of lactate in hepatectomies performed under blood flow deprivation. This lactate release can explain some of the systemic hyperlactatemia seen in this context and relates to the extent of ischemia

  5. Physiology of lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The breast changes in size, shape, and function during puberty, pregnancy, and lactation. The physiology of lactation is reviewed here. The breast is composed of fat and connective tissue that supports a tubuloalveolar structure. During development, anatomic changes involving new lobule formation an...

  6. Kinetic properties and thermal stabilities of mutant forms of mitochondrial aspartate aminotransferase.

    PubMed

    Azzariti, A; Vacca, R A; Giannattasio, S; Merafina, R S; Marra, E; Doonan, S

    1998-07-28

    Kinetic properties and thermal stabilities of the precursor form of mitochondrial aspartate aminotransferase, the mature form lacking 9 amino acids from the N-terminus, and forms of the mature protein in which cysteine-166 had been mutated to serine or alanine were compared with those of the mature enzyme. The precursor and the cysteine mutants showed moderately impaired catalytic properties consistent with decreased ability to undergo transition from the open to the closed conformation which is an integral part of the mechanism of action of the enzyme. The deletion mutant had a kcat only 2% of that of the mature enzyme but also much reduced Km values for both substrates. In addition it showed enhanced reactivity of cysteine-166 with 5,5'-dithiobis(2-nitrobenzoate), which is characteristic of the closed form of the enzyme, with no enhancement of reactivity in the presence of substrates. This is taken to show that the deletion mutant adopts a conformation that is significantly different from that of the mature enzyme particularly in respect of the small domain. The deletion mutant was found to be more resistant to thermal inactivation over a range of temperatures than were the other forms of the enzyme consistent with its having a more tightly packed small domain. PMID:9675237

  7. Hematological and biochemical findings in pregnant, postfoaling, and lactating jennies.

    PubMed

    Bonelli, F; Rota, A; Corazza, M; Serio, D; Sgorbini, M

    2016-04-15

    The aims of this study were to (1) verify if significant changes occur in hematological and biochemical parameters in jennies during the last 2 months of pregnancy and the first 2 months of lactation, and (2) determine any differences with mares. Hematological and biochemical parameters were evaluated in jennies every 15 days during late pregnancy, parturition, and early lactation. The Kolmogorov-Smirnov test, analysis of variance for repeated measurements and Tukey's multiple comparison test as post hoc were applied. The significance level was set at P < 0.05. Statistical analysis showed differences related to time for Red Blood Cells (RBC) count and Hematocrit (HCT), White Blood Cells (WBC) count, platelet count (PLT), total proteins, blood urea, triglycerides and total cholesterol concentrations, aspartate aminotransferase, gamma-glutamyltransferase, creatine-phosphokinase activities, sodium (Na) and potassium (K). RBC and HCT were higher in late pregnancy than at foaling and during lactation. The relative anemia might be due to increased water ingestion because of fluid losses. The WBC count was higher at foaling than during late pregnancy and lactation. This could be related to the release of cortisol and catecholamine during delivery. The PLT trend showed lower values from delivery to the first 2 months of lactation compared to late gestation. Blood urea increased near parturition, and then remained constant during delivery and lactation, which might be due to the high energy demand at the beginning of lactation. Triglycerides and total cholesterol showed a decrease from delivery through the lactation period. Thus, jennies seem to have a similar metabolism of fats to ponies and draft horse mares, characterized by a greater fat content and mobilization than light breed horses. Aspartate aminotransferase activity decreased at parturition and early lactation, probably because of a predominance of anabolic over catabolic processes during pregnancy. Gamma

  8. Requirement for alanine in the amino acid control of deprivation-induced protein degradation in liver.

    PubMed Central

    Pösö, A R; Mortimore, G E

    1984-01-01

    Protein degradation in liver is actively controlled by a small group of inhibitory amino acids--leucine, tyrosine (or phenylalanine), glutamine, proline, histidine, tryptophan, and methionine. Other evidence, however, suggests that one or more of the remaining 12 noninhibitory amino acids is also required for suppression of proteolysis at normal concentrations. This question was investigated in livers of fed rats perfused in the single-pass mode. The deletion of alanine at normal (1x), but not at 4x or 10x normal, plasma amino acid concentrations evoked a near-maximal acceleration of protein degradation. No other noninhibitory amino acid was effective. Because alanine alone was not directly inhibitory and its omission was not associated with a decrease in inhibitory amino acid pools, alanine was presumed to act as a coregulator in the expression of inhibitory activity. When tested alone, the inhibitory group was as effective as the complete mixture at 0.5x and 4x levels, but it lost its suppressive ability within a narrow zone of concentration centered slightly above 1x. The addition of 1x (0.48 mM) alanine completely restored the inhibition. Pyruvate and lactate could be effectively substituted, but only at concentrations 10-20 times greater than that of alanine. These, together with earlier findings, indicate the existence of a regulatory complex that recognizes specific amino acids and transmits positive and negative signals to proteolytic sites. The results also suggest that alanine can provide an important regulatory link between energy demands and protein degradation. PMID:6589593

  9. The effect of β-alanine supplementation on cycling time trials of different length.

    PubMed

    Bellinger, Phillip M; Minahan, Clare L

    2016-10-01

    The varying results reported in response to β-alanine supplementation may be related to the duration and nature of the exercise protocol employed. We investigated the effects of β-alanine supplementation on a wide range of cycling performance tests in order to produce a clear concise set of criteria for its efficacy. Fourteen trained cyclists (Age = 24.8 ± 6.7 years; VO2max = 65.4 ± 10.2 mL·kg·min(-1)) participated in this placebo-controlled, double-blind study. Prior to supplementation, subjects completed two (familiarization and baseline) supramaximal cycling bouts until exhaustion (120% pre-supplementation VO2max) and two 1-, 4- and 10-km cycling time trial (TT). Subjects then supplemented orally for 4 weeks with 6.4 g/d placebo or β-alanine and repeated the battery of performance tests. Blood lactate was measured pre-exercise, post-exercise and 5  min post-exercise. β-alanine supplementation elicited significant increases in time to exhaustion (TTE) (17.6 ± 11.5 s; p = 0.013, effect compared with placebo) and was likely to be beneficial to 4-km TT performance time (-7.8 ± 8.1 s; 94% likelihood), despite not being statistically different (p = 0.060). Performance times in the 1- and 10-km TT were not affected by treatment. For the highly trained cyclists in the current study, β-alanine supplementation significantly extended supramaximal cycling TTE and may have provided a worthwhile improvement to 4-km TT performance. However, 1- and 10-km cycling TT performance appears to be unaffected by β-alanine supplementation. PMID:26652037

  10. Human milk nonprotein nitrogen components: changing patterns of free amino acids and urea in the course of early lactation.

    PubMed

    Harzer, G; Franzke, V; Bindels, J G

    1984-08-01

    Free amino acids and urea were analyzed in 78 human milk samples obtained during the first 5 wk of lactation from 10 mothers delivering at term. Significant differences (p less than 0.05) in the concentrations between colostral and mature milk were found for glutamic acid, glutamine, alanine, glycine, cystine, and phosphoethanolamine which increased, and with serine, phosphoserine, aspartic acid + asparagine, arginine, lysine, isoleucine, phenylalanine, proline, methionine, tryptophan, and beta-alanine which decreased. Some of these changes occurred within the first 5 days of lactation, so that differences between transitional and mature milk became negligible (glutamic acid, alanine, and serine, aspartic acid + asparagine, lysine, isoleucine, methionine, tryptophan, respectively). No significant differences between any of the three stages of lactation were found regarding the concentrations of total free amino acids, urea, taurine, threonine, valine, leucine, histidine, and tyrosine. Possible relevances for free amino acids, including nonprotein ones, in human milk are discussed. PMID:6147084

  11. Tracer studies on the biosynthesis of amino acids from lactate by Peptostreptococcus elsdenii

    PubMed Central

    Somerville, H. J.; Peel, J. L.

    1967-01-01

    Peptostreptococcus elsdenii, a strict anaerobe from the rumen, was grown on a medium containing yeast extract and [1-14C]- or [2-14C]-lactate. Radioisotope from lactate was found in all cell fractions, but mainly in the protein. The label in the protein fraction was largely confined to a few amino acids: alanine, serine, aspartic acid, glutamic acid and diaminopimelic acid. The alanine, serine, aspartic acid and glutamic acid were separated, purified and degraded to establish the distribution of 14C from lactate within the amino acid molecules. The labelling patterns in alanine and serine suggested their formation from lactate without cleavage of the carbon chain. The pattern in aspartic acid suggested formation by condensation of a C3 unit derived directly from lactate with a C1 unit, probably carbon dioxide. The distribution in glutamic acid was consistent with two possible pathways of formation: (a) by the reactions of the tricarboxylic acid cycle leading from oxaloacetate to 2-oxoglutarate, followed by transamination; (b) by a pathway involving the reaction sequence 2 acetyl-CoA→crotonyl-CoA→glutaconate→glutamate. PMID:6069834

  12. [Psychopharmacotherapy in pregnancy and lactation. 2: Lactation].

    PubMed

    Lanczik, M; Knoche, M; Fritze, J

    1998-01-01

    Whilst the incidence of psychiatric disorders decreases during pregnancy, the risk during the postpartum period increases significantly, often leading to the necessity of psychopharmacological intervention during the puerperium, and subsequently during lactation and breast-feeding. The necessity for lithium prophylaxis in manic-depressive women after childbirth has been identified, and it is recommended that weaning rather than omission of psychopharmacological treatment is preferable during the puerperium. PMID:9522328

  13. Recombinant expression of twelve evolutionarily diverse subfamily Iα aminotransferases

    PubMed Central

    Muratore, Kathryn E.; Srouji, John R.; Chow, Margaret A.; Kirsch, Jack F.

    2009-01-01

    Aminotransferases are essential enzymes involved in the central metabolism of all organisms. The Iα subfamily of aspartate and tyrosine aminotransferases (AATases and TATases) is the best-characterized grouping, but only eight enzymes from this subfamily, representing relatively little sequence diversity, have been experimentally characterized for substrate specificity (i.e., AATase vs. TATase). Genome annotation, based on this limited dataset, provides tentative assignments for all sequenced members of this subfamily. This procedure is, however, subject to error, particularly when the experimental basis set is limited. To address this problem we cloned twelve additional subfamily Iα enzymes from an evolutionarily divergent set of organisms. Nine were purified to homogeneity after heterologous expression in E. coli in native, intein-tagged or His6-tagged forms and the two S. cerevisiae isoforms were recombinantly produced in yeast. The effects of the C-terminal tags on expression, purification and enzyme activity are discussed. PMID:17964807

  14. Comparison of blood aminotransferase methods for assessment of myopathy and hepatopathy in Florida manatees (Trichechus manatus latirostris)

    USGS Publications Warehouse

    Harr, K.E.; Allison, K.; Bonde, R.K.; Murphy, D.; Harvey, J.W.

    2008-01-01

    Muscle injury is common in Florida manatees (Trichechus manatus latirostris). Plasma aspartate amino-transferase (AST) is frequently used to assess muscular damage in capture myopathy and traumatic injury. Therefore, accurate measurement of AST and alanine aminotransferase (ALT) is important in managed, free-ranging animals, as well as in those rehabilitating from injury. Activities of these enzymes, however, are usually not increased in manatees with either acute or chronic muscle damage, despite marked increases in plasma creatine kinase activity. It is hypothesized that this absence of response is due to apoenzymes in the blood not detected by commonly used veterinary assays. Addition of coenzyme pyridoxal-5-phosphate (P5P or vitamin B6) should, therefore, result in higher measured enzyme activities. The objective of this study was to determine the most accurate, precise, and diagnostically useful method for aminotransferase measurement in manatees that can be used in veterinary practices and diagnostic laboratories. Additionally, appropriate collection and storage techniques were assessed. The use of an optimized commercial wet chemical assay with 100 ??mol P5P resulted in a positive bias of measured enzyme activities in a healthy population of animals. However, AST and ALT were still much lower than that typically observed in domestic animals and should not be used alone in the assessment of capture myopathy and muscular trauma. Additionally, the dry chemistry analyzer, typically used in clinics, reported significantly higher and less precise AST and ALT activities with poor correlation to those measured with wet chemical methods found in diagnostic laboratories. Therefore, these results cannot be clinically compared. Overall, the optimized wet chemical method was the most precise and diagnostically useful measurement of aminotransferase in samples. Additionally, there was a statistically significant difference between paired serum and plasma measurement

  15. Correlation between HIV viral load and aminotransferases as liver damage markers in HIV infected naive patients: a concordance cross-sectional study

    PubMed Central

    Mata-Marín, José Antonio; Gaytán-Martínez, Jesús; Grados-Chavarría, Bernardo Horacio; Fuentes-Allen, José Luis; Arroyo-Anduiza, Carla Ileana; Alfaro-Mejía, Alfredo

    2009-01-01

    Abnormalities in liver function tests could be produced exclusively by direct inflammation in hepatocytes, caused by the human immunodeficiency virus (HIV). Mechanisms by which HIV causes hepatic damage are still unknown. Our aim was to determine the correlation between HIV viral load, and serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) as markers of hepatic damage in HIV naive infected patients. We performed a concordance cross-sectional study. Patients with antiviral treatment experience, hepatotoxic drugs use or co-infection were excluded. We used a Pearson's correlation coefficient to calculate the correlation between aminotransferases serum levels with HIV viral load. We enrolled 59 patients, 50 men and 9 women seen from 2006 to 2008. The mean (± SD) age of our subjects was 34.24 ± 9.5, AST 37.73 ± 29.94 IU/mL, ALT 43.34 ± 42.41 IU/mL, HIV viral load 199,243 ± 292,905 copies/mL, and CD4+ cells count 361 ± 289 cells/mm3. There was a moderately strong, positive correlation between AST serum levels and HIV viral load (r = 0.439, P < 0.001); and a weak correlation between ALT serum levels and HIV viral load (r = 0.276, P = 0.034); after adjusting the confounders in lineal regression model the correlation remained significant. Our results suggest that there is an association between HIV viral load and aminotransferases as markers of hepatic damage; we should improved recognition, diagnosis and potential therapy of hepatic damage in HIV infected patients. PMID:19878552

  16. Correlation between HIV viral load and aminotransferases as liver damage markers in HIV infected naive patients: a concordance cross-sectional study.

    PubMed

    Mata-Marín, José Antonio; Gaytán-Martínez, Jesús; Grados-Chavarría, Bernardo Horacio; Fuentes-Allen, José Luis; Arroyo-Anduiza, Carla Ileana; Alfaro-Mejía, Alfredo

    2009-01-01

    Abnormalities in liver function tests could be produced exclusively by direct inflammation in hepatocytes, caused by the human immunodeficiency virus (HIV). Mechanisms by which HIV causes hepatic damage are still unknown. Our aim was to determine the correlation between HIV viral load, and serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) as markers of hepatic damage in HIV naive infected patients. We performed a concordance cross-sectional study. Patients with antiviral treatment experience, hepatotoxic drugs use or co-infection were excluded. We used a Pearson's correlation coefficient to calculate the correlation between aminotransferases serum levels with HIV viral load. We enrolled 59 patients, 50 men and 9 women seen from 2006 to 2008. The mean (+/- SD) age of our subjects was 34.24 +/- 9.5, AST 37.73 +/- 29.94 IU/mL, ALT 43.34 +/- 42.41 IU/mL, HIV viral load 199,243 +/- 292,905 copies/mL, and CD4+ cells count 361 +/- 289 cells/mm(3). There was a moderately strong, positive correlation between AST serum levels and HIV viral load (r = 0.439, P < 0.001); and a weak correlation between ALT serum levels and HIV viral load (r = 0.276, P = 0.034); after adjusting the confounders in lineal regression model the correlation remained significant. Our results suggest that there is an association between HIV viral load and aminotransferases as markers of hepatic damage; we should improved recognition, diagnosis and potential therapy of hepatic damage in HIV infected patients. PMID:19878552

  17. 21 CFR 582.5118 - Alanine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  18. 21 CFR 582.5118 - Alanine.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  19. 21 CFR 582.5118 - Alanine.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  20. 21 CFR 582.5118 - Alanine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  1. Lactate: Friend or Foe.

    PubMed

    Hall, Mederic M; Rajasekaran, Sathish; Thomsen, Timothy W; Peterson, Andrew R

    2016-03-01

    Lactic acid has played an important role in the traditional theory of muscle fatigue and limitation of endurance exercise performance. It has been called a waste product of anaerobic metabolism and has been believed to be responsible for the uncomfortable "burn" of intense exercise and directly responsible for the metabolic acidosis of exercise, leading to decreased muscle contractility and ultimately cessation of exercise. Although this premise has been commonly taught, it is not supported by the scientific literature and has led to a great deal of confusion among the sports medicine and exercise science communities. This review will provide the sports medicine clinician with an understanding of contemporary lactate theories, including lactate's role in energy production, its contributions to metabolic acidosis, and its function as an energy substrate for a variety of tissues. Lactate threshold concepts will also be discussed, including a practical approach to understanding prediction of performance and monitoring of training progress based on these parameters. PMID:26972271

  2. [Aspartate aminotransferase--key enzyme in the human systemic metabolism].

    PubMed

    Otto-Ślusarczyk, Dagmara; Graboń, Wojciech; Mielczarek-Puta, Magdalena

    2016-01-01

    Aspartate aminotransferase is an organ-nonspecific enzyme located in many tissues of the human body where it catalyzes reversible reaction of transamination. There are two aspartate aminotransferase isoforms--cytoplasmic (AST1) and mitochondrial (AST2), that usually occur together and interact with each other metabolically. Both isoforms are homodimers containing highly conservative regions responsible for catalytic properties of enzyme. The common feature of all aspartate aminotransfeses is Lys - 259 residue covalent binding with prosthetic group - pyridoxal phosphate. The differences in the primary structure of AST isoforms determine their physico-chemical, kinetic and immunological properties. Because of the low concentration of L-aspartate (L-Asp) in the blood, AST is the only enzyme, which supply of this amino acid as a substrate for many metabolic processes, such as urea cycle or purine and pyrimidine nucleotides in the liver, synthesis of L-arginine in the kidney and purine nucleotide cycle in the brain and the skeletal muscle. AST is also involved in D-aspartate production that regulates the metabolic activity at the auto-, para- and endocrine level. Aspartate aminotransferase is a part of the malate-aspartate shuttle in the myocardium, is involved in gluconeogenesis in the liver and kidney, glyceroneogenesis in the adipose tissue, and synthesis of neurotransmitters and neuro-glial pathway in the brain. Recently, the significant role of AST in glutaminolysis - normal metabolic pathway in tumor cells, was demonstrated. The article is devoted the role of AST, known primarily as a diagnostic liver enzyme, in metabolism of various human tissues and organs. PMID:27117097

  3. Concerted modulation of alanine and glutamate metabolism in young Medicago truncatula seedlings under hypoxic stress

    PubMed Central

    Limami, Anis M.; Glévarec, Gaëlle; Ricoult, Claudie; Cliquet, Jean-Bernard; Planchet, Elisabeth

    2008-01-01

    The modulation of primary nitrogen metabolism by hypoxic stress was studied in young Medicago truncatula seedlings. Hypoxic seedlings were characterized by the up-regulation of glutamate dehydrogenase 1 (GDH1) and mitochondrial alanine aminotransferase (mAlaAT), and down-regulation of glutamine synthetase 1b (GS1b), NADH-glutamate synthase (NADH-GOGAT), glutamate dehydrogenase 3 (GDH3), and isocitrate dehydrogenase (ICDH) gene expression. Hypoxic stress severely inhibited GS activity and stimulated NADH-GOGAT activity. GDH activity was lower in hypoxic seedlings than in the control, however, under either normoxia or hypoxia, the in vivo activity was directed towards glutamate deamination. 15NH4 labelling showed for the first time that the adaptive reaction of the plant to hypoxia consisted of a concerted modulation of nitrogen flux through the pathways of both alanine and glutamate synthesis. In hypoxic seedlings, newly synthesized 15N-alanine increased and accumulated as the major amino acid, asparagine synthesis was inhibited, while 15N-glutamate was synthesized at a similar rate to that in the control. A discrepancy between the up-regulation of GDH1 expression and the down-regulation of GDH activity by hypoxic stress highlighted for the first time the complex regulation of this enzyme by hypoxia. Higher rates of glycolysis and ethanol fermentation are known to cause the fast depletion of sugar stores and carbon stress. It is proposed that the expression of GDH1 was stimulated by hypoxia-induced carbon stress, while the enzyme protein might be involved during post-hypoxic stress contributing to the regeneration of 2-oxoglutarate via the GDH shunt. PMID:18508812

  4. Metabolic consequences of β-alanine supplementation during exhaustive supramaximal cycling and 4000-m time-trial performance.

    PubMed

    Bellinger, Phillip M; Minahan, Clare L

    2016-08-01

    The present study investigated the effects of β-alanine supplementation on the resultant blood acidosis, lactate accumulation, and energy provision during supramaximal-intensity cycling, as well as the aerobic and anaerobic contribution to power output during a 4000-m cycling time trial (TT). Seventeen trained cyclists (maximal oxygen uptake = 4.47 ± 0.55 L·min(-1)) were administered 6.4 g of β-alanine (n = 9) or placebo (n = 8) daily for 4 weeks. Participants performed a supramaximal cycling test to exhaustion (equivalent to 120% maximal oxygen uptake) before (PreExh) and after (PostExh) the 4-week supplementation period, as well as an additional postsupplementation supramaximal cycling test identical in duration and power output to PreExh (PostMatch). Anaerobic capacity was quantified and blood pH, lactate, and bicarbonate concentrations were measured pre-, immediately post-, and 5 min postexercise. Subjects also performed a 4000-m cycling TT before and after supplementation while the aerobic and anaerobic contributions to power output were quantified. β-Alanine supplementation increased time to exhaustion (+12.8 ± 8.2 s; P = 0.041) and anaerobic capacity (+1.1 ± 0.7 kJ; P = 0.048) in PostExh compared with PreExh. Performance time in the 4000-m TT was reduced following β-alanine supplementation (-6.3 ± 4.6 s; P = 0.034) and the mean anaerobic power output was likely to be greater (+6.2 ± 4.5 W; P = 0.035). β-Alanine supplementation increased time to exhaustion concomitant with an augmented anaerobic capacity during supramaximal intensity cycling, which was also mirrored by a meaningful increase in the anaerobic contribution to power output during a 4000-m cycling TT, resulting in an enhanced overall performance. PMID:27467218

  5. Effects of diets containing grape seed, linseed, or both on milk production traits, liver and kidney activities, and immunity of lactating dairy ewes.

    PubMed

    Nudda, A; Correddu, F; Marzano, A; Battacone, G; Nicolussi, P; Bonelli, P; Pulina, G

    2015-02-01

    This study aimed to evaluate the effects of the dietary inclusion of grape seed, alone or in combination with linseed, on milk production traits, immune response, and liver and kidney metabolic activity of lactating ewes. Twenty-four Sarda dairy ewes were randomly assigned to 4 dietary treatments consisting of a control diet (CON), a diet containing 300 g/d per head of grape seed (GS), a diet containing 220 g/d per head of extruded linseed (LIN), and a diet containing a mix of 300 g/d per head of grape seed and 220 g/d per head of extruded linseed (MIX). The study lasted 10 wk, with 2 wk of adaptation period and 8 wk of experimental period. Milk yield was measured and samples were collected weekly and analyzed for fat, protein, casein, lactose, pH, milk urea nitrogen, and somatic cell count. Blood samples were collected every 2 wk by jugular vein puncture and analyzed for hematological parameters, for albumin, alkaline phosphatase, bilirubin, creatinine, gamma glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, protein, blood urea nitrogen, and for anti-albumin IgG, IL-6, and lymphocyte T-helper (CD4(+)) and lymphocyte T-cytotoxic (CD8(+)) cells. On d 0, 45, and 60 of the trial, lymphocyte response to phytohemagglutinin was determined in vivo on each animal by measuring skin-fold thickness (SFT) at the site of phytohemagglutinin injection. Humoral response to chicken egg albumin was stimulated by a subcutaneous injection with albumin. Dietary treatments did not affect milk yield and composition. Milk urea nitrogen and lactose were affected by diet × period. Diets did not influence hematological, kidney, and liver parameters, except for blood urea nitrogen, which decreased in LIN and increased in MIX compared with CON and GS. Dietary treatments did not alter CD4(+), CD8(+), and CD4(+)-to-CD8(+) ratio. The SFT was reduced in GS and MIX and increased in LIN compared with CON. The IgG and IL-6 were affected by diet × period. The reduction in Ig

  6. Serum aminotransferase ratio is independently correlated with hepatosteatosis in patients with HCV: a cross-sectional observational study

    PubMed Central

    Lin, Ming-Shyan; Lin, Huang-Shen; Chung, Chang-Ming; Lin, Yu-Sheng; Chen, Mei-Yen; Chen, Po-Han; Hu, Jing-Hong; Chou, Wen-Nan; Huang, Jui-Chu; Huang, Tung-Jung

    2015-01-01

    Objectives The incidence of non-alcoholic fatty liver disease (NAFLD) is significant in hepatitis C virus (HCV) carriers due to multiple mechanisms, and this worsens the progression of chronic liver diseases, such as cirrhosis and hepatocellular carcinoma, and death. The purpose of this study was to examine whether the alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio correlates with the status of hepatosteatosis. Design A cross-sectional observational study. Setting Community-based annual examination in northern Taiwan. Participants A total of 1354 participants (age 20 years or over) were enrolled after excluding participants with HCV seronegative, laboratory or questionnaires loss, moderate alcohol consumption, liver cirrhosis, tumours and postlobectomy. Outcome measures Fatty liver was diagnosed according to echogenic findings. NAFLD included grades 1–3 fatty liver and high-degree NAFLD defined grades 2–3 fatty liver. Results 580 males and 774 females with a mean age of 47.2 (SD=16.1) years were cross-sectionally studied. The participants with NAFLD have significantly higher levels of ALT/AST ratio, fasting glucose, triglyceride and systolic/diastolic blood pressure than non-NAFLD participants. The association between NAFLD and ALT/AST was significant even when adjusting for the metabolic syndrome (aOR 1.90; 95% CI 1.37 to 2.65; p<0.001). In patients with a high degree of NAFLD, the ALT/AST ratio was still a significant predictor for hepatosteatosis (aOR 2.44; 95% CI 1.58 to 3.77; p<0.001). Conclusions The ALT/AST ratio could be a strong risk of hepatosteatosis in patients with chronic HCV infection. PMID:26369802

  7. Biocatalytic potential of vanillin aminotransferase from Capsicum chinense

    PubMed Central

    2014-01-01

    Background The conversion of vanillin to vanillylamine is a key step in the biosynthetic route towards capsaicinoids in pungent cultivars of Capsicum sp. The reaction has previously been annotated to be catalysed by PAMT (putative aminotransferase; [GenBank: AAC78480.1, Swiss-Prot: O82521]), however, the enzyme has previously not been biochemically characterised in vitro. Results The biochemical activity of the transaminase was confirmed by direct measurement of the reaction with purified recombinant enzyme. The enzyme accepted pyruvate, and oxaloacetate but not 2-oxoglutarate as co-substrate, which is in accordance with other characterised transaminases from the plant kingdom. The enzyme was also able to convert (S)-1-phenylethylamine into acetophenone with high stereo-selectivity. Additionally, it was shown to be active at a broad pH range. Conclusions We suggest PAMT to be renamed to VAMT (vanillin aminotransferase, abbreviation used in this study) as formation of vanillin from vanillylamine could be demonstrated. Furthermore, due to high stereoselectivity and activity at physiological pH, VAMT is a suitable candidate for biocatalytic transamination in a recombinant whole-cell system. PMID:24712445

  8. Characterization of aromatic aminotransferases from Ephedra sinica Stapf.

    PubMed

    Kilpatrick, Korey; Pajak, Agnieszka; Hagel, Jillian M; Sumarah, Mark W; Lewinsohn, Efraim; Facchini, Peter J; Marsolais, Frédéric

    2016-05-01

    Ephedra sinica Stapf (Ephedraceae) is a broom-like shrub cultivated in arid regions of China, Korea and Japan. This plant accumulates large amounts of the ephedrine alkaloids in its aerial tissues. These analogs of amphetamine mimic the actions of adrenaline and stimulate the sympathetic nervous system. While much is known about their pharmacological properties, the mechanisms by which they are synthesized remain largely unknown. A functional genomics platform was established to investigate their biosynthesis. Candidate enzymes were obtained from an expressed sequence tag collection based on similarity to characterized enzymes with similar functions. Two aromatic aminotransferases, EsAroAT1 and EsAroAT2, were characterized. The results of quantitative reverse transcription-polymerase chain reaction indicated that both genes are expressed in young stem tissue, where ephedrine alkaloids are synthesized, and in mature stem tissue. Nickel affinity-purified recombinant EsAroAT1 exhibited higher catalytic activity and was more homogeneous than EsAroAT2 as determined by size-exclusion chromatography. EsAroAT1 was highly active as a tyrosine aminotransferase with α-ketoglutarate followed by α-ketomethylthiobutyrate and very low activity with phenylpyruvate. In the reverse direction, catalytic efficiency was similar for the formation of all three aromatic amino acids using L-glutamate. Neither enzyme accepted putative intermediates in the ephedrine alkaloid biosynthetic pathway, S-phenylacetylcarbinol or 1-phenylpropane-1,2-dione, as substrates. PMID:26832171

  9. Alanine transport across in vitro rabbit vagina.

    PubMed

    Hajjar, J J; Mroueh, A M

    1979-04-01

    Transmural flux of alanine across the vaginal epithelium of the rabbit is a specialized mechanism. There is a net serosal to mucosal translocation of the amino acid in the absence of a concentration gradient. Changes in reproductive cycle do not influence this mechanism but, in castrated animals, it is abolished. Transport properties of vaginal epithelium is important because of increasing utilization of intravaginal contraceptives. PMID:455986

  10. Earthworms accumulate alanine in response to drought.

    PubMed

    Holmstrup, Martin; Slotsbo, Stine; Henriksen, Per G; Bayley, Mark

    2016-09-01

    Earthworms have ecologically significant functions in tropical and temperate ecosystems and it is therefore important to understand how these animals survive during drought. In order to explore the physiological responses to dry conditions, we simulated a natural drought incident in a laboratory trial exposing worms in slowly drying soil for about one month, and then analyzed the whole-body contents of free amino acids (FAAs). We investigated three species forming estivation chambers when soils dry out (Aporrectodea tuberculata, Aporrectodea icterica and Aporrectodea longa) and one species that does not estivate during drought (Lumbricus rubellus). Worms subjected to drought conditions (< -2MPa) substantially increased the concentration of FAAs and in particular alanine that was significantly upregulated in all tested species. Alanine was the most important FAA reaching 250-650μmolg(-1) dry weight in dehydrated Aporrectodea species and 300μmolg(-1) dry weight in L. rubellus. Proline was only weakly upregulated in some species as were a few other FAAs. Species forming estivation chambers (Aporrectodea spp.) did not show a better ability to conserve body water than the non-estivating species (L. rubellus) at the same drought level. These results suggest that the accumulation of alanine is an important adaptive trait in drought tolerance of earthworms in general. PMID:27107492

  11. Ornithine delta-aminotransferase mutations in gyrate atrophy. Allelic heterogeneity and functional consequences.

    PubMed

    Brody, L C; Mitchell, G A; Obie, C; Michaud, J; Steel, G; Fontaine, G; Robert, M F; Sipila, I; Kaiser-Kupfer, M; Valle, D

    1992-02-15

    Ornithine delta-aminotransferase is a nuclear-encoded mitochondrial matrix enzyme which catalyzes the reversible interconversion of ornithine and alpha-ketoglutarate to glutamate semialdehyde and glutamate. Inherited deficiency of ornithine delta-aminotransferase results in ornithine accumulation and a characteristic chorioretinal degeneration, gyrate atrophy of the choroid and retina. We have surveyed the ornithine delta-aminotransferase genes of gyrate atrophy patients for mutations. Using a variety of techniques, we discovered and molecularly characterized 21 newly recognized ornithine delta-aminotransferase alleles. We determined the consequences of these and three previously described mutations on ornithine delta-aminotransferase mRNA, antigen, and enzyme activity in cultured fibroblasts. The majority (20/24) of these alleles produce normal amounts of normally sized ornithine delta-aminotransferase mRNA. By contrast, only 2/24 had normal amounts of ornithine delta-aminotransferase antigen. Reproducing these mutations by site-directed mutagenesis and expressing the mutant ornithine delta-aminotransferase in Chinese hamster ovary cells confirms that several of these mutations inactivate ornithine delta-aminotransferase and cause gyrate atrophy in these patients. PMID:1737786

  12. Alcohol's effect on lactation.

    PubMed

    Mennella, J

    2001-01-01

    Although pregnant women are discouraged from drinking alcohol because of alcohol's detrimental effect on fetal development, the lore of many cultures encourages lactating women to drink alcohol to optimize breast milk production and infant nutrition. In contrast to this folklore, however, studies demonstrate that maternal alcohol consumption may slightly reduce milk production. Furthermore, some of the alcohol consumed by a lactating woman is transferred to her milk and thus consumed by the infant. This alcohol consumption may adversely affect the infant's sleep and gross motor development and influence early learning about alcohol. Based on this science, it would seem that the recommendation for a nursing mother to drink a glass of beer or wine shortly before nursing may actually be counterproductive. PMID:11810962

  13. Catabolism of Exogenous Lactate Reveals It as a Legitimate Metabolic Substrate in Breast Cancer

    PubMed Central

    Kennedy, Kelly M.; Scarbrough, Peter M.; Ribeiro, Anthony; Richardson, Rachel; Yuan, Hong; Sonveaux, Pierre; Landon, Chelsea D.; Chi, Jen-Tsan; Pizzo, Salvatore

    2013-01-01

    Lactate accumulation in tumors has been associated with metastases and poor overall survival in cancer patients. Lactate promotes angiogenesis and metastasis, providing rationale for understanding how it is processed by cells. The concentration of lactate in tumors is a balance between the amount produced, amount carried away by vasculature and if/how it is catabolized by aerobic tumor or stromal cells. We examined lactate metabolism in human normal and breast tumor cell lines and rat breast cancer: 1. at relevant concentrations, 2. under aerobic vs. hypoxic conditions, 3. under conditions of normo vs. hypoglucosis. We also compared the avidity of tumors for lactate vs. glucose and identified key lactate catabolites to reveal how breast cancer cells process it. Lactate was non-toxic at clinically relevant concentrations. It was taken up and catabolized to alanine and glutamate by all cell lines. Kinetic uptake rates of lactate in vivo surpassed that of glucose in R3230Ac mammary carcinomas. The uptake appeared specific to aerobic tumor regions, consistent with the proposed “metabolic symbiont” model; here lactate produced by hypoxic cells is used by aerobic cells. We investigated whether treatment with alpha-cyano-4-hydroxycinnamate (CHC), a MCT1 inhibitor, would kill cells in the presence of high lactate. Both 0.1 mM and 5 mM CHC prevented lactate uptake in R3230Ac cells at lactate concentrations at ≤20 mM but not at 40 mM. 0.1 mM CHC was well-tolerated by R3230Ac and MCF7 cells, but 5 mM CHC killed both cell lines ± lactate, indicating off-target effects. This study showed that breast cancer cells tolerate and use lactate at clinically relevant concentrations in vitro (± glucose) and in vivo. We provided additional support for the metabolic symbiont model and discovered that breast cells prevailingly take up and catabolize lactate, providing rationale for future studies on manipulation of lactate catabolism pathways for therapy. PMID:24069390

  14. Aspartate aminotransferase activity in human healthy and inflamed dental pulps.

    PubMed

    Spoto, G; Fioroni, M; Rubini, C; Tripodi, D; Perinetti, G; Piattelli, A

    2001-06-01

    Aspartate aminotransferase (AST) seems to be an important mediator of inflammatory processes. Its role in the progression and detection of inflammatory periodontal disease has been increasingly recognized in recent years. In the present study AST activity was analyzed in normal healthy human dental pulps, in reversible pulpitis, and in irreversible pulpitis. Enzymatic AST activity showed that the control values for the healthy pulps were 4.8 +/- 0.7 units/mg of pulp tissue. In reversible pulpitis specimens the AST activity increased to 7.98 +/- 2.1 units/mg of pulp tissue. In irreversible pulpitis specimens the values decreased to 2.28 +/- 1.7 units/mg of pulp tissue. Differences between the groups (control versus reversible pulpitis and reversible pulpitis versus irreversible pulpitis) were statistically significant (p = 0.0015). These results could point to a role of AST in the early events that lead to development of pulpal inflammation. PMID:11487132

  15. Stabilization and purification of tyrosine aminotransferase from rat liver.

    PubMed

    Hargrove, J L

    1990-01-01

    Purification of unmodified tyrosine aminotransferase from rat liver requires that the activity of cathepsin T be minimized, and that losses of enzyme due to dilution or oxidation by prevented. The enzyme was stabilized by pyridoxal 5'-phosphate, dithiothreitol, and potassium phosphate, but was destabilized by L-tyrosine or L-glutamate. A rapid, efficient method for purification of this enzyme included the following steps: twenty-fold induction with a high-casein diet plus dexamethasone phosphate administered in the drinking water; a heat step (65 degrees C) followed by precipitation from 0.20 M sucrose at pH 5.0; and small-scale chromatography on DEAE-cellulose, hydroxyapatite and CM-Sephadex C50 at pH 6.0. These steps yielded more than 10 mg of native enzyme from 35 rats, with a recovery of 68% of the initial activity. PMID:1973296

  16. Meta-analysis of the influence of TM6SF2 E167K variant on Plasma Concentration of Aminotransferases across different Populations and Diverse Liver Phenotypes

    PubMed Central

    Sookoian, Silvia; Pirola, Carlos J.

    2016-01-01

    A nonsynonymous E167K (rs58542926 C/T) variant in TM6SF2 gene was recently associated with nonalcoholic fatty liver disease (NAFLD). We explored the association between E167K and plasma concentrations of alanine (ALT) and aspartate (AST) aminotransferases through a meta-analysis. We also estimated the strength of the effect across diverse liver phenotypes, including NAFLD and chronic viral hepatitis; fourteen studies were included. We found that ALT (p = 3.2 × 10−6, n = 94,414) and AST (p = 0007, n = 93,809) levels were significantly associated with rs58542926 in NAFLD. By contrast, rs58542926 was not associated with either ALT (p = 0.24, n = 4187) or AST (p = 0.17, n = 2678) levels in four studies on chronic hepatitis. In conclusion, the results of the pooled estimates in patients with NAFLD showed that carriers of the T allele (EK + KK), when compared with homozygous subjects for the C allele (EE genotype) have increased levels of aminotransferases; however, this increase represents –2.5 (9.8%) and 1.2 (5%) IU/L of ALT and AST respectively, which is fairly small compared with the large effect of PNPLA3- rs738409-G allele that is associated with a –28% increase in serum ALT. PMID:27278285

  17. Meta-analysis of the influence of TM6SF2 E167K variant on Plasma Concentration of Aminotransferases across different Populations and Diverse Liver Phenotypes.

    PubMed

    Sookoian, Silvia; Pirola, Carlos J

    2016-01-01

    A nonsynonymous E167K (rs58542926 C/T) variant in TM6SF2 gene was recently associated with nonalcoholic fatty liver disease (NAFLD). We explored the association between E167K and plasma concentrations of alanine (ALT) and aspartate (AST) aminotransferases through a meta-analysis. We also estimated the strength of the effect across diverse liver phenotypes, including NAFLD and chronic viral hepatitis; fourteen studies were included. We found that ALT (p = 3.2 × 10(-6), n = 94,414) and AST (p = 0007, n = 93,809) levels were significantly associated with rs58542926 in NAFLD. By contrast, rs58542926 was not associated with either ALT (p = 0.24, n = 4187) or AST (p = 0.17, n = 2678) levels in four studies on chronic hepatitis. In conclusion, the results of the pooled estimates in patients with NAFLD showed that carriers of the T allele (EK + KK), when compared with homozygous subjects for the C allele (EE genotype) have increased levels of aminotransferases; however, this increase represents -2.5 (9.8%) and 1.2 (5%) IU/L of ALT and AST respectively, which is fairly small compared with the large effect of PNPLA3- rs738409-G allele that is associated with a -28% increase in serum ALT. PMID:27278285

  18. Metabolism of 7-ethyoxycoumarin by Isolated Perfused Rainbow Trout Livers

    EPA Science Inventory

    Isolated trout livers were perfused using methods designed to preserve tissue viability and function. Liver performance was evaluated by measuring O2 consumption, vascular resistance, K+ leakage, glucose flux, lactate flux, alanine aminotransferase leakage, and metabolic clearanc...

  19. Optimization of an Isolated Perfused Rainbow Trout Liver Model: Clearance Studies with 7-Ethoxycoumarin

    EPA Science Inventory

    Isolated trout livers were perfused using methods designed to preserve tissue viability and function. Liver performance was evaluated by measuring O2 consumption (VO2), vascular resistance, K+ leakage, glucose flux, lactate flux, alanine aminotransferase (ALT) leakage, and meta...

  20. Effect of arsenic and chromium on the serum amino-transferases activity in Indian major carp, Labeo rohita.

    PubMed

    Vutukuru, Sesha Srinivas; Prabhath, N Arun; Raghavender, M; Yerramilli, Anjaneyulu

    2007-09-01

    Arsenic and hexavalent chromium toxicity results from their ability to interact with sulfahydryl groups of proteins and enzymes, and to substitute phosphorus in a variety of biochemical reactions. Alanine aminotransferase (ALT; E.C: 2.6.1.2) and Aspartate amino transferase (AST; EC 2.6.1.1) play a crucial role in transamination reactions and can be used as potential biomarkers to indicate hepatotoxicity and cellular damage. While histopathological studies in liver tissue require more time and expertise, simple and reliable biochemical analysis of ALT and AST can be used for a rapid assessment of tissue and cellular damage within 96 h. The main objective of this study was to determine the acute effects of arsenic and hexavalent chromium on the activity of ALT and AST in the Indian major carp, Labeo rohita for 24 h and 96 h. Significant increase in the activity of ALT (P < 0.01) from controls in arsenic exposed fish indicates serious hepatic damage and distress condition to the fish. However, no such significant changes were observed in chromium-exposed fish suggesting that arsenic is more toxic to the fish. These findings indicate that ALT and AST are candidate biomarkers for arsenic-induced hepatotoxicity in Labeo rohita. PMID:17911661

  1. Effect of Arsenic and Chromium on the Serum Amino-Transferases Activity in Indian Major Carp, Labeo rohita

    PubMed Central

    Vutukuru, Sesha Srinivas; Arun Prabhath, N.; Raghavender, M.; Yerramilli, Anjaneyulu

    2007-01-01

    Arsenic and hexavalent chromium toxicity results from their ability to interact with sulfahydryl groups of proteins and enzymes, and to substitute phosphorus in a variety of biochemical reactions. Alanine aminotransferase (ALT; E.C: 2.6.1.2) and Aspartate amino transferase (AST; EC 2.6.1.1) play a crucial role in transamination reactions and can be used as potential biomarkers to indicate hepatotoxicity and cellular damage. While histopathological studies in liver tissue require more time and expertise, simple and reliable biochemical analysis of ALT and AST can be used for a rapid assessment of tissue and cellular damage within 96 h. The main objective of this study was to determine the acute effects of arsenic and hexavalent chromium on the activity of ALT and AST in the Indian major carp, Labeo rohita for 24 h and 96 h. Significant increase in the activity of ALT (P < 0.01) from controls in arsenic exposed fish indicates serious hepatic damage and distress condition to the fish. However, no such significant changes were observed in chromium-exposed fish suggesting that arsenic is more toxic to the fish. These findings indicate that ALT and AST are candidate biomarkers for arsenic-induced hepatotoxicity in Labeo rohita. PMID:17911661

  2. Crystallization and preliminary crystallographic analysis of d-alanine-d-alanine ligase from Streptococcus mutans

    SciTech Connect

    Lu, Yong-Zhi; Sheng, Yu; Li, Lan-Fen; Tang, De-Wei; Liu, Xiang-Yu; Zhao, Xiaojun; Liang, Yu-He Su, Xiao-Dong

    2007-09-01

    A potential target for antibiotic drug design, d-alanine-d-alanine ligase from S. mutans, was expressed in E. coli, purified and crystallized. Diffraction data were collected to 2.4 Å resolution. d-Alanine-d-alanine ligase is encoded by the gene ddl (SMU-599) in Streptococcus mutans. This ligase plays a very important role in cell-wall biosynthesis and may be a potential target for drug design. To study the structure and function of this ligase, the gene ddl was amplified from S. mutans genomic DNA and cloned into the expression vector pET28a. The protein was expressed in soluble form in Escherichia coli strain BL21 (DE3). Homogeneous protein was obtained using a two-step procedure consisting of Ni{sup 2+}-chelating and size-exclusion chromatography. Purified protein was crystallized and the cube-shaped crystal diffracted to 2.4 Å. The crystal belongs to space group P3{sub 1}21 or P3{sub 2}21, with unit-cell parameters a = b = 79.50, c = 108.97 Å. There is one molecule per asymmetric unit.

  3. Racemization of alanine by the alanine racemases from Salmonella typhimurium and Bacillus stearothermophilus: energetic reaction profiles

    SciTech Connect

    Faraci, W.S.; Walsh, C.T.

    1988-05-03

    Alanine racemases are bacterial pyridoxal 5'-phosphate (PLP) dependent enzymes providing D-alanine as an essential building block for biosynthesis of the peptidoglycan layer of the cell wall. Two isozymic alanine racemases, encoded by the dadB gene and the alr gene, from the Gram-negative mesophilic Salmonella typhimurium and one from the Gram-positive thermophilic Bacillus stearothermophilus have been examined for the racemization mechanism. Substrate deuterium isotope effects and solvent deuterium isotope effects have been measured in both L ..-->.. D and D..-->.. L directions for all three enzymes to assess the degree to which abstraction of the ..cap alpha..-proton or protonation of substrate PLP carbanion is limiting in catalysis. Additionally, experiments measuring internal return of ..cap alpha..-/sup 3/H from substrate to product and solvent exchange/substrate conversion experiments in /sup 3/H/sub 2/O have been used with each enzyme to examine the partitioning of substrate PLP carbanion intermediates and to obtain the relative heights of kinetically significant energy barriers in alanine racemase catalysis.

  4. Alteration of substrate specificity of alanine dehydrogenase

    PubMed Central

    Fernandes, Puja; Aldeborgh, Hannah; Carlucci, Lauren; Walsh, Lauren; Wasserman, Jordan; Zhou, Edward; Lefurgy, Scott T.; Mundorff, Emily C.

    2015-01-01

    The l-alanine dehydrogenase (AlaDH) has a natural history that suggests it would not be a promising candidate for expansion of substrate specificity by protein engineering: it is the only amino acid dehydrogenase in its fold family, it has no sequence or structural similarity to any known amino acid dehydrogenase, and it has a strong preference for l-alanine over all other substrates. By contrast, engineering of the amino acid dehydrogenase superfamily members has produced catalysts with expanded substrate specificity; yet, this enzyme family already contains members that accept a broad range of substrates. To test whether the natural history of an enzyme is a predictor of its innate evolvability, directed evolution was carried out on AlaDH. A single mutation identified through molecular modeling, F94S, introduced into the AlaDH from Mycobacterium tuberculosis (MtAlaDH) completely alters its substrate specificity pattern, enabling activity toward a range of larger amino acids. Saturation mutagenesis libraries in this mutant background additionally identified a double mutant (F94S/Y117L) showing improved activity toward hydrophobic amino acids. The catalytic efficiencies achieved in AlaDH are comparable with those that resulted from similar efforts in the amino acid dehydrogenase superfamily and demonstrate the evolvability of MtAlaDH specificity toward other amino acid substrates. PMID:25538307

  5. Hormonal contraception and lactation.

    PubMed

    Kelsey, J J

    1996-12-01

    Hormonal contraceptive measures can be used immediately postpartum if the patient so desires. Progestin-only contraceptives are preferable to estrogen-containing methods if initiated during the first six months after delivery. Progestin only contraceptives do not appear to affect milk volume, composition, or to cause deleterious effects in the infant. Ideally for women who desire a form of contraception in addition to lactation-induced amenorrhea, progestin-only methods should be started at six weeks postpartum if the woman is fully breastfeeding. Since contraception protection is provided by lactation amenorrhea, the six week delay will decrease infant exposure to exogenous hormones and decrease the incidence of irregular postpartum bleeding. Milk volume may decrease with the use of estrogen; however, no detrimental effects have been shown on infant growth or development. For women who are planning to gradually wean their infant, use of COCs may provide an easier transition to bottle-feeding. COCs should be used with caution by women who are not able to obtain supplemental milk. A decrease in milk volume can lead to earlier discontinuation of the hormonal contraceptive in an attempt to increase milk quantity. Supplementation is often needed, and then the woman ovulates again, possibly resulting in an unintended pregnancy. Many women are motivated immediately postpartum to accept contraception. For other women, lack of access to health care may provide barriers in obtaining adequate contraception later. In either case, there are adequate data to show no detriments of starting progestin-only contraceptives within days of delivery. Therefore, the best method for the patient should be employed to ensure adequate contraception while preserving optimal lactation. PMID:9025449

  6. A study of L-leucine, L-phenylalanine and L-alanine transport in the perfused rat mammary gland: possible involvement of LAT1 and LAT2.

    PubMed

    Shennan, D B; Calvert, D T; Travers, M T; Kudo, Y; Boyd, C A R

    2002-08-19

    The transport of L-leucine, L-phenylalanine and L-alanine by the perfused lactating rat mammary gland has been examined using a rapid, paired-tracer dilution technique. The clearances of all three amino acids by the mammary gland consisted of a rising phase followed by a rapid fall-off, respectively, reflecting influx and efflux of the radiotracers. The peak clearance of L-leucine was inhibited by BCH (65%) and D-leucine (58%) but not by L-proline. The inhibition of L-leucine clearance by BCH and D-leucine was not additive. L-leucine inhibited the peak clearance of radiolabelled L-leucine by 78%. BCH also inhibited the peak clearance of L-phenylalanine (66%) and L-alanine (33%) by the perfused mammary gland. Lactating rat mammary tissue was found to express both LAT1 and LAT2 mRNA. The results suggest that system L is situated in the basolateral aspect of the lactating rat mammary epithelium and thus probably plays a central role in neutral amino acid uptake from blood. The finding that L-alanine uptake by the gland was inhibited by BCH suggests that LAT2 may make a significant contribution to neutral amino acid uptake by the mammary epithelium. PMID:12101005

  7. International society of sports nutrition position stand: Beta-Alanine.

    PubMed

    Trexler, Eric T; Smith-Ryan, Abbie E; Stout, Jeffrey R; Hoffman, Jay R; Wilborn, Colin D; Sale, Craig; Kreider, Richard B; Jäger, Ralf; Earnest, Conrad P; Bannock, Laurent; Campbell, Bill; Kalman, Douglas; Ziegenfuss, Tim N; Antonio, Jose

    2015-01-01

    The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4-6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4-6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine. PMID:26175657

  8. Radiochemical microassay for aspartate aminotransferase activity in the nervous system

    SciTech Connect

    Garrison, D.; Beattie, J.; Namboodiri, M.A.

    1988-07-01

    A radiochemical procedure for measuring aspartate aminotransferase activity in the nervous system is described. The method is based on the exchange of tritium atoms at positions 2 and 3 of L-2,3-(/sup 3/H)aspartate with water when this amino acid is transaminated in the presence of alpha-ketoglutarate to form oxaloacetate. The tritiated water is separated from the radiolabeled aspartate by passing the reaction mixture over a cation exchange column. Confirmation that the radioactivity in the product is associated with water was obtained by separating it by anion exchange HPLC and by evaporation. The product formation is linear with time up to 120 min and with tissue in the 0.05- to 10-micrograms range. The apparent Km for aspartate in the rat brain homogenate is found to be 0.83 mM and that for alpha-ketoglutarate to be 0.12 mM. Methods that further improve the sensitivity of the assay are also discussed.

  9. Tyrosine aminotransferase from Leishmania infantum: A new drug target candidate.

    PubMed

    Moreno, Miguel Angel; Alonso, Ana; Alcolea, Pedro Jose; Abramov, Ariel; de Lacoba, Mario García; Abendroth, Jan; Zhang, Sunny; Edwards, Thomas; Lorimer, Don; Myler, Peter John; Larraga, Vicente

    2014-12-01

    Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis in the Mediterranean basin. The disease is fatal without treatment, which has been based on antimonial pentavalents for more than 60 years. Due to resistances, relapses and toxicity to current treatment, the development of new drugs is required. The structure of the L. infantum tyrosine aminotransferase (LiTAT) has been recently solved showing important differences with the mammalian orthologue. The characterization of LiTAT is reported herein. This enzyme is cytoplasmic and is over-expressed in the more infective stages and nitric oxide resistant parasites. Unlike the mammalian TAT, LiTAT is able to use ketomethiobutyrate as co-substrate. The pharmacophore model of LiTAT with this specific co-substrate is described herein. This may allow the identification of new inhibitors present in the databases. All the data obtained support that LiTAT is a good target candidate for the development of new anti-leishmanial drugs. PMID:25516846

  10. Tyrosine aminotransferase from Leishmania infantum: A new drug target candidate

    PubMed Central

    Moreno, Miguel Angel; Alonso, Ana; Alcolea, Pedro Jose; Abramov, Ariel; de Lacoba, Mario García; Abendroth, Jan; Zhang, Sunny; Edwards, Thomas; Lorimer, Don; Myler, Peter John; Larraga, Vicente

    2014-01-01

    Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis in the Mediterranean basin. The disease is fatal without treatment, which has been based on antimonial pentavalents for more than 60 years. Due to resistances, relapses and toxicity to current treatment, the development of new drugs is required. The structure of the L. infantum tyrosine aminotransferase (LiTAT) has been recently solved showing important differences with the mammalian orthologue. The characterization of LiTAT is reported herein. This enzyme is cytoplasmic and is over-expressed in the more infective stages and nitric oxide resistant parasites. Unlike the mammalian TAT, LiTAT is able to use ketomethiobutyrate as co-substrate. The pharmacophore model of LiTAT with this specific co-substrate is described herein. This may allow the identification of new inhibitors present in the databases. All the data obtained support that LiTAT is a good target candidate for the development of new anti-leishmanial drugs. PMID:25516846

  11. Expression of the soybean (Glycine max) glutamate 1-semialdehyde aminotransferase gene in symbiotic root nodules.

    PubMed

    Sangwan, I; O'Brian, M R

    1993-07-01

    Extracts of soybean (Glycine max) root nodules and greening etiolated leaves catalyzed radiolabeled delta-aminolevulinic acid (ALA) formation from 3,4-[3H]glutamate but not from 1-[14C]glutamate. Nevertheless, those tissue extracts expressed the activity of glutamate 1-semialdehyde (GSA) aminotransferase, the C5 pathway enzyme that catalyzes ALA synthesis from GSA for tetrapyrrole formation. A soybean nodule cDNA clone that conferred ALA prototrophy, GSA aminotransferase activity, and glutamate-dependent ALA formation activity on an Escherichia coli GSA aminotransferase mutant was isolated. The deduced product of the nodule cDNA shared 79% identity with the GSA aminotransferase expressed in barley leaves, providing, along with the complementation data, strong evidence that the cDNA encodes GSA aminotransferase. GSA aminotransferase mRNA and enzyme activity were expressed in nodules but not in uninfected roots, indicating that the Gsa gene is induced in the symbiotic tissue. The Gsa gene was strongly expressed in leaves of etiolated plantlets independently of light treatment and, to a much lesser extent, in leaves of mature plants. We conclude that GSA aminotransferase, and possibly the C5 pathway, is expressed in a nonphotosynthetic plant organ for nodule heme synthesis and that Gsa is a regulated gene in soybean. PMID:8278535

  12. Sensitive non-radioactive determination of aminotransferase stereospecificity for C-4' hydrogen transfer on the coenzyme

    SciTech Connect

    Jomrit, Juntratip; Summpunn, Pijug; Meevootisom, Vithaya; Wiyakrutta, Suthep

    2011-02-25

    Research highlights: {yields} Stereochemical mechanism of PLP enzymes is important but difficult to determine. {yields} This new method is significantly less complicated than the previous ones. {yields} This assay is as sensitive as the radioactive based method. {yields} LC-MS/MS positively identify the analyte coenzyme. {yields} The method can be used with enzyme whose apo form is unstable. -- Abstract: A sensitive non-radioactive method for determination of the stereospecificity of the C-4' hydrogen transfer on the coenzymes (pyridoxal phosphate, PLP; and pyridoxamine phosphate, PMP) of aminotransferases has been developed. Aminotransferase of unknown stereospecificity in its PLP form was incubated in {sup 2}H{sub 2}O with a substrate amino acid resulted in PMP labeled with deuterium at C-4' in the pro-S or pro-R configuration according to the stereospecificity of the aminotransferase tested. The [4'-{sup 2}H]PMP was isolated from the enzyme protein and divided into two portions. The first portion was incubated in aqueous buffer with apo-aspartate aminotransferase (a reference si-face specific enzyme), and the other was incubated with apo-branched-chain amino acid aminotransferase (a reference re-face specific enzyme) in the presence of a substrate 2-oxo acid. The {sup 2}H at C-4' is retained with the PLP if the aminotransferase in question transfers C-4' hydrogen on the opposite face of the coenzyme compared with the reference aminotransferase, but the {sup 2}H is removed if the test and reference aminotransferases catalyze hydrogen transfer on the same face. PLP formed in the final reactions was analyzed by LC-MS/MS for the presence or absence of {sup 2}H. The method was highly sensitive that for the aminotransferase with ca. 50 kDa subunit molecular weight, only 2 mg of the enzyme was sufficient for the whole test. With this method, the use of radioactive substances could be avoided without compromising the sensitivity of the assay.

  13. Biochemical and Structural Properties of Mouse Kynurenine Aminotransferase III

    SciTech Connect

    Han, Q.; Robinson, H; Cai, T; Tagle, D; Li, J

    2009-01-01

    Kynurenine aminotransferase III (KAT III) has been considered to be involved in the production of mammalian brain kynurenic acid (KYNA), which plays an important role in protecting neurons from overstimulation by excitatory neurotransmitters. The enzyme was identified based on its high sequence identity with mammalian KAT I, but its activity toward kynurenine and its structural characteristics have not been established. In this study, the biochemical and structural properties of mouse KAT III (mKAT III) were determined. Specifically, mKAT III cDNA was amplified from a mouse brain cDNA library, and its recombinant protein was expressed in an insect cell protein expression system. We established that mKAT III is able to efficiently catalyze the transamination of kynurenine to KYNA and has optimum activity at relatively basic conditions of around pH 9.0 and at relatively high temperatures of 50 to 60C. In addition, mKAT III is active toward a number of other amino acids. Its activity toward kynurenine is significantly decreased in the presence of methionine, histidine, glutamine, leucine, cysteine, and 3-hydroxykynurenine. Through macromolecular crystallography, we determined the mKAT III crystal structure and its structures in complex with kynurenine and glutamine. Structural analysis revealed the overall architecture of mKAT III and its cofactor binding site and active center residues. This is the first report concerning the biochemical characteristics and crystal structures of KAT III enzymes and provides a basis toward understanding the overall physiological role of mammalian KAT III in vivo and insight into regulating the levels of endogenous KYNA through modulation of the enzyme in the mouse brain.

  14. Tyrosine Aminotransferase: Biochemical and Structural Properties and Molecular Dynamics Simulations

    SciTech Connect

    P Mehere; Q Han; J Lemkul; C Vavricka; H Robinson; D Bevan; J Li

    2011-12-31

    Tyrosine aminotransferase (TAT) catalyzes the transamination of tyrosine and other aromatic amino acids. The enzyme is thought to play a role in tyrosinemia type II, hepatitis and hepatic carcinoma recovery. The objective of this study is to investigate its biochemical and structural characteristics and substrate specificity in order to provide insight regarding its involvement in these diseases. Mouse TAT (mTAT) was cloned from a mouse cDNA library, and its recombinant protein was produced using Escherichia coli cells and purified using various chromatographic techniques. The recombinant mTAT is able to catalyze the transamination of tyrosine using {alpha}-ketoglutaric acid as an amino group acceptor at neutral pH. The enzyme also can use glutamate and phenylalanine as amino group donors and p-hydroxy-phenylpyruvate, phenylpyruvate and alpha-ketocaproic acid as amino group acceptors. Through macromolecular crystallography we have determined the mTAT crystal structure at 2.9 {angstrom} resolution. The crystal structure revealed the interaction between the pyridoxal-5'-phosphate cofactor and the enzyme, as well as the formation of a disulphide bond. The detection of disulphide bond provides some rational explanation regarding previously observed TAT inactivation under oxidative conditions and reactivation of the inactive TAT in the presence of a reducing agent. Molecular dynamics simulations using the crystal structures of Trypanosoma cruzi TAT and human TAT provided further insight regarding the substrate-enzyme interactions and substrate specificity. The biochemical and structural properties of TAT and the binding of its cofactor and the substrate may help in elucidation of the mechanism of TAT inhibition and activation.

  15. Tyrosine aminotransferase: biochemical and structural properties and molecular dynamics simulations

    SciTech Connect

    Mehere, P.; Robinson, H.; Han, Q.; Lemkul, J. A.; Vavricka, C. J.; Bevan, D. R.; Li, J.

    2010-11-01

    Tyrosine aminotransferase (TAT) catalyzes the transamination of tyrosine and other aromatic amino acids. The enzyme is thought to play a role in tyrosinemia type II, hepatitis and hepatic carcinoma recovery. The objective of this study is to investigate its biochemical and structural characteristics and substrate specificity in order to provide insight regarding its involvement in these diseases. Mouse TAT (mTAT) was cloned from a mouse cDNA library, and its recombinant protein was produced using Escherichia coli cells and purified using various chromatographic techniques. The recombinant mTAT is able to catalyze the transamination of tyrosine using {alpha}-ketoglutaric acid as an amino group acceptor at neutral pH. The enzyme also can use glutamate and phenylalanine as amino group donors and p-hydroxy-phenylpyruvate, phenylpyruvate and alpha-ketocaproic acid as amino group acceptors. Through macromolecular crystallography we have determined the mTAT crystal structure at 2.9 {angstrom} resolution. The crystal structure revealed the interaction between the pyridoxal-5'-phosphate cofactor and the enzyme, as well as the formation of a disulphide bond. The detection of disulphide bond provides some rational explanation regarding previously observed TAT inactivation under oxidative conditions and reactivation of the inactive TAT in the presence of a reducing agent. Molecular dynamics simulations using the crystal structures of Trypanosoma cruzi TAT and human TAT provided further insight regarding the substrate-enzyme interactions and substrate specificity. The biochemical and structural properties of TAT and the binding of its cofactor and the substrate may help in elucidation of the mechanism of TAT inhibition and activation.

  16. Two alanine aminotranferases link mitochondrial glycolate oxidation to the major photorespiratory pathway in Arabidopsis and rice.

    PubMed

    Niessen, Markus; Krause, Katrin; Horst, Ina; Staebler, Norma; Klaus, Stephanie; Gaertner, Stefanie; Kebeish, Rashad; Araujo, Wagner L; Fernie, Alisdair R; Peterhansel, Christoph

    2012-04-01

    The major photorespiratory pathway in higher plants is distributed over chloroplasts, mitochondria, and peroxisomes. In this pathway, glycolate oxidation takes place in peroxisomes. It was previously suggested that a mitochondrial glycolate dehydrogenase (GlcDH) that was conserved from green algae lacking leaf-type peroxisomes contributes to photorespiration in Arabidopsis thaliana. Here, the identification of two Arabidopsis mitochondrial alanine:glyoxylate aminotransferases (ALAATs) that link glycolate oxidation to glycine formation are described. By this reaction, the mitochondrial side pathway produces glycine from glyoxylate that can be used in the glycine decarboxylase (GCD) reaction of the major pathway. RNA interference (RNAi) suppression of mitochondrial ALAAT did not result in major changes in metabolite pools under standard conditions or enhanced photorespiratroy flux, respectively. However, RNAi lines showed reduced photorespiratory CO(2) release and a lower CO(2) compensation point. Mitochondria isolated from RNAi lines are incapable of converting glycolate to CO(2), whereas simultaneous overexpression of GlcDH and ALAATs in transiently transformed tobacco leaves enhances glycolate conversion. Furthermore, analyses of rice mitochondria suggest that the side pathway for glycolate oxidation and glycine formation is conserved in monocotyledoneous plants. It is concluded that the photorespiratory pathway from green algae has been functionally conserved in higher plants. PMID:22268146

  17. Kinetics of steroid induction and deinduction of tyrosine aminotransferase synthesis in cultured hepatoma cells.

    PubMed Central

    Steinberg, R A; Levinson, B B; Tomkins, G M

    1975-01-01

    The specific rate of synthesis of tyrosine aminotransferase (EC 2.6.1.5; L-tyrosine:2-oxoglutarate aminotransferase) is used as a measure of the level of functional, cytoplasmic, tyrosine aminotransferase-specific mRNA in cultured rat hepatoma cells. An analysis of the kinetics of change in this rate after the addition or withdrawal of glucocorticosteroids sets an upper limit on the half-life of the enzyme-specific mRNA of 1-1.5 hr, whether or not steroid is present. The inactivation rate of the enzyme mRNA is independent of the growth condition of the cells, occuring equally rapidly in the presence or absence of serum or insulin, both of which induce tyrosine aminotransferase in these cells. The implications of these results for the mechanism of steroid induction are discussed. PMID:237268

  18. Comparison of EPR response of alanine and Gd₂O₃-alanine dosimeters exposed to TRIGA Mainz reactor.

    PubMed

    Marrale, M; Schmitz, T; Gallo, S; Hampel, G; Longo, A; Panzeca, S; Tranchina, L

    2015-12-01

    In this work we report some preliminary results regarding the analysis of electron paramagnetic resonance (EPR) response of alanine pellets and alanine pellets added with gadolinium used for dosimetry at the TRIGA research reactor in Mainz, Germany. Two set-ups were evaluated: irradiation inside PMMA phantom and irradiation inside boric acid phantom. We observed that the presence of Gd2O3 inside alanine pellets increases the EPR signal by a factor of 3.45 and 1.24 in case of PMMA and boric acid phantoms, respectively. We can conclude that in the case of neutron beam with a predominant thermal neutron component the addition of gadolinium oxide can significantly improve neutron sensitivity of alanine pellets. Monte Carlo (MC) simulations of both response of alanine and Gd-added alanine pellets with FLUKA code were performed and a good agreement was achieved for pure alanine dosimeters. For Gd2O3-alanine deviations between MC simulations and experimental data were observed and discussed. PMID:26315099

  19. Three-dimensional structure of a pyridoxal-phosphate-dependent enzyme, mitochondrial aspartate aminotransferase.

    PubMed Central

    Ford, G C; Eichele, G; Jansonius, J N

    1980-01-01

    X-ray diffraction studies to 2.8-A resolution have yielded the three-dimensional structure of mitochondrial aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1), an isologous alpha 2 dimer (Mr = 2 x 45,000). The subunits are rich in secondary structure and contain two domains, one of which anchors the coenzyme, pyridoxal 5'-phosphate. Each active site lies between the subunits and is composed of residues from both of them. PMID:6930651

  20. Lactate and lactate clearance in acute cardiac care patients

    PubMed Central

    Lazzeri, Chiara; Picariello, Claudio; Dini, Carlotta Sorini; Gensini, Gian Franco; Valente, Serafina

    2012-01-01

    Hyperlactataemia is commonly used as a diagnostic and prognostic tool in intensive care settings. Recent studies documented that serial lactate measurements over time (or lactate clearance), may be clinically more reliable than lactate absolute value for risk stratification in different pathological conditions. While the negative prognostic role of hyperlactataemia in several critical ill diseases (such as sepsis and trauma) is well established, data in patients with acute cardiac conditions (i.e. acute coronary syndromes) are scarce and controversial. The present paper provides an overview of the current available evidence on the clinical role of lactic acid levels and lactate clearance in acute cardiac settings (acute coronary syndromes, cardiogenic shock, cardiac surgery), focusing on its prognostic role. PMID:24062898

  1. Migraine in pregnancy and lactation.

    PubMed

    David, Paru S; Kling, Juliana M; Starling, Amaal J

    2014-04-01

    Migraine headache is a significant health problem affecting women more than men. In women, the hormonal fluctuations seen during pregnancy and lactation can affect migraine frequency and magnitude. Understanding the evaluation of headache in pregnancy is important, especially given the increased risk of secondary headache conditions. Pregnancy and lactation can complicate treatment options for women with migraine because of the risk of certain medications to the fetus. This review includes details of the workup and then provides treatment options for migraine during pregnancy and lactation. PMID:24604057

  2. Optimal cut-off value of alanine aminotransferase level to precisely estimate the presence of fatty liver in patients with poorly controlled type 2 diabetes.

    PubMed

    Tanabe, Akihito; Tatsumi, Fuminori; Okauchi, Seizo; Yabe, Hiroki; Tsuda, Tomohiro; Okutani, Kazuma; Yamashita, Kazuki; Nakashima, Koji; Kaku, Kohei; Kaneto, Hideaki

    2016-07-01

    Optimal cut-off value of ALT level to precisely estimate the presence of fatty liver was as low as 28.0 U/L. We should consider the possibility of fatty liver even when ALT level is within normal range in subjects with poorly controlled type 2 diabetes. PMID:27373695

  3. Aspartate Aminotransferase in Alfalfa Root Nodules : III. Genotypic and Tissue Expression of Aspartate Aminotransferase in Alfalfa and Other Species.

    PubMed

    Farnham, M W; Griffith, S M; Miller, S S; Vance, C P

    1990-12-01

    Aspartate aminotransferase (AAT) plays an important role in nitrogen metabolism in all plants and is particularly important in the assimilation of fixed N derived from the legume-Rhizoblum symbiosis. Two isozymes of AAT (AAT-1 and AAT-2) occur in alfalfa (Medicago sativa L.). Antibodies against alfalfa nodule AAT-2 do not recognize AAT-1, and these antibodies were used to study AAT-2 expression in different tissues and genotypes of alfalfa and also in other legume and nonlegume species. Rocket immunoelectrophoresis indicated that nodules of 38-day-old alfalfa plants contained about eight times more AAT-2 than did nodules of 7-day-old plants, confirming the nodule-enhanced nature of this isozyme. AAT-2 was estimated to make up 16, 15, 5, and 8 milligrams per gram of total soluble protein in mature nodules, roots, stems, and leaves, respectively, of effective N(2)-fixing alfalfa. The concentration of AAT-2 in nodules of ineffective non-N(2)-fixing alafalfa genotypes was about 70% less than that of effective nodules. Western blots of soluble protein from nodules of nine legume species indicated that a 40-kilodalton polypeptide that reacts strongly with AAT-2 antibodies is conserved in legumes. Nodule AAT-2 immunoprecipitation data suggested that amide- and ureide-type legumes may differ in expression and regulation of the enzyme. In addition, Western blotting and immunoprecipitations of AAT activity demonstrated that antibodies against alfalfa AAT-2 are highly cross-reactive with AAT enzyme protein in leaves of soybean (Glycine max L.), wheat (Triticum aestivum L.), and maize (Zea mays L.) and in roots of maize, but not with AAT in soybean and wheat roots. Results from this study indicate that AAT-2 is structurally conserved and localized in similar tissues among diverse species. PMID:16667896

  4. The Structure of NtdA, a Sugar Aminotransferase Involved in the Kanosamine Biosynthetic Pathway in Bacillus subtilis, Reveals a New Subclass of Aminotransferases*

    PubMed Central

    van Straaten, Karin E.; Ko, Jong Bum; Jagdhane, Rajendra; Anjum, Shazia; Palmer, David R. J.; Sanders, David A. R.

    2013-01-01

    NtdA from Bacillus subtilis is a sugar aminotransferase that catalyzes the pyridoxal phosphate-dependent equatorial transamination of 3-oxo-α-d-glucose 6-phosphate to form α-d-kanosamine 6-phosphate. The crystal structure of NtdA shows that NtdA shares the common aspartate aminotransferase fold (Type 1) with residues from both monomers forming the active site. The crystal structures of NtdA alone, co-crystallized with the product α-d-kanosamine 6-phosphate, and incubated with the amine donor glutamate reveal three key structures in the mechanistic pathway of NtdA. The structure of NtdA alone reveals the internal aldimine form of NtdA with the cofactor pyridoxal phosphate covalently attached to Lys-247. The addition of glutamate results in formation of pyridoxamine phosphate. Co-crystallization with kanosamine 6-phosphate results in the formation of the external aldimine. Only α-d-kanosamine 6-phosphate is observed in the active site of NtdA, not the β-anomer. A comparison of the structure and sequence of NtdA with other sugar aminotransferases enables us to propose that the VIβ family of aminotransferases should be divided into subfamilies based on the catalytic lysine motif. PMID:24097983

  5. Lactate dehydrogenase-elevating virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter describes the taxonomic classification of Lactate dehydrogenase-elevating virus (LDV). Included are: host, genome, classification, morphology, physicochemical and physical properties, nucleic acid, proteins, lipids, carbohydrates, geographic range, phylogenetic properties, biologic...

  6. Lactate levels with glioblastoma multiforme.

    PubMed

    Kahlon, Arunpreet Singh; Alexander, Mariam; Kahlon, Arundeep; Wright, Jonathan

    2016-07-01

    A 37-year-old woman with known glioblastoma multiforme was admitted for treatment of new deep vein thrombosis. Anion gap and plasma lactate levels were found to be elevated. Magnetic resonance imaging of the brain showed a stable, advanced glioblastoma multiforme. All causes of lactic acidosis, including infections and medications, were ruled out. Aggressive tumors have been shown to produce lactate levels in minute quantities in their microenvironment, which helps them metastasize and evade immune response and even radiation. PMID:27365883

  7. Lactate levels with glioblastoma multiforme

    PubMed Central

    Kahlon, Arunpreet Singh; Alexander, Mariam; Kahlon, Arundeep

    2016-01-01

    A 37-year-old woman with known glioblastoma multiforme was admitted for treatment of new deep vein thrombosis. Anion gap and plasma lactate levels were found to be elevated. Magnetic resonance imaging of the brain showed a stable, advanced glioblastoma multiforme. All causes of lactic acidosis, including infections and medications, were ruled out. Aggressive tumors have been shown to produce lactate levels in minute quantities in their microenvironment, which helps them metastasize and evade immune response and even radiation. PMID:27365883

  8. Lactating Adenoma of the Breast.

    PubMed

    Barco Nebreda, Israel; Vidal, M Carmen; Fraile, Manel; Canales, Lydia; González, Clarisa; Giménez, Nuria; García-Fernández, Antonio

    2016-08-01

    Lactating adenoma is an uncommon breast palpable lesion occurring in pregnancy or lactation. Although it is a benign condition, it often requires core biopsy or even surgery to exclude malignancy. As with other solid lesions in pregnancy and lactation, lactating adenoma needs an accurate evaluation in order to ensure its benign nature. Work-up must include both imaging and histologic findings. Ultrasound evaluation remains the first step in assessing the features of the lesion. Some authors consider magnetic resonance imaging as a useful tool in cases of inconclusive evaluation after ultrasound and histologic exam in an attempt to avoid surgery. Most lactating adenomas resolve spontaneously, whereas others persist or even increase in size and must be removed. The authors present a case of a 35-year-old woman at 6 months postpartum with a lactating adenoma in her right breast. After surgical removal, breastfeeding was perfectly continued within the next 24 hours, which highlights the fact that breast surgery is most often compatible with breastfeeding. PMID:27197575

  9. REVERSAL OF d-CYCLOSERINE INHIBITION OF BACTERIAL GROWTH BY ALANINE

    PubMed Central

    Zygmunt, Walter A.

    1962-01-01

    Zygmunt, Walter A. (Mead Johnson & Co., Evansville, Ind.). Reversal of d-cycloserine inhibition of bacterial growth by alanine. J. Bacteriol. 84:154–156. 1962.—Reversal of the antibacterial activity of d-4-amino-3-isoxazolidone by alanine in bacterial cultures actively growing on chemically defined media was compared in cultures requiring exogenous alanine and those capable of its synthesis. dl-Alanine was the most effective reversal agent in Pediococcus cerevisiae, an alanine-requiring organism, and d-alanine was effective in Escherichia coli and Staphylococcus aureus, organisms synthesizing alanine. With all three cultures, l-alanine was the least effective reversal agent. PMID:16561951

  10. Metabolomics Analysis Identifies D-Alanine-D-alanine Ligase as the Primary Lethal Target of D-cycloserine in Mycobacteria

    PubMed Central

    Halouska, Steven; Fenton, Robert J.; Zinniel, Denise K.; Marshall, Darrell D.; Barletta, Raúl G.; Powers, Robert

    2014-01-01

    D-cycloserine is an effective second line antibiotic used as a last resort to treat multi (MDR)- and extensively (XDR)- drug resistant strains of Mycobacterium tuberculosis. D-cycloserine interferes with the formation of peptidoglycan biosynthesis by competitive inhibition of Alanine racemase (Alr) and D-Alanine-D-alanine ligase (Ddl). Although, the two enzymes are known to be inhibited, the in vivo lethal target is still unknown. Our NMR metabolomics work has revealed that Ddl is the primary target of DCS, as cell growth is inhibited when the production of D-alanyl-D-alanine is halted. It is shown that inhibition of Alr may contribute indirectly by lowering the levels of D-alanine thus allowing DCS to outcompete D-alanine for Ddl binding. The NMR data also supports the possibility of a transamination reaction to produce D-alanine from pyruvate and glutamate, thereby bypassing Alr inhibition. Furthermore, the inhibition of peptidoglycan synthesis results in a cascading effect on cellular metabolism as there is a shift toward the catabolic routes to compensate for accumulation of peptidoglycan precursors. PMID:24303782

  11. Postirradiation effects in alanine dosimeter probes of two different suppliers.

    PubMed

    Anton, Mathias

    2008-03-01

    The measurand relevant for the dosimetry for radiation therapy is the absorbed dose to water, DW. The Physikalisch-Technische Bundesanstalt (PTB) is establishing a secondary standard for DW for high-energy photon and electron radiation based on electron spin resonance (ESR) of the amino acid alanine. For practical applications, like, for example, intercomparison measurements using the ESR/alanine dosimetry system, the temporal evolution of the ESR signal of irradiated probes is an important issue. This postirradiation behaviour is investigated for alanine pellets of two different suppliers for different storage conditions. The influence of the storage conditions on the temporal evolution may be dependent on the type of probes used. The measurement and analysis method developed at the PTB is able to circumvent the apparent difficulties in the case of alanine/paraffin probes. Care has to be taken in case this method cannot be applied. PMID:18296760

  12. Relationship Between Hepatic Steatosis and the Elevation of Aminotransferases in HBV-Infected Patients With HBe-Antigen Negativity and a Low Viral Load.

    PubMed

    Enomoto, Hirayuki; Aizawa, Nobuhiro; Nishikawa, Hiroki; Ikeda, Naoto; Sakai, Yoshiyuki; Takata, Ryo; Hasegawa, Kunihiro; Nakano, Chikage; Nishimura, Takashi; Yoh, Kazunori; Ishii, Akio; Takashima, Tomoyuki; Iwata, Yoshinori; Iijima, Hiroko; Nishiguchi, Shuhei

    2016-04-01

    Nonalcoholic fatty liver disease has been suggested to be associated with alanine aminotransferase (ALT) elevation in hepatitis B virus (HBV)-infected patients with HBe antigen (HBeAg)-negativity and a low HBV-DNA level. However, few studies have evaluated the association according to histological findings of the liver.Among a total of 198 HBV-infected patients who received a percutaneous liver biopsy, we studied the histological and laboratory findings of HBeAg-negative patients without receiving nucleoside/nucleotide analogues treatment (N = 70) in order to evaluate whether hepatic steatosis and its related metabolic disorders were associated with an elevation in ALT levels in HBeAg-negative patients.In HBeAg-negative patients with a high serum HBV-DNA level (≥2000 IU/mL), the level of HBV-DNA was the only significant factor related to ALT elevation. However, in HBeAg-negative patients with a low HBV-DNA level, the serum ferritin level, and histologically observed hepatic steatosis were significantly associated factors with ALT elevation. When we evaluated 2 metabolic variables (serum ferritin and fasting insulin) that are suggested to be relevant to the presence of progressive disease in Japanese patients, we found that the rate of metabolic disorders was significantly higher among patients with a high ALT level and a low HBV-DNA level than it was among those with other conditions. The triglyceride level and the frequency of moderate or severe hepatic steatosis were significantly higher in patients with a low HBV-DNA level than in those with a high HBV-DNA level.Histologically proven hepatic steatosis and its related metabolic disorders are suggested to be involved in the elevation of aminotransferases of HBeAg-negative patients, particularly those with low HBV-DNA levels. PMID:27124068

  13. Relationship Between Hepatic Steatosis and the Elevation of Aminotransferases in HBV-Infected Patients With HBe-Antigen Negativity and a Low Viral Load

    PubMed Central

    Enomoto, Hirayuki; Aizawa, Nobuhiro; Nishikawa, Hiroki; Ikeda, Naoto; Sakai, Yoshiyuki; Takata, Ryo; Hasegawa, Kunihiro; Nakano, Chikage; Nishimura, Takashi; Yoh, Kazunori; Ishii, Akio; Takashima, Tomoyuki; Iwata, Yoshinori; Iijima, Hiroko; Nishiguchi, Shuhei

    2016-01-01

    Abstract Nonalcoholic fatty liver disease has been suggested to be associated with alanine aminotransferase (ALT) elevation in hepatitis B virus (HBV)-infected patients with HBe antigen (HBeAg)-negativity and a low HBV-DNA level. However, few studies have evaluated the association according to histological findings of the liver. Among a total of 198 HBV-infected patients who received a percutaneous liver biopsy, we studied the histological and laboratory findings of HBeAg-negative patients without receiving nucleoside/nucleotide analogues treatment (N = 70) in order to evaluate whether hepatic steatosis and its related metabolic disorders were associated with an elevation in ALT levels in HBeAg-negative patients. In HBeAg-negative patients with a high serum HBV-DNA level (≥2000 IU/mL), the level of HBV-DNA was the only significant factor related to ALT elevation. However, in HBeAg-negative patients with a low HBV-DNA level, the serum ferritin level, and histologically observed hepatic steatosis were significantly associated factors with ALT elevation. When we evaluated 2 metabolic variables (serum ferritin and fasting insulin) that are suggested to be relevant to the presence of progressive disease in Japanese patients, we found that the rate of metabolic disorders was significantly higher among patients with a high ALT level and a low HBV-DNA level than it was among those with other conditions. The triglyceride level and the frequency of moderate or severe hepatic steatosis were significantly higher in patients with a low HBV-DNA level than in those with a high HBV-DNA level. Histologically proven hepatic steatosis and its related metabolic disorders are suggested to be involved in the elevation of aminotransferases of HBeAg-negative patients, particularly those with low HBV-DNA levels. PMID:27124068

  14. Specificity of Aspartate Aminotransferases from Leguminous Plants for 4-Substituted Glutamic Acids 1

    PubMed Central

    Winter, Harry C.; Dekker, Eugene E.

    1989-01-01

    Aspartate aminotransferase (glutamate-oxalacetate transaminase) was partially purified from extracts of germinating seeds of peanut (Arachis hypogaea), honey locust (Gleditsia triacanthos), soybean (Glycine max), and Sophora japonica. The ability of these enzyme preparations, as well as aspartate aminotransferase purified from pig heart cytosol, to use 4-substituted glutamic acids as amino group donors and their corresponding 2-oxo acids as amino group acceptors in the aminotransferase reaction was measured. All 4-substituted glutamic acid analogs tested were poorer substrates than was glutamate or 2-oxoglutarate. 2-Oxo-4-methyleneglutarate was least effective (lowest relative Vm/Km) as a substrate for the enzyme from peanuts and honey locust, which are the two species studied that accumulate 4-methyleneglutamic acid and 4-methyleneglutamine. Of the different aminotransferases tested, the enzyme from honey locust was the least active with 2-oxo-4-hydroxy-4-methylglutarate, the corresponding amino acid of which also accumulates in that species. These results suggest that transamination of 2-oxo-4-substituted glutaric acids is not involved in the biosynthesis of the corresponding 4-substituted glutamic acids in these species. Rather, accumulation of certain 4-substituted glutamic acids in these instances may be, in part, the result of the inefficacy of their transamination by aspartate aminotransferase. PMID:16666674

  15. Kinetic studies of the uptake of aspartate aminotransferase and malate dehydrogenase into mitochondria in vitro.

    PubMed Central

    Marra, E; Passarella, S; Casamassima, E; Perlino, E; Doonan, S; Quagliariello, E

    1985-01-01

    Kinetic measurements of the uptake of native mitochondrial aspartate aminotransferase and malate dehydrogenase into mitochondria in vitro were carried out. The uptake of both the enzymes is essentially complete in 1 min and shows saturation characteristics. The rate of uptake of aspartate aminotransferase into mitochondria is decreased by malate dehydrogenase, and vice versa. The inhibition is exerted by isoenzyme remaining outside the mitochondria rather than by isoenzyme that has been imported. The thiol compound beta-mercaptoethanol decreases the rate of uptake of the tested enzymes; inhibition is a result of interaction of beta-mercaptoethanol with the mitochondria and not with the enzymes themselves. The rate of uptake of aspartate aminotransferase is inhibited non-competitively by malate dehydrogenase, but competitively by beta-mercaptoethanol. The rate of uptake of malate dehydrogenase is inhibited non-competitively by aspartate aminotransferase and by beta-mercaptoethanol. beta-Mercaptoethanol prevents the inhibition of the rate of uptake of malate dehydrogenase by aspartate aminotransferase. These results are interpreted in terms of a model system in which the two isoenzymes have separate but interacting binding sites within a receptor in the mitochondrial membrane system. PMID:4015628

  16. Nutritional aspects of human lactation*

    PubMed Central

    Thomson, A. M.; Black, A. E.

    1975-01-01

    This paper reviews the literature on the incidence and duration of breast-feeding in various countries, the volume and composition of breast milk, the health and nutrition of breast-fed babies as judged by growth and morbidity, maternal nutritional requirements during lactation, and the effect of prolonged lactation on maternal health. It appears that lactation can be as well sustained by impoverished as by affluent mothers, and that even in communities where malnutrition is common the average growth of infants is satisfactory up to the age of about 3 months on a diet of breast milk alone. Breast milk appears to have specific anti-infective properties, but prolonged breast-feeding will not prevent infections among older infants reared in a poor environment. The authors believe that breast-feeding is the best form of nutrition for the young infant and deplore its decline in modern industrial societies. The recommendations of various FAO/WHO Expert Groups on nutritional intakes during lactation are summarized. The need for an increased daily energy intake of 4.2 MJ (1 000 kcal) is questioned, and an increase of 2.5 MJ (600 kcal) is suggested. Data on the effect of prolonged lactation on the health of the mother are scanty; body weight appears to be maintained even among poorly nourished mothers. The authors stress the need for well-planned and technically adequate studies of the material and psychological factors involved in breast feeding. PMID:816479

  17. Midtrimester abortion by ethacridine lactate.

    PubMed

    Goswami, B K; Raha, A; Gupta, A; Mukherjee, K

    1982-07-01

    This article discusses a clinical trial with the abortifacient agent ethacridine lactate as it was used for midtrimester abortion in Calcutta during the period January-July 1980. Results are then compared with intraamniotic hypertonic saline. 130 subjects were divided into 2 groups--Group 1 (60 women) were terminated with ethacridine lactate and group 2 (70 women) were terminated with saline. In cases where the patient complained of pain, analgesia was administered. In both groups, the largest concentration of women fell in the age groups 16-20 and 21-25. Similarly, single women were the largest representation in both groups although the saline group included more widows. Ethacridine lactate can be administered earlier in the 2nd trimester than saline. With it, expulsion occurred within 36 hours in 56.6% of the cases as compared with 22.9% in group 2. Both groups required the same amount of assistance with oxytocin. In group 1, there were only 3 cases (5%) of minor complications whereas in group 2, 19 cases (27.1%) developed complications. This alone strongly recommends ethacridine lactate as the preferred abortifacient. The success rate was 98%. Thus, ethacridine lactate appears to be a safe and effective agent for pregnancy termination during the 2nd trimester. PMID:7142727

  18. Hepatocellular Carcinoma Risk of Compensated Cirrhosis Patients with Elevated HBV DNA Levels according to Serum Aminotransferase Levels

    PubMed Central

    Lee, Junggyu; Sinn, Dong Hyun; Kim, Jung Hee; Gwak, Geum-Youn; Kim, Hye Seung; Jung, Sin-Ho; Paik, Yong-Han; Choi, Moon Seok; Lee, Joon Hyeok; Koh, Kwang Cheol; Yoo, Byung Chul

    2015-01-01

    Sometimes, hepatitis B virus (HBV)-related cirrhotic patients with normal aminotransferase levels are closely followed-up for the elevation of aminotransferase levels instead of prompt antiviral therapy (AVT). We analyzed the long-term hepatocellular carcinoma (HCC) risk according to the aminotransferase levels in a retrospective cohort of 1,468 treatment-naïve, HBV-related, compensated cirrhosis patients with elevated HBV DNA levels (≥2,000 IU/mL). Based on aminotransferase levels, patients were categorized into normal (< 40 U/L, n = 364) and elevated group (≥40 U/L, n = 1,104). During a median of 5.3 yr of follow-up (range: 1.0-8.2 yr), HCC developed in 296 (20%) patients. The 5-yr cumulative HCC incidence rate was higher in patients with elevated aminotransferase level, but was not low in normal aminotransferase level (17% vs. 14%, P = 0.004). During the follow-up, 270/364 (74%) patients with normal aminotransferase levels experienced elevation of aminotransferase levels, and AVT was initiated in 1,258 (86%) patients. Less patients with normal aminotransferase levels received AVT (70% vs. 91%, P < 0.001) and median time to start AVT was longer (17.9 vs. 2.4 months, P < 0.001). AVT duration was an independent factor associated with HCC, and median duration of AVT was shorter (4.0 vs. 2.6 yr, P < 0.001) in patients with normal aminotransferase levels. The HCC risk of compensated cirrhosis patients with normal aminotransferase level is not low, and AVT duration is associated with lowered HCC risk, indicating that prompt AVT should be strongly considered even for those with normal aminotransferase levels. PMID:26539006

  19. Expression of an L-alanine dehydrogenase gene in Zymomonas mobilis and excretion of L-alanine

    SciTech Connect

    Uhlenbusch, I.; Sahm, H.; Sprenger, G.A. )

    1991-05-01

    Gene alaD for L-alanine dehydrogenase from Bacillus sphaericus was cloned and introduced into Z. mobilis. Under the control of the strong promoter of the pyruvate decarboxylase (pdc) gene, the enzyme was expressed up to a specific activity of nearly 1 {mu}mol {center dot} min{sup {minus}1} {center dot} mg of protein{sup {minus}1} in recombinant cells. As a result of this high L-alanine dehydrogenase activity, growing cells excreted up to 10 mmol of alanine per 280 mmol of glucose utilized into a mineral salts medium. By the addition of 85 mM NH{sub 4}{sup +} to the medium, growth of the recombinant cells stopped, and up to 41 mmol of alanine was secreted. As alanine dehydrogenase competed with pyruvate decarboxylase (PDC) for the same substrate (pyruvate), PDC activity was reduced by starvation for the essential PDC cofactor thiamine PP{sub i}. A thiamine auxotrophy mutant of Z. mobilis which carried the alaD gene was starved for 40 h in glucose-supplemented mineral salts medium and then shifted to mineral salts medium with 85 mM NH {sub 4}{sup +} and 280 mmol of glucose. The recombinants excreted up to 84 mmol of alanine over 25 h. Alanine excretion proceeded at an initial velocity of 238 nmol {center dot} min{sup {minus}1} {center dot} mg(dry weight){sup {minus}1}. Despite this high activity, the excretion rate seemed to be a limiting factor, as the intracellular concentration of alanine was as high as 260 mM at the beginning of the excretion phase and decreased to 80 to 90 mM over 24 h.

  20. EFFECT OF SHORT-TERM EXPOSURE TO THREE CHEMICALS ON THE BLOOD CHEMISTRY OF THE PINFISH (LAGODON RHOMBOIDES)

    EPA Science Inventory

    Injections of 3 ml/kg CCl4 caused significant elevations in the CC14 serum enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LD-L). erum lipids and total protein were significantly lower, while serum glucose ...

  1. Structure of D-alanine-D-alanine ligase from Yersinia pestis: nucleotide phosphate recognition by the serine loop.

    PubMed

    Tran, Huyen Thi; Hong, Myoung Ki; Ngo, Ho Phuong Thuy; Huynh, Kim Hung; Ahn, Yeh Jin; Wang, Zhong; Kang, Lin Woo

    2016-01-01

    D-Alanyl-D-alanine is an essential precursor of bacterial peptidoglycan and is synthesized by D-alanine-D-alanine ligase (DDL) with hydrolysis of ATP; this reaction makes DDL an important drug target for the development of antibacterial agents. Five crystal structures of DDL from Yersinia pestis (YpDDL) were determined at 1.7-2.5 Å resolution: apo, AMP-bound, ADP-bound, adenosine 5'-(β,γ-imido)triphosphate-bound, and D-alanyl-D-alanine- and ADP-bound structures. YpDDL consists of three domains, in which four loops, loop 1, loop 2 (the serine loop), loop 3 (the ω-loop) and loop 4, constitute the binding sites for two D-alanine molecules and one ATP molecule. Some of them, especially the serine loop and the ω-loop, show flexible conformations, and the serine loop is mainly responsible for the conformational change in substrate nucleotide phosphates. Enzyme-kinetics assays were carried out for both the D-alanine and ATP substrates and a substrate-binding mechanism was proposed for YpDDL involving conformational changes of the loops. PMID:26894530

  2. Antipsychotics in pregnancy and lactation

    PubMed Central

    Babu, Girish N.; Desai, Geetha; Chandra, Prabha S.

    2015-01-01

    Research on psychotropic medications during pregnancy and lactation is limited as often involves complex ethical issues. Information on safety of psychotropic drugs during these critical phases is either inconclusive or undetermined. Many women with severe mental illness have unplanned pregnancies and require antipsychotic medication during pregnancy and lactation. Multiple issues have to be considered while choosing safe treatments for pregnant and lactating women and the best approach is to individualize the treatment. Medication should be guided primarily by its safety data and by the psychiatric history of the patient. Important issues to be kept in mind include pre-pregnancy counseling for all women, including planning pregnancies; folate supplementation, discussion with patient and family regarding options, and active liaison with obstetricians, ultrasonologists and pediatricians. Whenever possible, non-pharmacological approaches should be used in addition. PMID:26330648

  3. Selective permeability of rat liver mitochondria to purified aspartate aminotransferases in vitro.

    PubMed Central

    Marra, E; Doonan, S; Saccone, C; Quagliariello, E

    1977-01-01

    1. A method was devised to allow determination of intramitochondrial aspartate amino-transferase activity in suspensions of intact mitochondria. 2. Addition of purified rat liver mitochondrial aspartate aminotransferase to suspensions of rat liver mitochondria caused an apparent increase in the intramitochondrial enzyme activity. No increase was observed when the mitochondria were preincubated with the purified cytoplasmic isoenzyme. 3. These results suggest that mitochondrial aspartate aminotransferase, but not the cytoplasmic isoenzyme, is able to pass from solution into the matrix of intact rat liver mitochondria in vitro. 4. This system may provide a model for studies of the little-understood processes by which cytoplasmically synthesized components are incorporated into mitochondria in vivo. PMID:883959

  4. Lactational infertility in family planning.

    PubMed

    Short, R V

    1993-04-01

    The contraceptive effect of breast-feeding is the single most important determinant of human population growth rates in traditional societies without access to modern forms of contraception; lactational amenorrhoea is Nature's contraceptive. Even today, breast-feeding still prevents more pregnancies than all modern forms of contraception in many developing countries. Afferent neural inputs from the nipple pass via the spinal cord to the hypothalamus, where they cause a local release of beta endorphin. This acts to depress GnRH secretion, thereby inhibiting pituitary gonadotrophin secretion, ovarian follicular development, ovulation and menstruation. The hypothalamic beta endorphin release also inhibits dopamine production, resulting in increased pituitary prolactin secretion. The higher the suckling frequency, the more beta endorphin that is released and hence the longer the duration of lactational amenorrhoea. Lactational amenorrhoea can be relied up to give over 98% contraceptive protection to breast-feeding women in the first 6 months postpartum, regardless of their nutritional status or the time of first supplement introduction to the baby. This is because the first postpartum menstruation usually precedes the first ovulation during these early months. Once menstruation has resumed, lactation's contraceptive effect can no longer be relied upon, even though the woman continues to breast-feed. In breast-feeding women whose amenorrhoea extends beyond 6 months, there is an increasing tendency for the first ovulation to precede the first menstruation, thereby decreasing the reliability of lactational amenorrhoea as a contraceptive. Nevertheless, many women who continue to breast-feed may still have up to 1-2 years of good contraceptive protection from prolonged lactational amenorrhoea.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8489757

  5. EPR/alanine dosimetry for two therapeutic proton beams

    NASA Astrophysics Data System (ADS)

    Marrale, Maurizio; Carlino, Antonio; Gallo, Salvatore; Longo, Anna; Panzeca, Salvatore; Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony

    2016-02-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a "quenching" effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for "in vivo" dosimetry in clinical proton beams.

  6. Probing lactate secretion in tumours with hyperpolarised NMR.

    PubMed

    Durst, Markus; Koellisch, Ulrich; Daniele, Valeria; Steiger, Katja; Schwaiger, Markus; Haase, Axel; Menzel, Marion I; Schulte, Rolf F; Aime, Silvio; Reineri, Francesca

    2016-08-01

    Most tumours exhibit a high rate of glycolysis and predominantly produce energy by lactic acid fermentation. To maintain energy production and prevent toxicity, the lactate generated needs to be rapidly transported out of the cell. This is achieved by monocarboxylate transporters (MCTs), which therefore play an essential role in cancer metabolism and development. In vivo experiments were performed on eight male Fisher F344 rats bearing a subcutaneous mammary carcinoma after injection of hyperpolarised [1-(13) C]pyruvate. A Gd(III)DO3A complex that binds to pyruvate and its metabolites was used to efficiently destroy the extracellular magnetisation after hyperpolarised lactate had been formed. Moreover, a pulse sequence including a frequency-selective saturation pulse was designed so that the pyruvate magnetisation could be destroyed to exclude effects arising from further conversion. Given this preparation, metabolite transport out of the cell manifested as additional decay and apparent cell membrane transporter rates could thus be obtained using a reference measurement without a relaxation agent. In addition to slice-selective spectra, spatially resolved maps of apparent membrane transporter activity were acquired using a single-shot spiral gradient readout. A considerable increase in decay rate was detected for lactate, indicating rapid transport out of the cell. The alanine signal was unaltered, which corresponds to a slower efflux rate. This technique could allow for better understanding of tumour metabolism and progression, and enable treatment response measurements for MCT-targeted cancer therapies. Moreover, it provides vital insights into the signal kinetics of hyperpolarised [1-(13) C]pyruvate examinations. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27348729

  7. Dysferlin-Deficient Muscular Dystrophy Identified Through Laboratory Testing for Elevated Aminotransferases

    PubMed Central

    Achdjian, Houry; Usta, Yousef; Nanda, Rakesh

    2016-01-01

    We present a 24-year-old combat veteran who underwent extensive work-up for elevated aminotransferases, including liver biopsy, with no underlying pathology identified. Subsequent investigations showed elevated creatinine kinase and aldolase. The patient was later diagnosed with biopsy-proven dysferlin-deficient muscular dystrophy. Persistent transaminase elevation despite negative liver work-up should prompt clinicians to consider extrahepatic sources of enzyme elevation. Promptly correlating aminotransferase elevation with musculoskeletal pathology may present an opportunity for clinicians to detect myopathies such as muscular dystrophy in their preclinical stages. PMID:26958568

  8. Biochemical and Structural Characterization of a Ureidoglycine Aminotransferase in the Klebsiella pneumoniae Uric Acid Catabolic Pathway

    SciTech Connect

    French, Jarrod B.; Ealick, Steven E.

    2010-09-03

    Many plants, fungi, and bacteria catabolize allantoin as a mechanism for nitrogen assimilation. Recent reports have shown that in plants and some bacteria the product of hydrolysis of allantoin by allantoinase is the unstable intermediate ureidoglycine. While this molecule can spontaneously decay, genetic analysis of some bacterial genomes indicates that an aminotransferase may be present in the pathway. Here we present evidence that Klebsiella pneumoniae HpxJ is an aminotransferase that preferentially converts ureidoglycine and an {alpha}-keto acid into oxalurate and the corresponding amino acid. We determined the crystal structure of HpxJ, allowing us to present an explanation for substrate specificity.

  9. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5311 Ferrous lactate. (a) Product. Ferrous lactate. (b) Conditions of use. This...

  10. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... prepared by reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid.... (1996), pp. 154 to 155, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  11. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron... to 155, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part...

  12. The structure of alanine racemase from Acinetobacter baumannii

    PubMed Central

    Davis, Emily; Scaletti-Hutchinson, Emma; Opel-Reading, Helen; Nakatani, Yoshio; Krause, Kurt L.

    2014-01-01

    Acinetobacter baumannii is an opportunistic Gram-negative bacterium which is a common cause of hospital-acquired infections. Numerous antibiotic-resistant strains exist, emphasizing the need for the development of new antimicrobials. Alanine racemase (Alr) is a pyridoxal 5′-phosphate dependent enzyme that is responsible for racemization between enantiomers of alanine. As d-alanine is an essential component of the bacterial cell wall, its inhibition is lethal to prokaryotes, making it an excellent antibiotic drug target. The crystal structure of A. baumannii alanine racemase (AlrAba) from the highly antibiotic-resistant NCTC13302 strain has been solved to 1.9 Å resolution. Comparison of AlrAba with alanine racemases from closely related bacteria demonstrates a conserved overall fold. The substrate entryway and active site of the enzymes were shown to be highly conserved. The structure of AlrAba will provide the template required for future structure-based drug-design studies. PMID:25195891

  13. Caramelization of maltose solution in presence of alanine.

    PubMed

    Fadel, H H M; Farouk, A

    2002-01-01

    Two solutions of maltose in water were used to prepare caramels. Alanine as a catalyst was added to one of these solutions. The caramelization was conducted at 130 degrees C for total time period 90 minutes. Convenient samples were taken of each caramel solution every 30 min and subjected to sensory analysis and isolation of volatile components. The odour and colour sensory tests were evaluated according to the international standard methods (ISO). The results showed that, the presence of alanine gave rise to a high significant (P < 0.01) decrease in acid attributes and remarkable increase in the sweet and caramel attributes, which are the most important caramel notes. On the other hand the increase in heating time in presence of alanine as a catalyst resulted in a high significant (P < 0.01) increase in the browning rate of caramel solution. The new technique Solid Phase Micro Extraction (SPME) was used for trapping the volatile components in the headspace of each caramel samples followed by thermal desorption and GC and GC - MS analysis. The 5-hydroxymethyl-2-furfural (HMF), the main characteristic caramel product, showed its highest value in sample containing alanine after heating for 60 minutes. The best sensory results of the sample contains alanine were confirmed by the presence of high concentrations of the most potent odorants of caramel besides to the formation of some volatile compounds have caramel like flavours such as 2-acetyl pyrrole, 2-furanones and 1-(2-furanyl)1,2-propandione. PMID:12395187

  14. Is lactation nature's contraceptive? Data from Samoa.

    PubMed

    Fitzgerald, M H

    1992-01-01

    Data from a Samoan menstruation study suggest that lactation, even intensive on-demand lactation, does not inhibit menstruation or conception. This paper explores the applied and theoretical implications of continuing to accept lactation as a universally effective fertility control mechanism. Such thinking can have disastrous implications for family planning programs, and it keeps us from challenging long-held assumptions about lactation's role in population growth in early populations. PMID:1514124

  15. The origin and evolution of lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of mammary glands are the defining morphological feature of mammals, and a successful lactation is crucial to mammalian reproductive strategies. Among mammalian species, the nature of lactation and the composition of milk vary greatly. The evolution of lactation and its diversity amon...

  16. 21 CFR 582.1207 - Calcium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium lactate. 582.1207 Section 582.1207 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1207 Calcium lactate. (a) Product. Calcium lactate. (b) Conditions of use. This substance...

  17. Morphosynthesis of alanine mesocrystals by pH control.

    PubMed

    Ma, Yurong; Cölfen, Helmut; Antonietti, Markus

    2006-06-01

    Crystallization of DL-alanine is studied as a single polymorph model case to analyze the different modes of crystallization of polar organic molecules in absence of any structure directing additives. Depending on supersaturation, which is controlled either by temperature or by pH, and in the absence of additives, crystallization by mesoscale assembly of nanoparticles is found over a wide range of conditions, leading to so-called mesocrystals. This supplements the classical molecule-based crystallization mechanism, which is identified at lower supersaturations and at pH values away from the isoelectric point (IEP). The resulting alanine crystals are characterized by SEM, XRD, and single-crystal analysis. Time-resolved conductivity measurements and dynamic light scattering of the reaction solutions reveal information about precursor structures and reaction kinetics. A formation mechanism is proposed for the alanine mesocrystals. PMID:16771332

  18. First-principles studies of pure and fluorine substituted alanines

    NASA Astrophysics Data System (ADS)

    Ahmad, Sardar; Vaizie, Hamide; Rahnamaye Aliabad, H. A.; Ahmad, Rashid; Khan, Imad; Ali, Zahid; Jalali-Asadabadi, S.; Ahmad, Iftikhar; Khan, Amir Abdullah

    2016-05-01

    This paper communicates the structural, electronic and optical properties of L-alanine, monofluoro and difluoro substituted alanines using density functional calculations. These compounds exist in orthorhombic crystal structure and the calculated structural parameters such as lattice constants, bond angles and bond lengths are in agreement with the experimental results. L-alanine is an indirect band gap insulator, while its fluorine substituted compounds (monofluoroalanine and difluoroalanine) are direct band gap insulators. The substitution causes reduction in the band gap and hence these optically tailored direct wide band gap materials have enhanced optical properties in the ultraviolet (UV) region of electromagnetic spectrum. Therefore, optical properties like dielectric function, refractive index, reflectivity and energy loss function are also investigated. These compounds have almost isotropic nature in the lower frequency range while at higher energies, they have a significant anisotropic nature.

  19. Structural Insights into a Novel Class of Aspartate Aminotransferase from Corynebacterium glutamicum.

    PubMed

    Son, Hyeoncheol Francis; Kim, Kyung-Jin

    2016-01-01

    Aspartate aminotransferase from Corynebacterium glutamicum (CgAspAT) is a PLP-dependent enzyme that catalyzes the production of L-aspartate and α-ketoglutarate from L-glutamate and oxaloacetate in L-lysine biosynthesis. In order to understand the molecular mechanism of CgAspAT and compare it with those of other aspartate aminotransferases (AspATs) from the aminotransferase class I, we determined the crystal structure of CgAspAT. CgAspAT functions as a dimer, and the CgAspAT monomer consists of two domains, the core domain and the auxiliary domain. The PLP cofactor is found to be bound to CgAspAT and stabilized through unique residues. In our current structure, a citrate molecule is bound at the active site of one molecule and mimics binding of the glutamate substrate. The residues involved in binding of the PLP cofactor and the glutamate substrate were confirmed by site-directed mutagenesis. Interestingly, compared with other AspATs from aminotransferase subgroup Ia and Ib, CgAspAT exhibited unique binding sites for both cofactor and substrate; moreover, it was found to have unusual structural features in the auxiliary domain. Based on these structural differences, we propose that CgAspAT does not belong to either subgroup Ia or Ib, and can be categorized into a subgroup Ic. The phylogenetic tree and RMSD analysis also indicates that CgAspAT is located in an independent AspAT subgroup. PMID:27355211

  20. Structure Expression and Function of kynurenine Aminotransferases in Human and Rodent Brains

    SciTech Connect

    Q Han; T Cai; D Tagle; J Li

    2011-12-31

    Kynurenine aminotransferases (KATs) catalyze the synthesis of kynurenic acid (KYNA), an endogenous antagonist of N-methyl-D: -aspartate and alpha 7-nicotinic acetylcholine receptors. Abnormal KYNA levels in human brains are implicated in the pathophysiology of schizophrenia, Alzheimer's disease, and other neurological disorders. Four KATs have been reported in mammalian brains, KAT I/glutamine transaminase K/cysteine conjugate beta-lyase 1, KAT II/aminoadipate aminotransferase, KAT III/cysteine conjugate beta-lyase 2, and KAT IV/glutamic-oxaloacetic transaminase 2/mitochondrial aspartate aminotransferase. KAT II has a striking tertiary structure in N-terminal part and forms a new subgroup in fold type I aminotransferases, which has been classified as subgroup Iepsilon. Knowledge regarding KATs is vast and complex; therefore, this review is focused on recent important progress of their gene characterization, physiological and biochemical function, and structural properties. The biochemical differences of four KATs, specific enzyme activity assays, and the structural insights into the mechanism of catalysis and inhibition of these enzymes are discussed.

  1. Structural Insights into a Novel Class of Aspartate Aminotransferase from Corynebacterium glutamicum

    PubMed Central

    Son, Hyeoncheol Francis; Kim, Kyung-Jin

    2016-01-01

    Aspartate aminotransferase from Corynebacterium glutamicum (CgAspAT) is a PLP-dependent enzyme that catalyzes the production of L-aspartate and α-ketoglutarate from L-glutamate and oxaloacetate in L-lysine biosynthesis. In order to understand the molecular mechanism of CgAspAT and compare it with those of other aspartate aminotransferases (AspATs) from the aminotransferase class I, we determined the crystal structure of CgAspAT. CgAspAT functions as a dimer, and the CgAspAT monomer consists of two domains, the core domain and the auxiliary domain. The PLP cofactor is found to be bound to CgAspAT and stabilized through unique residues. In our current structure, a citrate molecule is bound at the active site of one molecule and mimics binding of the glutamate substrate. The residues involved in binding of the PLP cofactor and the glutamate substrate were confirmed by site-directed mutagenesis. Interestingly, compared with other AspATs from aminotransferase subgroup Ia and Ib, CgAspAT exhibited unique binding sites for both cofactor and substrate; moreover, it was found to have unusual structural features in the auxiliary domain. Based on these structural differences, we propose that CgAspAT does not belong to either subgroup Ia or Ib, and can be categorized into a subgroup Ic. The phylogenetic tree and RMSD analysis also indicates that CgAspAT is located in an independent AspAT subgroup. PMID:27355211

  2. A stereo-inverting D-phenylglycine aminotransferase from Pseudomonas stutzeri ST-201: purification, characterization and application for D-phenylglycine synthesis.

    PubMed

    Wiyakrutta, S; Meevootisom, V

    1997-07-01

    D-phenylglycine aminotransferase (D-PhgAT) from a newly isolated soil bacterium, Pseudomonas stutzeri ST-201, was purified to electrophoretic homogeneity and characterized. The molecular weight (M(r)) of the native enzyme was estimated to be 92,000. It is composed of two subunits identical in molecular weight (M(r)) = 47,500). The isoelectric point (pI) of the native enzyme was 5.0. The enzyme catalyzed reversible transamination specific for D-phenylglycine or D-4-hydroxyphenylglycine in which 2-oxoglutarate was an exclusive amino group acceptor and was converted into L-glutamic acid. Neither the D- nor L-isomer of phenylalanine, tyrosine, alanine, valine, leucine, isoleucine or serine could serve as a substrate. The enzyme was most active at alkaline pH with maximum activity at pH 9-10. The temperature for maximum activity was 35-45 degrees C. The apparent K(m) values for D-phenylglycine and for 2-oxoglutarate at 35 degrees C, pH 9.5 were 1.1 and 2.4 mM, respectively. The enzyme activity was strongly inhibited by typical inhibitors of pyridoxal phosphate-dependent enzymes. Possible application of this enzyme for synthesis of enantiomerically pure D-phenylglycine was demonstrated. PMID:9249994

  3. 200th anniversary of lactate research in muscle.

    PubMed

    Gladden, L Bruce

    2008-07-01

    This year, 2008, marks the bicentennial of research into lactate metabolism in muscle. Berzelius linked lactate accumulation to exercise in 1807/1808 when he noted the presence of lactate in the muscles of "hunted stags." Today, the exact mechanism of intramuscular lactate oxidation and the relationship of lactate dehydrogenase to mitochondria remain unresolved as animated debate surrounds the intracellular lactate shuttle. PMID:18580290

  4. Atomic Layer Deposition of L-Alanine Polypeptide

    DOE PAGESBeta

    Fu, Yaqin; Li, Binsong; Jiang, Ying-Bing; Dunphy, Darren R.; Tsai, Andy; Tam, Siu-Yue; Fan, Hongyou Y.; Zhang, Hongxia; Rogers, David; Rempe, Susan; et al

    2014-10-30

    L-Alanine polypeptide thin films were synthesized via atomic layer deposition (ALD). Rather, instead of using an amino acid monomer as the precursor, an L-alanine amino acid derivatized with a protecting group was used to prevent self-polymerization, increase the vapor pressure, and allow linear cycle-by-cycle growth emblematic of ALD. Moreover, the successful deposition of a conformal polypeptide film has been confirmed by FTIR, TEM, and Mass Spectrometry, and the ALD process has been extended to polyvaline.

  5. Stereoselective aminoacylation of a dinucleoside monophosphate by the imidazolides of DL-alanine and N-(tert-butoxycarbonyl)-DL-alanine

    NASA Technical Reports Server (NTRS)

    Profy, A. T.; Usher, D. A.

    1984-01-01

    The aminoacylation of diinosine monophosphate was studied experimentally. When the acylating agent was the imidazolide of N-(tert-butoxycarbonyl)-DL-alanine, a 40 percent enantiomeric excess of the isomer was incorporated at the 2' site and the positions of equilibrium for the reversible 2'-3' migration reaction differed for the D and L enantiomers. The reactivity of the nucleoside hydroxyl groups was found to decrease on the order 2'(3') less than internal 2' and less than 5', and the extent of the reaction was affected by the concentration of the imidazole buffer. Reaction of IpI with imidazolide of unprotected DL-alanine, by contrast, led to an excess of the D isomer at the internal 2' site. Finally, reaction with the N-carboxy anhydride of DL-alanine occurred without stereoselection. These results are found to be relevant to the study of the evolution of optical chemical activity and the origin of genetically directed protein synthesis.

  6. Point of Care Measurement of Lactate.

    PubMed

    Di Mauro, Francesca Miranda; Schoeffler, Gretchen Lee

    2016-03-01

    Lactate is generated as a consequence of anaerobic glycolysis by all tissues of the body. Increased l-lactate, the isoform produced by most mammals, reflects increased anaerobic metabolism secondary to tissue hypoperfusion or tissue hypoxia in most clinical situations, and is called type A lactic acidosis. The utility of lactate measurement and serial lactate monitoring in veterinary patients has been demonstrated in multiple studies. Blood lactate concentration is significantly elevated in many disease processes including septic peritonitis, immune-mediated hemolytic anemia, Babesiosis, trauma, gastric dilation and volvulus, and intracranial disease. Lactate clearance can be used to assess response to fluid therapy, cardiovascular therapeutics, and blood product transfusion in patients affected by type A lactic acidosis. Lactate concentration in peritoneal, pericardial, and synovial fluid can also be used as a diagnostic tool. Point of care analyzers such as the Lactate Pro, Lactate Scout, Accutrend, iSTAT, and Lactate Plus have been shown to be accurate lactate measurement instruments in small animal patients. PMID:27451047

  7. Spectrophotometric readout for an alanine dosimeter for food irradiation applications

    NASA Astrophysics Data System (ADS)

    Ebraheem, S.; Beshir, W. B.; Eid, S.; Sobhy, R.; Kovács, A.

    2003-06-01

    The alanine-electron spin resonance (EPR) readout system is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application in irradiation facilities. In this study, the use of a complex produced by dissolving irradiated L-alanine in 1,4-phenyl diammonium dichloride solution was investigated for dosimetry purposes. This complex—having a purple colour—has an increasing absorbance with increasing dose in the range of 1-20 kGy. The applicability of spectrophotometric evaluation was studied by measuring the absorbance intensity of this complex at 360 and 505 nm, respectively. Fluorimetric evaluation was also investigated by measuring the emission of the complex at 435 nm as a function of dose. The present method is easy for routine application. The effect of the dye concentration as well as the suitable amount of irradiated alanine has been studied. With respect to routine application, the stability of the product complex after its formation was also investigated.

  8. Formation of {gamma}-alumina nanorods in presence of alanine

    SciTech Connect

    Dabbagh, Hossein A.; Rasti, Elham; Yalfani, Mohammad S.; Medina, Francesc

    2011-02-15

    Graphical abstract: Nanorod aluminas with a possible hexagonal symmetry, high surface area and relatively narrow pore size distribution were obtained. Research highlights: {yields} Research highlights {yields} Boehmite was prepared using a green sol-gel process in the presence of alanine. {yields} Nanorod aluminas with a high surface area were obtained. {yields} Addition of alanine would shape the size of the holes and crevices. {yields} The morphologies of the nanorods were revealed by transmission electron microscope. -- Abstract: Boehmite and alumina nanostructures were prepared using a simple green sol-gel process in the presence of alanine in water medium at room temperature. The uncalcined (dried at 200 {sup o}C) and the calcined materials (at 500, 600 and 700 {sup o}C for 4 h) were characterized using XRD, TEM, SEM, N{sub 2} physisorption and TGA. Nanorod aluminas with a possible hexagonal symmetry, high surface area and relatively narrow pore size distribution were obtained. The surface area was enhanced and crystallization was retarded as the alanine content increased. The morphologies of the nanoparticles and nanorods were revealed by a transmission electron microscope (TEM).

  9. The unresolved puzzle why alanine extensions cause disease.

    PubMed

    Winter, Reno; Liebold, Jens; Schwarz, Elisabeth

    2013-08-01

    The prospective increase in life expectancy will be accompanied by a rise in the number of elderly people who suffer from ill health caused by old age. Many diseases caused by aging are protein misfolding diseases. The molecular mechanisms underlying these disorders receive constant scientific interest. In addition to old age, mutations also cause congenital protein misfolding disorders. Chorea Huntington, one of the most well-known examples, is caused by triplet extensions that can lead to more than 100 glutamines in the N-terminal region of huntingtin, accompanied by huntingtin aggregation. So far, nine disease-associated triplet extensions have also been described for alanine codons. The extensions lead primarily to skeletal malformations. Eight of these proteins represent transcription factors, while the nuclear poly-adenylate binding protein 1, PABPN1, is an RNA binding protein. Additional alanines in PABPN1 lead to the disease oculopharyngeal muscular dystrophy (OPMD). The alanine extension affects the N-terminal domain of the protein, which has been shown to lack tertiary contacts. Biochemical analyses of the N-terminal domain revealed an alanine-dependent fibril formation. However, fibril formation of full-length protein did not recapitulate the findings of the N-terminal domain. Fibril formation of intact PABPN1 was independent of the alanine segment, and the fibrils displayed biochemical properties that were completely different from those of the N-terminal domain. Although intranuclear inclusions have been shown to represent the histochemical hallmark of OPMD, their role in pathogenesis is currently unclear. Several cell culture and animal models have been generated to study the molecular processes involved in OPMD. These studies revealed a number of promising future therapeutic strategies that could one day improve the quality of life for the patients. PMID:23612654

  10. Lactate metabolism by pediococci isolated from cheese.

    PubMed

    Thomas, T D; McKay, L L; Morris, H A

    1985-04-01

    Pediococcus pentosaceus is commonly found among the adventitious microflora of Cheddar cheese. When this organism was incubated with L-(+)-lactate under anaerobic conditions, L-(+)-lactate was rapidly converted to D-(-)-lactate until racemic (DL) lactate was present. Under aerobic conditions this initial reaction was followed by a slower reaction resulting in the use of both lactate isomers and in the production of acetate and CO2. With intact cells the lactate oxidation system had an optimum pH of 5 to 6, depending on the initial lactate concentration. Cells grown anaerobically possessed lactate-oxidizing activity which increased two- to fourfold as sugar was exhausted from the medium. Aerobic growth further increased specific activities. Cheddar cheese was made with the deliberate addition of P. pentosaceus. When the resulting cheese was grated to expose a large surface area to O2, lactate was converted to acetate at a rate which depended on the density of pediococci in the cheese. The lactate oxidation system remained active in cheese which had been ripened for 6 months. PMID:4004222

  11. Lactate metabolism in the fetal rabbit lung

    SciTech Connect

    Engle, M.J.; Brown, D.J.; Dooley, M.

    1986-05-01

    Lactate is frequently overlooked as a potential substrate for the fetal lung, even though it is present in the fetal circulation in concentrations as high as 8 mM. These high concentrations, coupled with the relatively low levels of glucose in the fetal blood, may indicate that lactate can substitute for glucose in pulmonary energy generation and phospholipid synthesis. A series of experiments was therefore undertaken in order to investigate the role of lactate in perinatal pulmonary development. Explants from 30 day gestation fetal rabbit lungs were incubated in Krebs-Ringer bicarbonate buffer supplemented with 3 mM (U-/sup 14/C)-glucose and varying levels of lactate. In the absence of medium lactate, fetal rabbit lung explants were capable of producing lactate at a rate of approximately 200 etamoles/mg protein/hour. The addition of lactate to the bathing medium immediately reduced net lactate production and above 4 mM, fetal rabbit lung explants became net utilizers of lactate. Media lactate concentrations of 2.5 mM, 5 mM and 10 mM also decreased glucose incorporation into total tissue disaturated phosphatidylcholine by approximately 20%, 35%, and 45%, respectively. Glucose incorporation into surfactant phosphatidylcholine was also reduced by approximately 50%, when lactate was present in the incubation medium at a concentration of 5 mM. Additional experiments also revealed that fetal lung lactate dehydrogenase activity was almost twice that found in the adult rabbit lung. These data indicate that lactate may be an important carbon source for the developing lung and could be a significant component in the manufacture of surfactant phosphatidylcholine during late gestation.

  12. The N-terminal region of mature mitochondrial aspartate aminotransferase can direct cytosolic dihydrofolate reductase into mitochondria in vitro.

    PubMed

    Giannattasio, S; Azzariti, A; Marra, E; Quagliariello, E

    1994-06-30

    Two fused genes were constructed which encode for two chimeric proteins in which either 10 or 191 N-terminal amino acids of mature mitochondrial aspartate aminotransferase had been attached to the entire polypeptide chain of cytosolic dihydrofolate reductase. The precursor and mature form of mitochondrial aspartate aminotransferase, dihydrofolate reductase and both chimeric proteins were synthesized in vitro and their import into isolated mitochondria was studied. Both chimeric proteins were taken up by isolated organelles, where they became protease resistant, thus indicating the ability of the N-terminal portion of the mature moiety of the precursor of mitochondrial aspartate aminotransferase to direct cytosolic dihydrofolate reductase into mitochondria. PMID:8024546

  13. Formation of simple biomolecules from alanine in ocean by impacts

    NASA Astrophysics Data System (ADS)

    Umeda, Y.; Sekine, T.; Furukawa, Y.; Kakegawa, T.; Kobayashi, T.

    2013-12-01

    The biomolecules on the Earth are thought either to have originated from the extraterrestrial parts carried with flying meteorites or to have been formed from the inorganic materials on the Earth through given energy. From the standpoint to address the importance of impact energy, it is required to simulate experimentally the chemical reactions during impacts, because violent impacts may have occurred 3.8-4.0 Gyr ago to create biomolecules initially. It has been demonstrated that shock reactions among ocean (H2O), atmospheric nitrogen, and meteoritic constitution (Fe) can induce locally reduction environment to form simple bioorganic molecules such as ammonia and amino acid (Nakazawa et al., 2005; Furukawa et al., 2009). We need to know possible processes for alanine how chemical reactions proceed during repeated impacts and how complicated biomolecules are formed. Alanine can be formed from glycine (Umeda et al., in preparation). In this study, we carried out shock recovery experiments at pressures of 4.4-5.7 GPa to investigate the chemical reactions of alanine. Experiments were carried out with a propellant gun. Stainless steel containers (30 mm in diameter, 30 mm long) with 13C-labeled alanine aqueous solution immersed in olivine or hematite powders were used as targets. Air gap was present in the sample room (18 mm in diameter, 2 mm thick) behind the sample. The powder, solution, and air represent meteorite, ocean, and atmosphere on early Earth, respectively. Two powders of olivine and hematite help to keep the oxygen fugacity low and high during experiments, respectively in order to investigate the effect of oxygen fugacity on chemical processes of alanine. The recovered containers, after cleaned completely, were immersed into liquid nitrogen to freeze sample solution and then we drilled on the impact surface to extract water-soluble run products using pure water. Thus obtained products were analyzed by LC/MS for four amino acids (glycine, alanine, valine, and

  14. Structure of the Mycobacterium tuberculosis D-Alanine:D-Alanine Ligase, a Target of the Antituberculosis Drug D-Cycloserine

    SciTech Connect

    Bruning, John B.; Murillo, Ana C.; Chacon, Ofelia; Barletta, Raúl G.; Sacchettini, James C.

    2011-09-28

    D-Alanine:D-alanine ligase (EC 6.3.2.4; Ddl) catalyzes the ATP-driven ligation of two D-alanine (D-Ala) molecules to form the D-alanyl:D-alanine dipeptide. This molecule is a key building block in peptidoglycan biosynthesis, making Ddl an attractive target for drug development. D-Cycloserine (DCS), an analog of D-Ala and a prototype Ddl inhibitor, has shown promise for the treatment of tuberculosis. Here, we report the crystal structure of Mycobacterium tuberculosis Ddl at a resolution of 2.1 {angstrom}. This structure indicates that Ddl is a dimer and consists of three discrete domains; the ligand binding cavity is at the intersection of all three domains and conjoined by several loop regions. The M. tuberculosis apo Ddl structure shows a novel conformation that has not yet been observed in Ddl enzymes from other species. The nucleotide and D-alanine binding pockets are flexible, requiring significant structural rearrangement of the bordering regions for entry and binding of both ATP and D-Ala molecules. Solution affinity and kinetic studies showed that DCS interacts with Ddl in a manner similar to that observed for D-Ala. Each ligand binds to two binding sites that have significant differences in affinity, with the first binding site exhibiting high affinity. DCS inhibits the enzyme, with a 50% inhibitory concentration (IC{sub 50}) of 0.37 mM under standard assay conditions, implicating a preferential and weak inhibition at the second, lower-affinity binding site. Moreover, DCS binding is tighter at higher ATP concentrations. The crystal structure illustrates potential drugable sites that may result in the development of more-effective Ddl inhibitors.

  15. Exogenous lactate supply affects lactate kinetics of rainbow trout, not swimming performance

    PubMed Central

    Omlin, Teye; Langevin, Karolanne

    2014-01-01

    Intense swimming causes circulatory lactate accumulation in rainbow trout because lactate disposal (Rd) is not stimulated as strongly as lactate appearance (Ra). This mismatch suggests that maximal Rd is limited by tissue capacity to metabolize lactate. This study uses exogenous lactate to investigate what constrains maximal Rd and minimal Ra. Our goals were to determine how exogenous lactate affects: 1) Ra and Rd of lactate under baseline conditions or during graded swimming, and 2) exercise performance (critical swimming speed, Ucrit) and energetics (cost of transport, COT). Results show that exogenous lactate allows swimming trout to boost maximal Rd lactate by 40% and reach impressive rates of 56 μmol·kg−1·min−1. This shows that the metabolic capacity of tissues for lactate disposal is not responsible for setting the highest Rd normally observed after intense swimming. Baseline endogenous Ra (resting in normoxic water) is not significantly reduced by exogenous lactate supply. Therefore, trout have an obligatory need to produce lactate, either as a fuel for oxidative tissues and/or from organs relying on glycolysis. Exogenous lactate does not affect Ucrit or COT, probably because it acts as a substitute for glucose and lipids rather than extra fuel. We conclude that the observed 40% increase in Rd lactate is made possible by accelerating lactate entry into oxidative tissues via monocarboxylate transporters (MCTs). This observation together with the weak expression of MCTs and the phenomenon of white muscle lactate retention show that lactate metabolism of rainbow trout is significantly constrained by transmembrane transport. PMID:25121611

  16. Ontogenic changes of kynurenine aminotransferase I activity and its expression in the chicken retina.

    PubMed

    Rejdak, Robert; Zielinska, Elzbieta; Shenk, Yana; Turski, Waldemar A; Okuno, Etsuo; Zarnowski, Tomasz; Zagorski, Zbigniew; Zrenner, Eberhart; Kohler, Konrad

    2003-06-01

    Kynurenine aminotransferases are key enzymes for the synthesis of kynurenic acid (KYNA), an endogenous glutamate receptor antagonist. The study described here examined ontogenic changes of kynurenine aminotransferase I (KAT I) activity and its expression in the chicken retina. KAT I activity measured on embryonic day 16 (E16) was significantly higher than at all other stages (E12, P0 and P7). Double labeling with antibodies against glutamine synthetase showed that on P7 KAT I was expressed in Müller cell endfeet and their processes in the inner retina. Since KAT I activity is high in the late embryonic stages, it is conceivable that it plays a neuromodulatory role in the retina during the late phase of embryogenesis. PMID:12782065

  17. Participation of cysteine and cystine in inactivation of tyrosine aminotransferase in rat liver homogenates.

    PubMed Central

    Buckley, W T; Milligan, L P

    1978-01-01

    1. Inactivation of tyrosine aminotransferase was studied in rat liver homogenates. Under an O2 atmosphere with cysteine added, inactivation was rapid after a lag period of approx. 1h, whereas a N2 atmosphere extended the lag period to approx. 3h. 2. Replacement of cysteine with cystine resulted in rapid inactivation both aerobically and anaerobically. 3. Removal of the particulate fraction by centrifuging rat liver homogenates at 13,000g for 9min resulted in an aerobic lag period of 0.5h in the presence of cystine and approx. 3h in the presence of cysteine. 4. It is proposed that the stimulatory effect of cysteine on tyrosine aminotransferase inactivation occurs largely as a result of oxidation to cystine, which appears to be a more directly effective agent. PMID:33669

  18. NMR-based metabolite profiling of human milk: A pilot study of methods for investigating compositional changes during lactation.

    PubMed

    Wu, Junfang; Domellöf, Magnus; Zivkovic, Angela M; Larsson, Göran; Öhman, Anders; Nording, Malin L

    2016-01-15

    Low-molecular-weight metabolites in human milk are gaining increasing interest in studies of infant nutrition. In the present study, the milk metabolome from a single mother was explored at different stages of lactation. Metabolites were extracted from sample aliquots using either methanol/water (MeOH/H2O) extraction or ultrafiltration. Nuclear magnetic resonance (NMR) spectroscopy was used for metabolite identification and quantification, and multi- and univariate statistical data analyses were used to detect changes over time of lactation. Compared to MeOH/H2O extraction, ultrafiltration more efficiently reduced the interference from lipid and protein resonances, thereby enabling the identification and quantification of 36 metabolites. The human milk metabolomes at the early (9-24 days after delivery) and late (31-87 days after delivery) stages of lactation were distinctly different according to multi- and univariate statistics. The late lactation stage was characterized by significantly elevated concentrations of lactose, choline, alanine, glutamate, and glutamine, as well as by reduced levels of citrate, phosphocholine, glycerophosphocholine, and N-acetylglucosamine. Our results indicate that there are significant compositional changes of the human milk metabolome also in different phases of the matured lactation stage. These findings complement temporal studies on the colostrum and transitional metabolome in providing a better understanding of the nutritional variations received by an infant. PMID:26655810

  19. Expression, detection of candidate function and homology modeling for Vicia villosa ornithine δ-aminotransferase.

    PubMed

    Nada, Ahmed M K; Abd-Elhalim, Haytham M; El-Domyati, Fotouh M; Abou-Ali, Rania M I; Bahieldin, Ahmed

    2010-01-01

    The accumulation of compatible solutes during stress in plant cell is well documented. Proline is one of these solutes which accumulate in the cytosol in response to drought or salinity stress in plants. Proline has several functions during stress just like osmotic adjustment, osmoprotection, free radical scavenger and antioxidant. Ornithine δ-aminotransferase (δ-OAT) is an important enzyme in proline biosynthetic pathway. It catalyzes the transamination of ornithine to pyrroline-5-carboxylate which can be reduced into proline. Expression of ornithine δ-aminotransferase gene isolated from Vicia villosa (VvOAT) showed protein with a molecular mass of 63 KDa which is compatible with the predicted mass and after VvOAT gene delivery into E. coli host HB101, VvOAT gene enhanced its salt tolerance. Homology modeling of VvOAT was performed based on the crystal structure of the ornithine δ-aminotransferase from humans (PDB code 2OATA). With this model, a flexible docking study with the substrate and inhibitors was performed. The results indicated that PHE170 and ASN171 in VvOAT are the important determinant residues in binding as they have strong hydrogen bonding contacts with the substrate and inhibitors. All the obtained results indicated the efficiency of utilizing this gene in conferring salt tolerance. PMID:21844680

  20. Structural genes of glutamate 1-semialdehyde aminotransferase for porphyrin synthesis in a cyanobacterium and Escherichia coli.

    PubMed

    Grimm, B; Bull, A; Breu, V

    1991-01-01

    In bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (Rhodobacter) or Rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-CoA into 5-aminolevulinate as is the case in mammalian cells and yeast. In cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutamate into 5-aminolevulinate. The last step is the conversion of glutamate 1-semialdehyde into 5-aminolevulinate. Using a cDNA clone encoding glutamate 1-semialdehyde aminotransferase from barley, genes for this enzyme were cloned from Synechococcus PCC6301 and Escherichia coli and sequenced. The popC gene of E. coli, previously considered to encode 5-aminolevulinate synthase, appears to be a structural gene for glutamate 1-semialdehyde aminotransferase. Domains with identical amino acid sequences comprise 48% of the primary structure of the barley, cyanobacterial and putative E. coli glutamate 1-semialdehyde aminotransferases. The cyanobacterial and barley enzymes share 72% identical residues. The peptide containing a likely pyridoxamine phosphate binding lysine is conserved in all three protein sequences. PMID:1900346

  1. Purification and Characterization of Glutamate 1-Semialdehyde Aminotransferase from Barley Expressed in Escherichia coli.

    PubMed

    Berry-Lowe, S L; Grimm, B; Smith, M A; Kannangara, C G

    1992-08-01

    The immediate precursor in the synthesis of tetrapyrroles is Delta-aminolevulinate (ALA). ALA is synthesized from glutamate in higher plants, algae, and certain bacteria. Glutamate 1-semialdehyde aminotransferase (EC 5.4.3.8) (GSA-AT), the third enzyme involved in this metabolic pathway, catalyzes the transamination of GSA to form ALA. The gene encoding this aminotransferase has previously been isolated from barley (Hordeum vulgare) and inserted into an Escherichia coli expression vector. We describe herein the purification of this recombinant barley GSA-AT expressed in Escherichia coli. Coexpression of GroEL and GroES is required for isolation of active aminotransferase from the soluble protein fraction of Escherichia coli. Purified GSA-AT exhibits absorption maxima characteristic of vitamin B(6)-containing enzymes. GSA-AT is primarily in the pyridoxamine form when isolated and can be interconverted between this and the pyridoxal form by addition of 4,5-dioxovalerate and 4,5-diaminovalerate. The conversion of GSA to ALA under steady-state conditions exhibited typical Michaelis-Menten kinetics. Values for K(m) (d,l-GSA) and k(cat) were determined to be 25 micromolar and 0.11 per second, respectively, by nonlinear regression analysis. Stimulation of ALA synthesis by increasing concentrations of d,l-GSA at various fixed concentrations of 4,5-diaminovalerate supports the hypothesis that 4,5-diaminovalerate is the intermediate in the synthesis of ALA. PMID:16669079

  2. Uptake of aspartate aminotransferase into mitochondria in vitro depends on the transmembrane pH gradient.

    PubMed Central

    Passarella, S; Marra, E; Doonan, S; Languino, L R; Saccone, C; Quagliariello, E

    1982-01-01

    1. The effects of various inhibitors of electron transport and of oxidative phosphorylation and the effects of ionophores on the uptake of native aspartate aminotransferase into mitochondria were investigated. 2. Both antimycin and cyanide completely inhibited the uptake of the enzyme. On the other hand, uptake was stimulated to ATP and by oligomycin; however, the stimulation by ATP is inhibited by oligomycin. 3. The effects of ionophores of the valinomycin type in media containing K+ ions depended on the conditions used. Valinomycin alone stimulated the uptake of the enzyme, but in the presence of phosphate ions uptake was abolished. Nonactin was without effect at a low K+ concentration, but was stimulatory at 100 mM-KCl. Gramicidin also stimulated the uptake process. 4. Nigericin completely abolished uptake of aspartate aminotransferase into mitochondria. 5. The uptake of te enzyme was decreased by 18% in the absence of inhibitors or ionophores when the external pH was increased from 6.9 to 7.6. 6. These results indicate that ATP is not directly involved in the uptake of aspartate aminotransferase into mitochondria, neither is there a requirement for a cation gradient. Rather the uptake depends on the maintenance of a pH gradient across the mitochondrial inner membrane. PMID:7092821

  3. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any integer up to 5, CAS Reg. No. 814-80-2) is prepared commercially by the neutralization of lactic acid with...

  4. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  5. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  6. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactate. 184.1207 Section 184.1207 Food and... Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any... calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of the Food...

  7. 21 CFR 184.1639 - Potassium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium lactate. 184.1639 Section 184.1639 Food... Specific Substances Affirmed as GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and...

  8. 21 CFR 184.1639 - Potassium lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium lactate. 184.1639 Section 184.1639 Food... GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and is prepared commercially...

  9. 21 CFR 184.1639 - Potassium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium lactate. 184.1639 Section 184.1639 Food... Specific Substances Affirmed as GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and...

  10. 21 CFR 184.1639 - Potassium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium lactate. 184.1639 Section 184.1639 Food... Specific Substances Affirmed as GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and...

  11. 21 CFR 184.1639 - Potassium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium lactate. 184.1639 Section 184.1639 Food... Specific Substances Affirmed as GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and...

  12. Cerebral Lactate Metabolism After Traumatic Brain Injury.

    PubMed

    Patet, Camille; Suys, Tamarah; Carteron, Laurent; Oddo, Mauro

    2016-04-01

    Cerebral energy dysfunction has emerged as an important determinant of prognosis following traumatic brain injury (TBI). A number of studies using cerebral microdialysis, positron emission tomography, and jugular bulb oximetry to explore cerebral metabolism in patients with TBI have demonstrated a critical decrease in the availability of the main energy substrate of brain cells (i.e., glucose). Energy dysfunction induces adaptations of cerebral metabolism that include the utilization of alternative energy resources that the brain constitutively has, such as lactate. Two decades of experimental and human investigations have convincingly shown that lactate stands as a major actor of cerebral metabolism. Glutamate-induced activation of glycolysis stimulates lactate production from glucose in astrocytes, with subsequent lactate transfer to neurons (astrocyte-neuron lactate shuttle). Lactate is not only used as an extra energy substrate but also acts as a signaling molecule and regulator of systemic and brain glucose use in the cerebral circulation. In animal models of brain injury (e.g., TBI, stroke), supplementation with exogenous lactate exerts significant neuroprotection. Here, we summarize the main clinical studies showing the pivotal role of lactate and cerebral lactate metabolism after TBI. We also review pilot interventional studies that examined exogenous lactate supplementation in patients with TBI and found hypertonic lactate infusions had several beneficial properties on the injured brain, including decrease of brain edema, improvement of neuroenergetics via a "cerebral glucose-sparing effect," and increase of cerebral blood flow. Hypertonic lactate represents a promising area of therapeutic investigation; however, larger studies are needed to further examine mechanisms of action and impact on outcome. PMID:26898683

  13. 21 CFR 184.1768 - Sodium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium lactate. 184.1768 Section 184.1768 Food and... Substances Affirmed as GRAS § 184.1768 Sodium lactate. (a) Sodium lactate (C3H5O3Na, CAS Reg. No. 72-17-3) is the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid...

  14. 21 CFR 184.1768 - Sodium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium lactate. 184.1768 Section 184.1768 Food and... Substances Affirmed as GRAS § 184.1768 Sodium lactate. (a) Sodium lactate (C3H5O3Na, CAS Reg. No. 72-17-3) is the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid...

  15. 21 CFR 184.1768 - Sodium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium lactate. 184.1768 Section 184.1768 Food and... Substances Affirmed as GRAS § 184.1768 Sodium lactate. (a) Sodium lactate (C3H5O3Na, CAS Reg. No. 72-17-3) is the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid...

  16. 21 CFR 184.1768 - Sodium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium lactate. 184.1768 Section 184.1768 Food and... Substances Affirmed as GRAS § 184.1768 Sodium lactate. (a) Sodium lactate (C3H5O3Na, CAS Reg. No. 72-17-3) is the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid...

  17. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O,...

  18. Lactation amenorrhea in Saudi women.

    PubMed Central

    Madani, K A; Khashoggi, R H; al-Nowaisser, A A; Nasrat, H A; Khalil, M H

    1994-01-01

    STUDY OBJECTIVE--The study aimed to investigate some aspects of breast feeding, namely-lactation amenorrhea, the average interval between pregnancies, and the extent of knowledge that an average Saudi woman has about breast feeding. DESIGN--This was a cross sectional study in which a pretested questionnaire was used to collect the information. SETTING--The study was conducted in the Taif area between January and April of 1990. Seventy nine primary health care centres participated. PARTICIPANTS--Altogether 1019 of 2400 women contacted who agreed to participate and met the criteria were studied. Eligible subjects were defined as Saudi women, between 16 and 40 years old, who came with their infants for vaccination, and had delivered between one week and 12 months previously. Each mother had at least one other child. MEASUREMENT AND MAIN RESULT--At birth, the percentage of infants who were initially breast fed was 98% but within three days of delivery over two thirds (68.9%) of the mothers gave other supplementary liquids to their infants. At the time of interview more than half (55.1%) of mothers had lactation amenorrhea. The mean (SD) lactation amenorrhea period and birth interval were 5.95 (5) and 26.8 (14.1) months, respectively. Mothers obtained information on breast feeding mainly from their doctors and television. Within families, husbands had the primary role in encouraging their wives to breast feed, followed by the mother and then by the mother in law. It was found that a high percentage (94.2%) of women had breast fed their previous child. CONCLUSION--The lack of adequate information on breast feeding and the short interval between births are local problems which should be considered by the health authorities. PMID:8051529

  19. Hemichannel-mediated release of lactate.

    PubMed

    Karagiannis, Anastassios; Sylantyev, Sergiy; Hadjihambi, Anna; Hosford, Patrick S; Kasparov, Sergey; Gourine, Alexander V

    2016-07-01

    In the central nervous system lactate contributes to the extracellular pool of readily available energy substrates and may also function as a signaling molecule which mediates communication between glial cells and neurons. Monocarboxylate transporters are believed to provide the main pathway for lactate transport across the membranes. Here we tested the hypothesis that lactate could also be released via opening of pannexin and/or functional connexin hemichannels. In acute slices prepared from the brainstem, hippocampus, hypothalamus and cortex of adult rats, enzymatic amperometric biosensors detected significant tonic lactate release inhibited by compounds, which block pannexin/connexin hemichannels and facilitated by lowering extracellular [Ca(2+)] or increased PCO2 Enhanced lactate release triggered by hypoxia was reduced by ∼50% by either connexin or monocarboxylate transporter blockers. Stimulation of Schaffer collateral fibers triggered lactate release in CA1 area of the hippocampus, which was facilitated in conditions of low extracellular [Ca(2+)], markedly reduced by blockade of connexin hemichannels and abolished by lactate dehydrogenase inhibitor oxamate. These results indicate that lactate transport across the membranes may occur via mechanisms other than monocarboxylate transporters. In the central nervous system, hemichannels may function as a conduit of lactate release, and this mechanism is recruited during hypoxia and periods of enhanced neuronal activity. PMID:26661210

  20. Selected Cytokines Serve as Potential Biomarkers for Predicting Liver Inflammation and Fibrosis in Chronic Hepatitis B Patients With Normal to Mildly Elevated Aminotransferases.

    PubMed

    Deng, Yong-Qiong; Zhao, Hong; Ma, An-Lin; Zhou, Ji-Yuan; Xie, Shi-Bin; Zhang, Xu-Qing; Zhang, Da-Zhi; Xie, Qing; Zhang, Guo; Shang, Jia; Cheng, Jun; Zhao, Wei-Feng; Zou, Zhi-Qiang; Zhang, Ming-Xiang; Wang, Gui-Qiang

    2015-11-01

    Previous studies of small cohorts have implicated several circulating cytokines with progression of chronic hepatitis B (CHB). However, to date there have been no reliable biomarkers for assessing histological liver damage in CHB patients with normal or mildly elevated alanine aminotransferase (ALT). The aim of the present study was to investigate the association between circulating cytokines and histological liver damage in a large cohort. Also, this study was designed to assess the utility of circulating cytokines in diagnosing liver inflammation and fibrosis in CHB patients with ALT less than 2 times the upper limit of normal range (ULN). A total of 227 CHB patients were prospectively enrolled. All patients underwent liver biopsy and staging by Ishak system. Patients with at least moderate inflammation showed significantly higher levels of CXCL-11, CXCL-10, and interleukin (IL)-2 receptor (R) than patients with less than moderate inflammation (P < 0.001). Patients with significant fibrosis had higher levels of IL-8 (P = 0.027), transforming growth factor alpha (TGF-α) (P = 0.011), IL-2R (P = 0.002), and CXCL-11 (P = 0.032) than the group without significant fibrosis. In addition, 31.8% and 29.1% of 151 patients with ALT < 2 × ULN had at least moderate inflammation and significant fibrosis, respectively. Multivariate analysis demonstrated that CXCL-11 was independently associated with at least moderate inflammation, and TGF-α and IL-2R independently correlated with significant fibrosis in patients with ALT < 2 × ULN. Based on certain cytokines and clinical parameters, an inflammation-index and fib-index were developed, which showed areas under the receiver operating characteristics curve (AUROC) of 0.75 (95% CI 0.66-0.84) for at least moderate inflammation and 0.82 (95% CI 0.75-0.90) for significant fibrosis, correspondingly. Compared to existing scores, fib-index was significantly superior to aspartate aminotransferase

  1. Degradation of Glycine and Alanine on Irradiated Quartz

    NASA Astrophysics Data System (ADS)

    Pawlikowski, Maciej; Benko, Aleksandra; Wróbel, Tomasz P.

    2013-04-01

    Recent researches suggest participation of minerals in the formation of life under primordial conditions. Among all of the minerals, quartz seems to be one of the most probable to take part in such processes. However, an external source of energy is needed, e.g. electric discharge. A device simulating the proposed conditions was designed and was used to simulate prebiotic conditions. Investigation of processes occurring during the stimulation of quartz with electric discharge was studied by means of Ultraviolet-visible (UV-VIS) spectroscopy, in order to monitor the generation kinetics of free radicals. Additionally, infrared spectroscopy was applied to identify chemical reaction products created in a solution of alanine or glycine, in the presence of quartz treated with electric discharge. Formation of increased amounts of free radicals, compared to experiments performed without quartz and/or amino acid, is reported, along with identification of possible degradation products of alanine. No synthetic reactions were observed.

  2. Characterization of psychrophilic alanine racemase from Bacillus psychrosaccharolyticus.

    PubMed

    Okubo, Y; Yokoigawa, K; Esaki, N; Soda, K; Kawai, H

    1999-03-16

    A psychrophilic alanine racemase gene from Bacillus psychrosaccharolyticus was cloned and expressed in Escherichia coli SOLR with a plasmid pYOK3. The gene starting with the unusual initiation codon GTG showed higher preference for codons ending in A or T. The enzyme purified to homogeneity showed the high catalytic activity even at 0 degrees C and was extremely labile over 35 degrees C. The enzyme was found to have a markedly large Km value (5.0 microM) for the pyridoxal 5'-phosphate (PLP) cofactor in comparison with other reported alanine racemases, and was stabilized up to 50 degrees C in the presence of excess amounts of PLP. The low affinity of the enzyme for PLP may be related to the thermolability, and may be related to the high catalytic activity, initiated by the transaldimination reaction, at low temperature. The enzyme has a distinguishing hydrophilic region around the residue no. 150 in the deduced amino acid sequence (383 residues), whereas the corresponding regions of other Bacillus alanine racemases are hydrophobic. The position of the region in the three dimensional structure of C atoms of the enzyme was predicted to be in a surface loop surrounding the active site. The region may interact with solvent and reduce the compactness of the active site. PMID:10080917

  3. ESR/alanine dosimetry applied to radiation processing

    NASA Astrophysics Data System (ADS)

    Mosse, D. C.

    The radiation processing of food products is specified in terms of absorbed dose, and processing quality is assessed on the basis of absorbed dose measurements. The validity of process quality control is highly dependent on the quality of the measurements and associated instrumentation; in this respect, dosimetry calibration by an Organization with official status provides an essential guarantee of validity to the quality control steps taken. The Laboratoire de Métrologie des Rayonnements Ionisants (L.M.R.I.) is the primary standards and evaluation laboratory approved by the Bureau National de Métrologie (B.N.M.), which is the French National Bureau of Standards. The LMRI implements correlation procedures in response to the various requirements which arise in connection with high doses and doserates. Such procedures are mainly based on ESR/alanine spectrometry, a dosimetry technique ideally suited to that purpose. Dosemeter geometry and design are tailored to operating conditions. "Photon" dosemeters consist of a detector material in powder or compacted form, and a wall with thickness and chemical composition consistent with the application. "Electron" dosemeters have a detector core of compacted alanine with thickness down to a few tenths of a millimeter. The ESR/alanine dosimetry technique, developed at LMRI is a flexible, reliable and accurate tool which effectively meets the various requirements arising in the field of reference dosimetry, where high doses and doserates are involved.

  4. Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion.

    PubMed

    Sousa, Cristovão M; Biancur, Douglas E; Wang, Xiaoxu; Halbrook, Christopher J; Sherman, Mara H; Zhang, Li; Kremer, Daniel; Hwang, Rosa F; Witkiewicz, Agnes K; Ying, Haoqiang; Asara, John M; Evans, Ronald M; Cantley, Lewis C; Lyssiotis, Costas A; Kimmelman, Alec C

    2016-08-25

    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by an intense fibrotic stromal response and deregulated metabolism. The role of the stroma in PDAC biology is complex and it has been shown to play critical roles that differ depending on the biological context. The stromal reaction also impairs the vasculature, leading to a highly hypoxic, nutrient-poor environment. As such, these tumours must alter how they capture and use nutrients to support their metabolic needs. Here we show that stroma-associated pancreatic stellate cells (PSCs) are critical for PDAC metabolism through the secretion of non-essential amino acids (NEAA). Specifically, we uncover a previously undescribed role for alanine, which outcompetes glucose and glutamine-derived carbon in PDAC to fuel the tricarboxylic acid (TCA) cycle, and thus NEAA and lipid biosynthesis. This shift in fuel source decreases the tumour’s dependence on glucose and serum-derived nutrients, which are limited in the pancreatic tumour microenvironment. Moreover, we demonstrate that alanine secretion by PSCs is dependent on PSC autophagy, a process that is stimulated by cancer cells. Thus, our results demonstrate a novel metabolic interaction between PSCs and cancer cells, in which PSC-derived alanine acts as an alternative carbon source. This finding highlights a previously unappreciated metabolic network within pancreatic tumours in which diverse fuel sources are used to promote growth in an austere tumour microenvironment. PMID:27509858

  5. Best Prediction of Yields for Long Lactations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactation records of any length now can be processed with the selection index methods known as best prediction (BP). Previous programs were limited to the 305-day standard used since 1935. Best prediction was implemented in 1998 to calculate lactation records in USDA genetic evaluations, replacing t...

  6. Lactation associated with herpes zoster pectoralis.

    PubMed

    Bhattacharya, S K; Girgla, H S

    1976-05-01

    The phenomenon of lactation associated with herpes zoster is unexpected. To our knowledge such an association has been reported only once. A case is reported in whom spontaneous lactation occurred in the ipsilateral breast following herpes zoster. It is believed to have resulted from stimulation of the intercostal nerve endings supplying the overlying skin of the breast. PMID:945354

  7. 21 CFR 184.1768 - Sodium lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1768 Sodium lactate. (a) Sodium lactate (C3H5O3Na, CAS Reg. No. 72-17-3) is the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid with sodium hydroxide. (b)...

  8. Synthesis and sweetness characteristics of L-aspartyl-D-alanine fenchyl esters.

    PubMed

    Yuasa, Y; Nagakura, A; Tsuruta, H

    2001-10-01

    Four isomers of the L-aspartyl-D-alanine fenchyl esters were prepared as potential peptide sweeteners. L-Aspartyl-D-alanine (+)-alpha-fenchyl ester and L-aspartyl-D-alanine (-)-beta-fenchyl ester showed sweetness with potencies 250 and 160 times higher than that of sucrose, respectively. In contrast, L-aspartyl-D-alanine (+)-beta-fenchyl ester and L-aspartyl-D-alanine (-)-alpha-fenchyl ester had the highest sweetness potencies at 5700 and 1100 times that of sucrose, respectively. In particular, L-aspartyl-D-alanine (-)-alpha-fenchyl ester had an excellent sweetness quality; but L-aspartyl-D-alanine (+)-beta-fenchyl ester did not have an excellent quality of sweetness because it displayed an aftertaste caused by the strong sweetness. PMID:11600060

  9. Short communication: Amino acid supplementation and stage of lactation alter apparent utilization of nutrients by blood neutrophils from lactating dairy cows in vitro.

    PubMed

    Garcia, M; Elsasser, T H; Juengst, L; Qu, Y; Bequette, B J; Moyes, K M

    2016-05-01

    Glutamine is the preferred AA used by polymorphonuclear leukocytes (PMN) during the inflammatory response. However, the effect of other AA on bovine PMN response during inflammation and how this is altered by stage of lactation has not been fully elucidated. The objective of this study was to determine the effect of additional AA supplementation (pool of AA excluding Gln) on AA profiles, gene expression, and inflammatory function of PMN from dairy cows in early and mid lactation in vitro. We used 18 Holstein cows for this study. Polymorphonuclear leukocytes were isolated. Working solutions of AA (0 or 4 mM) and LPS (0 or 50μg/mL) were added to cell populations suspended in RPMI and incubated for 2h at 37°C. We used a subset of samples for gene and protein expression. Concentrations of AA in medium were determined using gas chromatography-mass spectrometry with norleucine as an internal standard. Apparent AA and glucose utilization were calculated by subtracting the concentration after from that of before incubation. Data were analyzed as a randomized block design. Challenge with LPS increased the expression of proinflammatory genes and AA supplementation decreased both the expression of some proinflammatory genes and the media concentrations of tumor necrosis factor-α. Neither stage of lactation, LPS challenge, nor AA supplementation altered the chemotactic or phagocytic abilities of PMN in vitro. Polymorphonuclear leukocytes supplemented with AA had greater concentrations and apparent utilization of most of the supplemented AA, whereas the unsupplemented group had greater apparent utilization of glucose. Alanine was not provided in the media but was present in spent media, and Ile, Gly, and Pro were greater in spent media than in media before incubation indicating synthesis of these AA. Regarding expression of genes involved in nutrient metabolism, the expression of G6PD, coding for the enzyme glucose 6-phosphate dehydrogenase, was increased and that of PDHA1

  10. Brain lactate kinetics: Modeling evidence for neuronal lactate uptake upon activation.

    PubMed

    Aubert, Agnès; Costalat, Robert; Magistretti, Pierre J; Pellerin, Luc

    2005-11-01

    A critical issue in brain energy metabolism is whether lactate produced within the brain by astrocytes is taken up and metabolized by neurons upon activation. Although there is ample evidence that neurons can efficiently use lactate as an energy substrate, at least in vitro, few experimental data exist to indicate that it is indeed the case in vivo. To address this question, we used a modeling approach to determine which mechanisms are necessary to explain typical brain lactate kinetics observed upon activation. On the basis of a previously validated model that takes into account the compartmentalization of energy metabolism, we developed a mathematical model of brain lactate kinetics, which was applied to published data describing the changes in extracellular lactate levels upon activation. Results show that the initial dip in the extracellular lactate concentration observed at the onset of stimulation can only be satisfactorily explained by a rapid uptake within an intraparenchymal cellular compartment. In contrast, neither blood flow increase, nor extracellular pH variation can be major causes of the lactate initial dip, whereas tissue lactate diffusion only tends to reduce its amplitude. The kinetic properties of monocarboxylate transporter isoforms strongly suggest that neurons represent the most likely compartment for activation-induced lactate uptake and that neuronal lactate utilization occurring early after activation onset is responsible for the initial dip in brain lactate levels observed in both animals and humans. PMID:16260743

  11. Mice lacking ornithine-delta-aminotransferase have paradoxical neonatal hypoornithinaemia and retinal degeneration.

    PubMed

    Wang, T; Lawler, A M; Steel, G; Sipila, I; Milam, A H; Valle, D

    1995-10-01

    Deficiency of ornithine-delta-aminotransferase (OAT) in humans causes hyperornithinaemia and gyrate atrophy (GA), a blinding chorioretinal degeneration. Surprisingly, OAT-deficient mice produced by gene targeting exhibit neonatal hypoornithinaemia and lethality, rescuable by short-term arginine supplementation. Post-weaning, these mice develop hyperornithinaemia similar to human GA patients. Subsequent studies in one human GA infant also showed transient hypoornithinaemia. Thus, the OAT reaction plays opposite roles in neonatal and adult mammals. Over several months, OAT-deficient mice develop a retinal degeneration with involvement of photoreceptors and pigment epithelium. OAT-deficient mice appear to be an excellent model of human GA. PMID:7550347

  12. Reactions catalyzed by purified L-glutamine: keto-scyllo-inositol aminotransferase, an enzyme required for biosynthesis of aminocyclitol antibiotics.

    PubMed Central

    Lucher, L A; Chen, Y M; Walker, J B

    1989-01-01

    Dialyzed extracts of the gentamicin producer Micromonospora purpurea catalyze reactions which represent transaminations proposed for 2-deoxystreptamine biosynthesis. To determine whether these transaminations were catalyzed by a single aminotransferase or by multiple enzymes, we purified and characterized an L-glutamine:keto-scyllo-inositol aminotransferase from M. purpurea. This enzyme was purified 130- to 150-fold from late-log-phase mycelia of both wild-type M. purpurea and a 2-deoxystreptamine-less idiotroph. The cofactor pyridoxal phosphate was found to be tightly bound to the enzyme, and spectral analysis demonstrated its participation in the transamination reactions of this enzyme. The major physiological amino donor for the enzyme appears to be L-glutamine; the keto acid product derived from glutamine was characterized as 2-ketoglutaramate, indicating that the alpha amino group of glutamine participates in the transamination. We found that crude extracts contained omega-amidase activity, which may render transaminations with glutamine irreversible in vivo. The substrate specificity of the aminotransferase was shown to be restricted to deoxycyclitols, monoaminocyclitols, and diaminocyclitols, glutamine, and 2-ketoglutaramate, which contrasts with the broader substrate specificity of mammalian glutamine aminotransferase. The appearance of the enzyme in late-log phase, coupled with its narrow substrate specificity, indicates that it participates predominantly in 2-deoxystreptamine biosynthesis rather than in general metabolism. The enzyme catalyzes reactions which represent both transamination steps of 2-deoxystreptamine biosynthesis. Although copurification of two aminotransferases cannot be ruled out, our data are consistent with the participation of a single aminotransferase in the formation of both amino groups of 2-deoxystreptamine during biosynthesis by M. purpurea. We propose that this aminotransferase participates in a key initial step in the

  13. Current trends in lactate metabolism: introduction.

    PubMed

    Gladden, L Bruce

    2008-03-01

    In September 2006, at the Integrative Physiology of Exercise meeting in Indianapolis, IN, a symposium entitled "Current Trends in Lactate Metabolism" was presented. This short paper introduces two papers from that symposium. The first paper by L. Bruce Gladden briefly summarizes key pieces of evidence that support the cell-to-cell lactate shuttle, a concept that is no longer an hypothesis but that, instead, is now an established theory that provides the context for discussions of whole body metabolism. Gladden also offers a critical appraisal of the intracellular lactate shuttle and evaluates an ongoing controversy relative to the role of lactate in acid-base balance. In the second paper, Hashimoto and Brooks provide their evidence in support of the intracellular lactate shuttle and a lactate oxidation complex in the inner mitochondrial membrane. They also postulate that lactate is a cell-signaling molecule, "lactormone," that can upregulate gene and protein expression. Both papers have been updated since their original presentations and represent the current state of knowledge. PMID:18379209

  14. Etiology and therapeutic approach to elevated lactate

    PubMed Central

    Andersen, Lars W.; Mackenhauer, Julie; Roberts, Jonathan C.; Berg, Katherine M.; Cocchi, Michael N.; Donnino, Michael W.

    2014-01-01

    Lactate levels are commonly evaluated in acutely ill patients. Although most commonly used in the context of evaluating shock, lactate can be elevated for many reasons. While tissue hypoperfusion is probably the most common cause of elevation, many other etiologies or contributing factors exist. Clinicians need to be aware of the many potential causes of lactate elevation as the clinical and prognostic importance of an elevated lactate varies widely by disease state. Moreover, specific therapy may need to be tailored to the underlying cause of elevation. The current review is based on a comprehensive PubMed search and contains an overview of the pathophysiology of lactate elevation followed by an in-depth look at the varied etiologies, including medication-related causes. The strengths and weaknesses of lactate as a diagnostic/prognostic tool and its potential use as a clinical endpoint of resuscitation will be discussed. The review ends with some general recommendations on management of patients with elevated lactate. PMID:24079682

  15. Performance effects of acute β-alanine induced paresthesia in competitive cyclists.

    PubMed

    Bellinger, Phillip M; Minahan, Clare L

    2016-01-01

    β-alanine is a common ingredient in supplements consumed by athletes. Indeed, athletes may believe that the β-alanine induced paresthesia, experienced shortly after ingestion, is associated with its ergogenic effect despite no scientific mechanism supporting this notion. The present study examined changes in cycling performance under conditions of β-alanine induced paresthesia. Eight competitive cyclists (VO2max = 61.8 ± 4.2 mL·kg·min(-1)) performed three practices, one baseline and four experimental trials. The experimental trials comprised a 1-km cycling time trial under four conditions with varying information (i.e., athlete informed β-alanine or placebo) and supplement content (athlete received β-alanine or placebo) delivered to the cyclist: informed β-alanine/received β-alanine, informed placebo/received β-alanine, informed β-alanine/received placebo and informed placebo/received placebo. Questionnaires were undertaken exploring the cyclists' experience of the effects of the experimental conditions. A possibly likely increase in mean power was associated with conditions in which β-alanine was administered (±95% CL: 2.2% ± 4.0%), but these results were inconclusive for performance enhancement (p = 0.32, effect size = 0.18, smallest worthwhile change = 56% beneficial). A possibly harmful effect was observed when cyclists were correctly informed that they had ingested a placebo (-1.0% ± 1.9%). Questionnaire data suggested that β-alanine ingestion resulted in evident sensory side effects and six cyclists reported placebo effects. Acute ingestion of β-alanine is not associated with improved 1-km TT performance in competitive cyclists. These findings are in contrast to the athlete's "belief" as cyclists reported improved energy and the ability to sustain a higher power output under conditions of β-alanine induced paresthesia. PMID:25636080

  16. Lactate as a Biomarker for Sleep

    PubMed Central

    Naylor, Erik; Aillon, Daniel V.; Barrett, Brian S.; Wilson, George S.; Johnson, David A.; Johnson, Donna A.; Harmon, Hans P.; Gabbert, Seth; Petillo, Peter A.

    2012-01-01

    Study Objectives: An ideal biomarker for sleep should change rapidly with sleep onset, remain at a detectably differential level throughout the sleep period, and exhibit a rapid change with waking. Currently, no molecular marker has been identified that exhibits all three properties. This study examined three substances (lactate, glucose, and glutamate) for suitability as a sleep biomarker. Design: Using amperometric biosensor technology in conjunction with electroencephalograph (EEG) and electromyograph (EMG) monitoring, extracellular concentrations of lactate and glucose (Cohort 1) as well as lactate and glutamate (Cohort 2) were recorded over multiple sleep/wake cycles. Patients or Participants: There were 12 C57Bl/6J male mice (3-5 mo old). Interventions: Sleep and waking transitions were identified using EEG recordings. Extracellular concentrations of lactate, glucose, and glutamate were evaluated before and during transition events as well as during extended sleep and during a 6-h sleep deprivation period. Measurements and Results: Rapid and sustained increases in cortical lactate concentration (approximately 15 μM/min) were immediately observed upon waking and during rapid eye movement sleep. Elevated lactate concentration was also maintained throughout a 6-h period of continuous waking. A persistent and sustained decline in lactate concentration was measured during nonrapid eye movement sleep. Glutamate exhibited similar patterns, but with a much slower rise and decline (approximately 0.03 μM/min). Glucose concentration changes did not demonstrate a clear correlation with either sleep or wake. Conclusions: These findings indicate that extracellular lactate concentration is a reliable sleep/wake biomarker and can be used independently of the EEG signal. Citation: Naylor E; Aillon DV; Barrett BS; Wilson GS; Johnson DA; Johnson DA; Harmon HP; Gabbert S; Petillo PA. Lactate as a biomarker for sleep. SLEEP 2012;35(9):1209-1222. PMID:22942499

  17. Lactational mastitis caused by Streptococcus lactarius.

    PubMed

    Tena, Daniel; Fernández, Cristina; López-Garrido, Beatriz; Pérez-Balsalobre, Mercedes; Losa, Cristina; Medina-Pascual, María José; Sáez-Nieto, Juan Antonio

    2016-08-01

    Human infections caused by Streptococcus lactarius have not been previously reported. In the present report, we describe a lactational mastitis caused by this organism. The infection occurred in a 28-year-old breast-feeding female, with a 10-days history of moderate pain on the right breast. The patient was cured after antibiotic treatment with levofloxacin for 21 days. Our case shows that S. lactarius should be considered as a cause of lactational mastitis. The introduction of molecular microbiology techniques can be extremely useful for knowing the implication of streptococci in lactational mastitis. PMID:27220606

  18. Point mutations in the tyrosine aminotransferase gene in tyrosinemia type II.

    PubMed Central

    Natt, E; Kida, K; Odievre, M; Di Rocco, M; Scherer, G

    1992-01-01

    Tyrosinemia type II (Richner-Hanhart syndrome, RHS) is a disease of autosomal recessive inheritance characterized by keratitis, palmoplantar hyperkeratosis, mental retardation, and elevated blood tyrosine levels. The disease results from deficiency in hepatic tyrosine aminotransferase (TAT; L-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5), a 454-amino acid protein encoded by a gene with 12 exons. To identify the causative mutations in five TAT alleles cloned from three RHS patients, chimeric genes constructed from normal and mutant TAT alleles were tested in directing TAT activity in a transient expression assay. DNA sequence analysis of the regions identified as nonfunctional revealed six different point mutations. Three RHS alleles have nonsense mutations at codons 57, 223, and 417, respectively. One "complex" RHS allele carries a GT----GG splice donor mutation in intron 8 together with a Gly----Val substitution at amino acid 362. A new splice acceptor site in intron 2 of the fifth RHS allele leads to a shift in reading frame. Images PMID:1357662

  19. Biochemical and Structural Insights into the Aminotransferase CrmG in Caerulomycin Biosynthesis.

    PubMed

    Zhu, Yiguang; Xu, Jinxin; Mei, Xiangui; Feng, Zhan; Zhang, Liping; Zhang, Qingbo; Zhang, Guangtao; Zhu, Weiming; Liu, Jinsong; Zhang, Changsheng

    2016-04-15

    Caerulomycin A (CRM A 1) belongs to a family of natural products containing a 2,2'-bipyridyl ring core structure and is currently under development as a potent novel immunosuppressive agent. Herein, we report the functional characterization, kinetic analysis, substrate specificity, and structure insights of an aminotransferase CrmG in 1 biosynthesis. The aminotransferase CrmG was confirmed to catalyze a key transamination reaction to convert an aldehyde group to an amino group in the 1 biosynthetic pathway, preferring l-glutamate and l-glutamine as the amino donor substrates. The crystal structures of CrmG in complex with the cofactor 5'-pyridoxal phosphate (PLP) or 5'-pyridoxamine phosphate (PMP) or the acceptor substrate were determined to adopt a canonical fold-type I of PLP-dependent enzymes with a unique small additional domain. The structure guided site-directed mutagenesis identified key amino acid residues for substrate binding and catalytic activities, thus providing insights into the transamination mechanism of CrmG. PMID:26714051

  20. Structural Insight into the Mechanism of Substrate Specificity of Aedes Kynurenine Aminotransferase

    SciTech Connect

    Han,Q.; Gao, Y.; Robinson, H.; Li, J.

    2008-01-01

    Aedes aegypti kynurenine aminotransferase (AeKAT) is a multifunctional aminotransferase. It catalyzes the transamination of a number of amino acids and uses many biologically relevant a-keto acids as amino group acceptors. AeKAT also is a cysteine S-conjugate {beta}-lyase. The most important function of AeKAT is the biosynthesis of kynurenic acid, a natural antagonist of NMDA and {alpha}7-nicotinic acetylcholine receptors. Here, we report the crystal structures of AeKAT in complex with its best amino acid substrates, glutamine and cysteine. Glutamine is found in both subunits of the biological dimer, and cysteine is found in one of the two subunits. Both substrates form external aldemines with pyridoxal 5-phosphate in the structures. This is the first instance in which one pyridoxal 5-phosphate enzyme has been crystallized with cysteine or glutamine forming external aldimine complexes, cysteinyl aldimine and glutaminyl aldimine. All the units with substrate are in the closed conformation form, and the unit without substrate is in the open form, which suggests that the binding of substrate induces the conformation change of AeKAT. By comparing the active site residues of the AeKAT-cysteine structure with those of the human KAT I-phenylalanine structure, we determined that Tyr286 in AeKAT is changed to Phe278 in human KAT I, which may explain why AeKAT transaminates hydrophilic amino acids more efficiently than human KAT I does.

  1. Amino acid sequence of Salmonella typhimurium branched-chain amino acid aminotransferase.

    PubMed

    Feild, M J; Nguyen, D C; Armstrong, F B

    1989-06-13

    The complete amino acid sequence of the subunit of branched-chain amino acid aminotransferase (transaminase B, EC 2.6.1.42) of Salmonella typhimurium was determined. An Escherichia coli recombinant containing the ilvGEDAY gene cluster of Salmonella was used as the source of the hexameric enzyme. The peptide fragments used for sequencing were generated by treatment with trypsin, Staphylococcus aureus V8 protease, endoproteinase Lys-C, and cyanogen bromide. The enzyme subunit contains 308 residues and has a molecular weight of 33,920. To determine the coenzyme-binding site, the pyridoxal 5-phosphate containing enzyme was treated with tritiated sodium borohydride prior to trypsin digestion. Peptide map comparisons with an apoenzyme tryptic digest and monitoring radioactivity incorporation allowed identification of the pyridoxylated peptide, which was then isolated and sequenced. The coenzyme-binding site is the lysyl residue at position 159. The amino acid sequence of Salmonella transaminase B is 97.4% identical with that of Escherichia coli, differing in only eight amino acid positions. Sequence comparisons of transaminase B to other known aminotransferase sequences revealed limited sequence similarity (24-33%) when conserved amino acid substitutions are allowed and alignments were forced to occur on the coenzyme-binding site. PMID:2669973

  2. Prodynorphine opioid peptides and aspartate aminotransferase studied in spinal cord and sensory neurons

    SciTech Connect

    Sweetnam, P.M.

    1985-01-01

    An objective of this research was to obtain evidence for the synthesis and release of newly discovered opioid peptides, such as dynorphin, in spinal cord and sensory neurons. Several specific antisera were used to visualize dynorphin and related peptides in spinal cord and dorsal root ganglion neurons in dissociated cell culture. Antisera specific for the midportion of the dynorphin molecule revealed a subpopulation of spinal cord neurons with dense immunoreactive dynorphin in cell perikarya, but none in their associated neurites. Antisera specific for either the amino or carboxy terminal sequences of the molecule produced intense immunoreactivity in both cell perikarya and neurites of spinal neurons. These data suggest the cleavage products of dynorphin and not the complete molecule are possible neurotransmitters in the spinal cord. Additional evidence in support of this hypothesis was derived from radioimmunoassays of these cells and their culture medium following depolarization induced by elevated extracellular potassium. Antisera against aspartate aminotransferase revealed no differentially elevated immunoreactive aspartate aminotransferase in tissue sections of spinal cord or dorsal root ganglia.

  3. Caffeine–N-phthaloyl-β-alanine (1/1)

    PubMed Central

    Bhatti, Moazzam H.; Yunus, Uzma; Shah, Syed Raza; Flörke, Ulrich

    2012-01-01

    The title co-crystal [systematic name: 3-(1,3-dioxoisoindolin-2-yl)propanoic acid–1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione (1/1)], C8H10N4O2·C11H9NO4, is the combination of 1:1 adduct of N-phthaloyl-β-alanine with caffeine. The phthalimide and purine rings in the N-phthaloyl-β-alanine and caffeine mol­ecules are essentially planar, with r.m.s. deviations of the fitted atoms of 0.0078 and 0.0118 Å, respectively. In the crystal, the two mol­ecules are linked via an O—H⋯N hydrogen bond involving the intact carb­oxy­lic acid (COOH) group. The crystal structure is consolidated by C—H⋯O inter­actions. The H atoms of a methyl group of the caffeine mol­ecule are disordered over two sets of sites of equal occupancy. PMID:22719646

  4. The effect of immunonutrition (glutamine, alanine) on fracture healing

    PubMed Central

    Küçükalp, Abdullah; Durak, Kemal; Bayyurt, Sarp; Sönmez, Gürsel; Bilgen, Muhammed S.

    2014-01-01

    Background There have been various studies related to fracture healing. Glutamine is an amino acid with an important role in many cell and organ functions. This study aimed to make a clinical, radiological, and histopathological evaluation of the effects of glutamine on fracture healing. Methods Twenty rabbits were randomly allocated into two groups of control and immunonutrition. A fracture of the fibula was made to the right hind leg. All rabbits received standard food and water. From post-operative first day for 30 days, the study group received an additional 2 ml/kg/day 20% L-alanine L-glutamine solution via a gastric catheter, and the control group received 2 ml/kg/day isotonic via gastric catheter. At the end of 30 days, the rabbits were sacrificed and the fractures were examined clinically, radiologically, and histopathologically in respect to the degree of union. Results Radiological evaluation of the control group determined a mean score of 2.5 according to the orthopaedists and 2.65 according to the radiologists. In the clinical evaluation, the mean score was 1.875 for the control group and 2.0 for the study group. Histopathological evaluation determined a mean score of 8.5 for the control group and 9.0 for the study group. Conclusion One month after orally administered glutamine–alanine, positive effects were observed on fracture healing radiologically, clinically, and histopathologically, although no statistically significant difference was determined.

  5. Safety of dermatologic medications in pregnancy and lactation: Part II. Lactation.

    PubMed

    Butler, Daniel C; Heller, Misha M; Murase, Jenny E

    2014-03-01

    Dermatologists are frequently faced with questions from women who are breastfeeding about the safety of commonly prescribed topical and systemic medications during lactation. Safety data in lactation, particularly regarding medications that are unique to dermatology, are limited and can be difficult to locate. We have consolidated the available safety data in a single reference guide for clinicians. We review literature pertaining to the safety of common dermatologic therapies in lactation and offer recommendations based on the available evidence. PMID:24528912

  6. Genetics Home Reference: lactate dehydrogenase deficiency

    MedlinePlus

    ... dehydrogenase-B pieces (subunits) of the lactate dehydrogenase enzyme. This enzyme is found throughout the body and is important ... cells. There are five different forms of this enzyme, each made up of four protein subunits. Various ...

  7. Phyllodes Tumor in a Lactating Breast

    PubMed Central

    Murthy, Sudha S.; Raju, K. V. V. N.; Nair, Haripreetha G.

    2016-01-01

    Phyllodes tumor is attributed to a small fraction of primary tumors of the breast. Such tumors occur rarely in pregnancy and lactation. We report a case of a 25-year-old lactating mother presenting with a lump in the left breast. Core needle biopsy was opined as phyllodes tumor with lactational changes, and subsequent wide local excision confirmed the diagnosis of benign phyllodes tumor with lactational changes. The characteristic gross and microscopic findings of a well-circumscribed lesion with leaf-like fibroepithelial growth pattern and typical nonuniform or diffuse stromal proliferation with periductal accentuation even in the absence of mitotic figures can help clinch the diagnosis. Benign phyllodes is known for its recurrence and requires wide excision and close follow-up. It is vital to identify these lesions even on limited biopsies as therapeutic options differ. This case is presented for its rarity and the diagnostic challenge it poses in limited biopsy. PMID:27081326

  8. Phyllodes Tumor in a Lactating Breast.

    PubMed

    Murthy, Sudha S; Raju, K V V N; Nair, Haripreetha G

    2016-01-01

    Phyllodes tumor is attributed to a small fraction of primary tumors of the breast. Such tumors occur rarely in pregnancy and lactation. We report a case of a 25-year-old lactating mother presenting with a lump in the left breast. Core needle biopsy was opined as phyllodes tumor with lactational changes, and subsequent wide local excision confirmed the diagnosis of benign phyllodes tumor with lactational changes. The characteristic gross and microscopic findings of a well-circumscribed lesion with leaf-like fibroepithelial growth pattern and typical nonuniform or diffuse stromal proliferation with periductal accentuation even in the absence of mitotic figures can help clinch the diagnosis. Benign phyllodes is known for its recurrence and requires wide excision and close follow-up. It is vital to identify these lesions even on limited biopsies as therapeutic options differ. This case is presented for its rarity and the diagnostic challenge it poses in limited biopsy. PMID:27081326

  9. Regulation of bone mineral loss during lactation

    NASA Technical Reports Server (NTRS)

    Brommage, R.; Deluca, H. F.

    1985-01-01

    The effects of varyng dietary calcium and phosphorous levels, vitamin D deficiency, oophorectomy, adrenalectomy, and simultaneous pregnancy on bone mineral loss during lactation in rats are studied. The experimental procedures and evaluations are described. The femur ash weight of lactating and nonlactating rats are calculated. The data reveals that a decrease in dietary calcium of 0.02 percent results in an increased loss of bone mineral, an increase in calcium to 1.4 percent does not lessen bone mineral loss, and bone mineral loss in vitamin D deficient rats is independent of calcium levels. It is observed that changes in dietary phosphorous level, oophorectomy, adrenalectomy, and simultaneous pragnancy do not reduce bone mineral loss during lactation. The analysis of various hormones to determine the mechanism that triggers bone mineral loss during lactation is presented.

  10. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  11. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  12. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  13. Efficiency of Energy Utilization by Lactating Alpine Goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-six lactating Alpine does (50.5 ± 1.2 kg BW) were used to determine the effect of stage of lactation on energy utilization. Twelve does were assigned for measurement periods in early, mid-, and late lactation (28-35, 91-98, and 189 to 196 d of lactation). For six does of each group, after m...

  14. Maternal transfer of the cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) via milk to suckling offspring.

    PubMed

    Andersson, Marie; Karlsson, Oskar; Bergström, Ulrika; Brittebo, Eva B; Brandt, Ingvar

    2013-01-01

    The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been implicated in the etiology of neurodegenerative disease and proposed to be biomagnified in terrestrial and aquatic food chains. We have previously shown that the neonatal period in rats, which in humans corresponds to the last trimester of pregnancy and the first few years of age, is a particularly sensitive period for exposure to BMAA. The present study aimed to examine the secretion of (14)C-labeled L- and D-BMAA into milk in lactating mice and the subsequent transfer of BMAA into the developing brain. The results suggest that secretion into milk is an important elimination pathway of BMAA in lactating mothers and an efficient exposure route predominantly for L-BMAA but also for D-BMAA in suckling mice. Following secretion of [(14)C]L-BMAA into milk, the levels of [(14)C]L-BMAA in the brains of the suckling neonatal mice significantly exceeded the levels in the maternal brains. In vitro studies using the mouse mammary epithelial HC11 cell line confirmed a more efficient influx and efflux of L-BMAA than of D-BMAA in cells, suggesting enantiomer-selective transport. Competition experiments with other amino acids and a low sodium dependency of the influx suggests that the amino acid transporters LAT1 and LAT2 are involved in the transport of L-BMAA into milk. Given the persistent neurodevelopmental toxicity following injection of L-BMAA to neonatal rodent pups, the current results highlight the need to determine whether BMAA is enriched mother's and cow's milk. PMID:24194910

  15. Maternal Transfer of the Cyanobacterial Neurotoxin β-N-Methylamino-L-Alanine (BMAA) via Milk to Suckling Offspring

    PubMed Central

    Andersson, Marie; Karlsson, Oskar; Bergström, Ulrika; Brittebo, Eva B.; Brandt, Ingvar

    2013-01-01

    The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been implicated in the etiology of neurodegenerative disease and proposed to be biomagnified in terrestrial and aquatic food chains. We have previously shown that the neonatal period in rats, which in humans corresponds to the last trimester of pregnancy and the first few years of age, is a particularly sensitive period for exposure to BMAA. The present study aimed to examine the secretion of 14C-labeled L- and D-BMAA into milk in lactating mice and the subsequent transfer of BMAA into the developing brain. The results suggest that secretion into milk is an important elimination pathway of BMAA in lactating mothers and an efficient exposure route predominantly for L-BMAA but also for D-BMAA in suckling mice. Following secretion of [14C]L-BMAA into milk, the levels of [14C]L-BMAA in the brains of the suckling neonatal mice significantly exceeded the levels in the maternal brains. In vitro studies using the mouse mammary epithelial HC11 cell line confirmed a more efficient influx and efflux of L-BMAA than of D-BMAA in cells, suggesting enantiomer-selective transport. Competition experiments with other amino acids and a low sodium dependency of the influx suggests that the amino acid transporters LAT1 and LAT2 are involved in the transport of L-BMAA into milk. Given the persistent neurodevelopmental toxicity following injection of L-BMAA to neonatal rodent pups, the current results highlight the need to determine whether BMAA is enriched mother's and cow's milk. PMID:24194910

  16. Effect of β-alanine supplementation on high-intensity exercise performance.

    PubMed

    Harris, Roger C; Stellingwerff, Trent

    2013-01-01

    Carnosine is a dipeptide of β-alanine and L-histidine found in high concentrations in skeletal muscle. Combined with β-alanine, the pKa of the histidine imidazole ring is raised to ∼6.8, placing it within the muscle intracellular pH high-intensity exercise transit range. Combination with β-alanine renders the dipeptide inert to intracellular enzymic hydrolysis and blocks the histidinyl residue from participation in proteogenesis, thus making it an ideal, stable intracellular buffer. For vegetarians, synthesis is limited by β-alanine availability; for meat-eaters, hepatic synthesis is supplemented with β-alanine from the hydrolysis of dietary carnosine. Direct oral β-alanine supplementation will compensate for low meat and fish intake, significantly raising the muscle carnosine concentration. This is best achieved with a sustained-release formulation of β-alanine to avoid paresthesia symptoms and decreasing urinary spillover. In humans, increased levels of carnosine through β-alanine supplementation have been shown to increase exercise capacity and performance of several types, particularly where the high-intensity exercise range is 1-4 min. β-Alanine supplementation is used by athletes competing in high-intensity track and field cycling, rowing, swimming events and other competitions. PMID:23899755

  17. Lactation: historical patterns and potential for manipulation.

    PubMed

    Blackburn, D G

    1993-10-01

    The advent of biotechnology has made data on undomesticated mammals relevant to dairy science. Such data indicate the potential of lactation for modification, reveal genetic material available for use through bioengineering, help distinguish adaptive features from historical artifacts, and clarify limits on lactational diversity that date from early evolution. Evolutionary analysis indicates that a complex degree of lactation preceded divergence of the extant mammalian lineages during the Mesozoic Era. Although aspects of monotreme lactation appear to be ancestral for extant mammals, the marsupials and eutherians exhibit divergent specializations. Evidence is consistent with the idea that protolacteal glands evolved by combining features of skin gland populations into a new functional complex. Secretions of these ancestral glands may have had antimicrobial properties that protected the eggs or hatchlings and organic components that supplemented offspring nutrition. Following development of highly nutritious milks, evolution produced diversity in milk composition and function, milk output, length of lactation, mammary gland anatomy, and contributions of lactation to offspring nutrition. Certain marsupials are specialized in terms of functional independence and temporal plasticity of mammary tissues. Mammalian diversity indicates that artificial selection and physiological manipulation of domestic artiodactyls has only modestly exploited the potential of mammary glands as a nutritional source for humans. PMID:8227641

  18. Clinical use of lactate monitoring in critically ill patients

    PubMed Central

    2013-01-01

    Increased blood lactate levels (hyperlactataemia) are common in critically ill patients. Although frequently used to diagnose inadequate tissue oxygenation, other processes not related to tissue oxygenation may increase lactate levels. Especially in critically ill patients, increased glycolysis may be an important cause of hyperlactataemia. Nevertheless, the presence of increased lactate levels has important implications for the morbidity and mortality of the hyperlactataemic patients. Although the term lactic acidosis is frequently used, a significant relationship between lactate and pH only exists at higher lactate levels. The term lactate associated acidosis is therefore more appropriate. Two recent studies have underscored the importance of monitoring lactate levels and adjust treatment to the change in lactate levels in early resuscitation. As lactate levels can be measured rapidly at the bedside from various sources, structured lactate measurements should be incorporated in resuscitation protocols. PMID:23663301

  19. Radiolysis of alanine adsorbed in a clay mineral

    NASA Astrophysics Data System (ADS)

    Aguilar-Ovando, Ellen Y.; Negrón-Mendoza, Alicia

    2013-07-01

    Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically γ-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine.

  20. Radiolysis of alanine adsorbed in a clay mineral

    SciTech Connect

    Aguilar-Ovando, Ellen Y.; Negron-Mendoza, Alicia

    2013-07-03

    Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically {gamma}-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine.

  1. The Role of Glutamine Oxoglutarate Aminotransferase and Glutamate Dehydrogenase in Nitrogen Metabolism in Mycobacterium bovis BCG

    PubMed Central

    Viljoen, Albertus J.; Kirsten, Catriona J.; Baker, Bienyameen; van Helden, Paul D.; Wiid, Ian J. F.

    2013-01-01

    Recent evidence suggests that the regulation of intracellular glutamate levels could play an important role in the ability of pathogenic slow-growing mycobacteria to grow in vivo. However, little is known about the in vitro requirement for the enzymes which catalyse glutamate production and degradation in the slow-growing mycobacteria, namely; glutamine oxoglutarate aminotransferase (GOGAT) and glutamate dehydrogenase (GDH), respectively. We report that allelic replacement of the Mycobacterium bovis BCG gltBD-operon encoding for the large (gltB) and small (gltD) subunits of GOGAT with a hygromycin resistance cassette resulted in glutamate auxotrophy and that deletion of the GDH encoding-gene (gdh) led to a marked growth deficiency in the presence of L-glutamate as a sole nitrogen source as well as reduction in growth when cultured in an excess of L-asparagine. PMID:24367660

  2. Endurance exercise increases skeletal muscle kynurenine aminotransferases and plasma kynurenic acid in humans.

    PubMed

    Schlittler, Maja; Goiny, Michel; Agudelo, Leandro Z; Venckunas, Tomas; Brazaitis, Marius; Skurvydas, Albertas; Kamandulis, Sigitas; Ruas, Jorge L; Erhardt, Sophie; Westerblad, Håkan; Andersson, Daniel C

    2016-05-15

    Physical exercise has emerged as an alternative treatment for patients with depressive disorder. Recent animal studies show that exercise protects from depression by increased skeletal muscle kynurenine aminotransferase (KAT) expression which shifts the kynurenine metabolism away from the neurotoxic kynurenine (KYN) to the production of kynurenic acid (KYNA). In the present study, we investigated the effect of exercise on kynurenine metabolism in humans. KAT gene and protein expression was increased in the muscles of endurance-trained subjects compared with untrained subjects. Endurance exercise caused an increase in plasma KYNA within the first hour after exercise. In contrast, a bout of high-intensity eccentric exercise did not lead to increased plasma KYNA concentration. Our results show that regular endurance exercise causes adaptations in kynurenine metabolism which can have implications for exercise recommendations for patients with depressive disorder. PMID:27030575

  3. Activation of tyrosine aminotransferase expression in fetal liver by 5-azacytidine

    SciTech Connect

    Rothrock, R.; Perry, S.T.; Isham, K.R.; Lee, K.L.; Kenney, F.T.

    1983-06-15

    Rat fetuses of 20 days gestational age were treated in utero with the inhibitor of DNA methylation, 5-azacytidine. The liver enzyme tyrosine aminotransferase, normally expressed at very low levels until several hours after birth, was increased by the drug in the fetal livers after a lag period of about 9 hours, reaching a level 70-fold above control levels 18 hours after treatment. The high levels attained after 5-azacytidine treatment are comparable to those of glucocorticoid-treated adult livers, and were not further increased by administration of hydrocortisone to dams carrying treated fetuses. Cytidine and two other analogs, cytosine arabinoside and 6-azacytidine, were essentially without effect. 15 references, 2 figures, 1 table.

  4. Structurally Diverse Mitochondrial Branched Chain Aminotransferase (BCATm) Leads with Varying Binding Modes Identified by Fragment Screening.

    PubMed

    Borthwick, Jennifer A; Ancellin, Nicolas; Bertrand, Sophie M; Bingham, Ryan P; Carter, Paul S; Chung, Chun-Wa; Churcher, Ian; Dodic, Nerina; Fournier, Charlène; Francis, Peter L; Hobbs, Andrew; Jamieson, Craig; Pickett, Stephen D; Smith, Sarah E; Somers, Donald O'N; Spitzfaden, Claus; Suckling, Colin J; Young, Robert J

    2016-03-24

    Inhibitors of mitochondrial branched chain aminotransferase (BCATm), identified using fragment screening, are described. This was carried out using a combination of STD-NMR, thermal melt (Tm), and biochemical assays to identify compounds that bound to BCATm, which were subsequently progressed to X-ray crystallography, where a number of exemplars showed significant diversity in their binding modes. The hits identified were supplemented by searching and screening of additional analogues, which enabled the gathering of further X-ray data where the original hits had not produced liganded structures. The fragment hits were optimized using structure-based design, with some transfer of information between series, which enabled the identification of ligand efficient lead molecules with micromolar levels of inhibition, cellular activity, and good solubility. PMID:26938474

  5. Efficient L-Alanine Production by a Thermo-Regulated Switch in Escherichia coli.

    PubMed

    Zhou, Li; Deng, Can; Cui, Wen-Jing; Liu, Zhong-Mei; Zhou, Zhe-Min

    2016-01-01

    L-Alanine has important applications in food, pharmaceutical and veterinary and is used as a substrate for production of engineered thermoplastics. Microbial fermentation could reduce the production cost and promote the application of L-alanine. However, the presence of L-alanine significantly inhibit cell growth rate and cause a decrease in the ultimate L-alanine productivity. For efficient L-alanine production, a thermo-regulated genetic switch was designed to dynamically control the expression of L-alanine dehydrogenase (alaD) from Geobacillus stearothermophilus on the Escherichia coli B0016-060BC chromosome. The optimal cultivation conditions for the genetically switched alanine production using B0016-060BC were the following: an aerobic growth phase at 33 °C with a 1-h thermo-induction at 42 °C followed by an oxygen-limited phase at 42 °C. In a bioreactor experiment using the scaled-up conditions optimized in a shake flask, B0016-060BC accumulated 50.3 g biomass/100 g glucose during the aerobic growth phase and 96 g alanine/100 g glucose during the oxygen-limited phase, respectively. The L-alanine titer reached 120.8 g/l with higher overall and oxygen-limited volumetric productivities of 3.09 and 4.18 g/l h, respectively, using glucose as the sole carbon source. Efficient cell growth and L-alanine production were reached separately, by switching cultivation temperature. The results revealed the application of a thermo-regulated strategy for heterologous metabolic production and pointed to strategies for improving L-alanine production. PMID:26453031

  6. Contribution of cysteine aminotransferase and mercaptopyruvate sulfurtransferase to hydrogen sulfide production in peripheral neurons.

    PubMed

    Miyamoto, Ryo; Otsuguro, Ken-Ichi; Yamaguchi, Soichiro; Ito, Shigeo

    2014-07-01

    Hydrogen sulfide (H2 S) is a gaseous neuromodulator produced from L-cysteine. H2 S is generated by three distinct enzymatic pathways mediated by cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS), and mercaptopyruvate sulfurtransferase (MPST) coupled with cysteine aminotransferase (CAT). This study investigated the relative contributions of these three pathways to H2 S production in PC12 cells (rat pheochromocytoma-derived cells) and the rat dorsal root ganglion. CBS, CAT, and MPST, but not CSE, were expressed in the cells and tissues, and appreciable amounts of H2 S were produced from L-cysteine in the presence of α-ketoglutarate, together with dithiothreitol. The production of H2 S was inhibited by a CAT inhibitor (aminooxyacetic acid), competitive CAT substrates (L-aspartate and oxaloacetate), and RNA interference (RNAi) against MPST. Immunocytochemistry revealed a mitochondrial localization of MPST in PC12 cells and dorsal root ganglion neurons, and the amount of H2 S produced by CAT/MPST at pH 8.0, a physiological mitochondrial matrix pH, was comparable to that produced by CSE and CBS in the liver and the brain, respectively. Furthermore, H2 S production was markedly increased by alkalization. These results indicate that CAT and MPST are primarily responsible for H2 S production in peripheral neurons, and that the regulation of mitochondrial metabolism may influence neuronal H2 S generation. In the peripheral nervous system, hydrogen sulfide (H2 S) has been implicated in neurogenic pain or hyperalgesia. This study provides evidence that H2 S is synthesized in peripheral neurons through two mitochondrial enzymes, cysteine aminotransferase (CAT) and mercaptopyruvate sulfurtransferase (MPST). We propose that mitochondrial metabolism plays key roles in the physiology and pathophysiology of the peripheral nervous system via regulation of neuronal H2 S production. PMID:24611772

  7. Recombinant expression, purification and crystallographic studies of the mature form of human mitochondrial aspartate aminotransferase.

    PubMed

    Jiang, Xiuping; Wang, Jia; Chang, Haiyang; Zhou, Yong

    2016-02-01

    Mitochondrial aspartate aminotransferase (mAspAT) was recognized as a moonlighting enzyme because it has not only aminotransferase activity but also a high-affinity long-chain fatty acids (LCFA) binding site. This enzyme plays a key role in amino acid metabolism, biosynthesis of kynurenic acid and transport of the LCFA. Therefore, it is important to study the structure-function relationships of human mAspAT protein. In this work, the mature form of human mAspAT was expressed to a high level in Escherichia coli periplasmic space using pET-22b vector, purified by a combination of immobilized metal-affinity chromatography and cation exchange chromatography. Optimal activity of the enzyme occurred at a temperature of 47.5ºC and a pH of 8.5. Crystals of human mAspAT were grown using the hanging-drop vapour diffusion method at 277K with 0.1 M HEPES pH 6.8 and 25%(v/v) Jeffamine(®) ED-2001 pH 6.8. The crystals diffracted to 2.99 Å and belonged to the space group P1 with the unit-cell parameters a =56.7, b = 76.1, c = 94.2 Å, α =78.0, β =85.6, γ = 78.4º. Elucidation of mAspAT structure can provide a molecular basis towards understanding catalysis mechanism and substrate binding site of enzyme. PMID:26902786

  8. Histidine Degradation via an Aminotransferase Increases the Nutritional Flexibility of Candida glabrata

    PubMed Central

    Seider, Katja; Richter, Martin Ernst; Bremer-Streck, Sibylle; Ramachandra, Shruthi; Kiehntopf, Michael; Brock, Matthias

    2014-01-01

    The ability to acquire nutrients during infections is an important attribute in microbial pathogenesis. Amino acids are a valuable source of nitrogen if they can be degraded by the infecting organism. In this work, we analyzed histidine utilization in the fungal pathogen of humans Candida glabrata. Hemiascomycete fungi, like C. glabrata or Saccharomyces cerevisiae, possess no gene coding for a histidine ammonia-lyase, which catalyzes the first step of a major histidine degradation pathway in most other organisms. We show that C. glabrata instead initializes histidine degradation via the aromatic amino acid aminotransferase Aro8. Although ARO8 is also present in S. cerevisiae and is induced by extracellular histidine, the yeast cannot use histidine as its sole nitrogen source, possibly due to growth inhibition by a downstream degradation product. Furthermore, C. glabrata relies only on Aro8 for phenylalanine and tryptophan utilization, since ARO8, but not its homologue ARO9, was transcriptionally activated in the presence of these amino acids. Accordingly, an ARO9 deletion had no effect on growth with aromatic amino acids. In contrast, in S. cerevisiae, ARO9 is strongly induced by tryptophan and is known to support growth on aromatic amino acids. Differences in the genomic structure of the ARO9 gene between C. glabrata and S. cerevisiae indicate a possible disruption in the regulatory upstream region. Thus, we show that, in contrast to S. cerevisiae, C. glabrata has adapted to use histidine as a sole source of nitrogen and that the aromatic amino acid aminotransferase Aro8, but not Aro9, is the enzyme required for this process. PMID:24728193

  9. Glycolysis and the significance of lactate in traumatic brain injury

    PubMed Central

    Carpenter, Keri L. H.; Jalloh, Ibrahim; Hutchinson, Peter J.

    2015-01-01

    In traumatic brain injury (TBI) patients, elevation of the brain extracellular lactate concentration and the lactate/pyruvate ratio are well-recognized, and are associated statistically with unfavorable clinical outcome. Brain extracellular lactate was conventionally regarded as a waste product of glucose, when glucose is metabolized via glycolysis (Embden-Meyerhof-Parnas pathway) to pyruvate, followed by conversion to lactate by the action of lactate dehydrogenase, and export of lactate into the extracellular fluid. In TBI, glycolytic lactate is ascribed to hypoxia or mitochondrial dysfunction, although the precise nature of the latter is incompletely understood. Seemingly in contrast to lactate's association with unfavorable outcome is a growing body of evidence that lactate can be beneficial. The idea that the brain can utilize lactate by feeding into the tricarboxylic acid (TCA) cycle of neurons, first published two decades ago, has become known as the astrocyte-neuron lactate shuttle hypothesis. Direct evidence of brain utilization of lactate was first obtained 5 years ago in a cerebral microdialysis study in TBI patients, where administration of 13C-labeled lactate via the microdialysis catheter and simultaneous collection of the emerging microdialysates, with 13C NMR analysis, revealed 13C labeling in glutamine consistent with lactate utilization via the TCA cycle. This suggests that where neurons are too damaged to utilize the lactate produced from glucose by astrocytes, i.e., uncoupling of neuronal and glial metabolism, high extracellular levels of lactate would accumulate, explaining the association between high lactate and poor outcome. Recently, an intravenous exogenous lactate supplementation study in TBI patients revealed evidence for a beneficial effect judged by surrogate endpoints. Here we review the current state of knowledge about glycolysis and lactate in TBI, how it can be measured in patients, and whether it can be modulated to achieve better

  10. Voluntary exercise during pregnancy and lactation and its effect on lactational performance in mice.

    PubMed

    Karasawa, K; Suwa, J; Kimura, S

    1981-01-01

    The amount of voluntary exercise during pregnancy and lactation and its effect on the lactational performance in mice were investigated. Female mice were housed in exercise cages with treadwheels during periods of growth, pregnancy and lactation and the amounts of exercise were measured. It was observed that growing female mice exercised voluntarily at a level of approximately 5,000 rotations (diameter of treadwheel; 13.5 cm) per day during the 4-week growth period. After conception, the amount of exercise gradually decreased and in late pregnancy running activity decreased markedly. Throughout the lactational period dams exercised lightly. As indices of lactational performance, the body weights of pups nursed in litters of 8, milk yield and cellular development of abdominal-inguinal mammary glands were examined. There were no significant differences in the final body weights of pups, milk yield per day or development of mammary glands between exercise and non-exercise groups. PMID:7328442

  11. The cyanobacterial amino acid β-N-methylamino-l-alanine perturbs the intermediary metabolism in neonatal rats.

    PubMed

    Engskog, Mikael K R; Karlsson, Oskar; Haglöf, Jakob; Elmsjö, Albert; Brittebo, Eva; Arvidsson, Torbjörn; Pettersson, Curt

    2013-10-01

    The neurotoxic amino acid β-N-methylamino-l-alanine (BMAA) is produced by most cyanobacteria. BMAA is considered as a potential health threat because of its putative role in neurodegenerative diseases. We have previously observed cognitive disturbances and morphological brain changes in adult rodents exposed to BMAA during the development. The aim of this study was to characterize changes of major intermediary metabolites in serum following neonatal exposure to BMAA using a non-targeted metabolomic approach. NMR spectroscopy was used to obtain serum metabolic profiles from neonatal rats exposed to BMAA (40, 150, 460mg/kg) or vehicle on postnatal days 9-10. Multivariate data analysis of binned NMR data indicated metabolic pattern differences between the different treatment groups. In particular five metabolites, d-glucose, lactate, 3-hydroxybutyrate, creatine and acetate, were changed in serum of BMAA-treated neonatal rats. These metabolites are associated with changes in energy metabolism and amino acid metabolism. Further statistical analysis disclosed that all the identified serum metabolites in the lowest dose group were significantly (p<0.05) decreased. The neonatal rat model used in this study is so far the only animal model that displays significant biochemical and behavioral effects after a low short-term dose of BMAA. The demonstrated perturbation of intermediary metabolism may contribute to BMAA-induced developmental changes that result in long-term effects on adult brain function. PMID:23886855

  12. Determination of the anti-inflammatory and cytoprotective effects of l-glutamine and l-alanine, or dipeptide, supplementation in rats submitted to resistance exercise.

    PubMed

    Raizel, Raquel; Leite, Jaqueline Santos Moreira; Hypólito, Thaís Menezes; Coqueiro, Audrey Yule; Newsholme, Philip; Cruzat, Vinicius Fernandes; Tirapegui, Julio

    2016-08-01

    We evaluated the effects of chronic oral supplementation with l-glutamine and l-alanine in their free form or as the dipeptide l-alanyl-l-glutamine (DIP) on muscle damage, inflammation and cytoprotection, in rats submitted to progressive resistance exercise (RE). Wistar rats (n 8/group) were submitted to 8-week RE, which consisted of climbing a ladder with progressive loads. In the final 21 d before euthanasia, supplements were delivered in a 4 % solution in drinking water. Glutamine, creatine kinase (CK), lactate dehydrogenase (LDH), TNF-α, specific IL (IL-1β, IL-6 and IL-10) and monocyte chemoattractant protein-1 (MCP-1) levels were evaluated in plasma. The concentrations of glutamine, TNF-α, IL-6 and IL-10, as well as NF-κB activation, were determined in extensor digitorum longus (EDL) skeletal muscle. HSP70 level was assayed in EDL and peripheral blood mononuclear cells (PBMC). RE reduced glutamine concentration in plasma and EDL (P<0·05 v. sedentary group). However, l-glutamine supplements (l-alanine plus l-glutamine (GLN+ALA) and DIP groups) restored glutamine levels in plasma (by 40 and 58 %, respectively) and muscle (by 93 and 105 %, respectively). GLN+ALA and DIP groups also exhibited increased level of HSP70 in EDL and PBMC, consistent with the reduction of NF-κB p65 activation and cytokines in EDL. Muscle protection was also indicated by attenuation in plasma levels of CK, LDH, TNF-α and IL-1β, as well as an increase in IL-6, IL-10 and MCP-1. Our study demonstrates that chronic oral l-glutamine treatment (given with l-alanine or as dipeptide) following progressive RE induces cyprotective effects mediated by HSP70-associated responses to muscle damage and inflammation. PMID:27215379

  13. Inactivation of 3-(3,4-dihydroxyphenyl)alanine decarboxylase by 2-(fluoromethyl)-3-(3,4-dihydroxyphenyl)alanine.

    PubMed

    Maycock, A L; Aster, S D; Patchett, A A

    1980-02-19

    2-(Fluoromethyl)-3-(3,4-dihydroxyphenyl)alanine [alpha-FM-Dopa (I)] causes rapid, time-dependent, stereospecific, and irreversible inhibition of hog kidney aromatic amino acid (Dopa) decarboxylase. The inactivation occurs with loss of both the carboxyl carbon and fluoride from I and results in the stoichimetric formation of a covalent enzyme-inhibitor adduct. The data are consistent with I being a suicide inactivator of the enzyme, and a plausible mechanism for the inactivation process is presented. The inactivation is highly efficient in that there is essentially no enzymatic turnover of I to produce the corresponding amine, 1-(fluoromethyl)-2-(3,4-dihydroxyphenyl)ethylamine [alpha-FM-dopamine (II)]. Amine II is also a potent inactivator of the enzyme. In vivo compound I is found to inactivate both brain and peripheral (liver) Dopa decarboxylase activity. The possible significance of these data with respect to the known antihypertensive effect of I is discussed. PMID:7356954

  14. Catalytic properties of Sepharose-bound L-alanine dehydrogenase from Bacillus cereus.

    PubMed

    Mureşan, L; Vancea, D; Presecan, E; Porumb, H; Lascu, I; Oargă, M; Matinca, D; Abrudan, I; Bârzu, O

    1983-02-15

    (1) L-Alanine dehydrogenase from Bacillus cereus was purified by a two-step chromatographic procedure involving Cibacron-Blue 3G-A Sepharose 4B-CL, and Sepharose 6B-CL, and immobilized on CNBr-activated Sepharose 4B. (2) Following immobilization via two of the six subunits, L-alanine dehydrogenase retained 66% of the specific activity of the soluble enzyme. The affinity of the immobilized enzyme for NH4+, pyruvate and L-alanine, was not different to that of the soluble form. The Km of the Sepharose-bound L-alanine dehydrogenase for pyridine coenzymes was 6-8-times higher than in the soluble case. (3) The stability of L-alanine dehydrogenase towards urea or thermal denaturation was increased by immobilization. (4) The incubation at 37 degrees C for 24 h of the immobilized L-alanine dehydrogenase with 3 M NH4Cl/NH4OH buffer (pH 9) released 70% of the enzyme. The specific activity and the affinity of the 'solubilized' L-alanine dehydrogenase for the pyridine coenzymes was the same as that obtained with the original, soluble L-alanine dehydrogenase. PMID:6404304

  15. Polymerization of alanine in the presence of a non-swelling montmorillonite

    NASA Technical Reports Server (NTRS)

    Paecht-Horowitz, M.; Lahav, N.

    1977-01-01

    Alanine, starting from alanine-adenylate, has been polymerized in the presence of non-swelling Al-montmorillonite. The yield of polymerization is much lower than that obtained in the presence of swelling Na-montmorillonite. The possibility that the changing interlayer spacing in Na-montmorillonite might be responsible for its catalytic properties, is discussed.

  16. Initiation of Spore Germination in Bacillus subtilis: Relationship to Inhibition of l-Alanine Metabolism

    PubMed Central

    Prasad, Chandan

    1974-01-01

    The inhibitory effects of anthranilic acid esters (methyl anthranilate and N-methyl anthranilate) on the l-alanine-induced initiation of spore germination was examined in Bacillus subtilis 168. Methyl anthranilate irreversibly inhibited alanine initiation by a competitive mechanism. In its presence, the inhibition could be reversed only by the combined addition of d-glucose, d-fructose, and K+. Both l-alanine dehydrogenase and l-glutamate-pyruvate transaminase, enzymes which catalyze the first reaction in l-alanine metabolism, were competitively inhibited by methyl anthranilate. The Ki values for germination initiation (0.053 mM) and of l-glutamate-pyruvate transaminase (0.068 mM) were similar, whereas that for l-alanine dehydrogenase (0.4 mM) was six to seven times higher. Since a mutant lacking l-alanine dehydrogenase activity germinated normally in l-alanine alone, it is speculated that the major pathway of l-alanine metabolism during initiation may be via transmination reaction. PMID:4212093

  17. [Interference of ethylene glycol on lactate assays].

    PubMed

    Graïne, H; Toumi, K; Roullier, V; Capeau, J; Lefèvre, G

    2007-01-01

    Ethylene glycol is broken down to three main organic acids: glycolic acid, glyoxylic acid and oxalic acid which cause severe metabolic acidosis. Effect of these three acids on lactate assays was evaluated in five blood gas analysers and two clinical chemistry analysers. For all systems, no influence of oxalic acid on lactate results could be demonstrated. No interference of glycolic acid could be observed on lactate assay performed with Rapid Lab 1265 (R: 104,9 +/- 12,1%), Vitros 950 (R: 105,7 +/- 5,3 %) and Architect ci8200 (R: 104,9 +/- 4,7%), but on the contrary, CCX 4, OMNI S, ABL 725 and 825 demonstrated a concentration-dependent interference. No interference of glyoxylic acid could be observed with Vitros 950, but a positive interference could be observed with ABL 725 and 825, OMNI S, CCX4 and Architect ci8200 A linear relationship between apparent lactate concentration found with ABL 725 and 825, OMNI S, CCX 4, and glyoxylic acid could be observed (0,94 < r < 0,99), a weaker interference being observed with Rapid Lab 1265 and Architect ci 8200. Our results demonstrated that in case of ethylene glycol poisoning, cautious interpretation of lactate assay should be done, since wrong results of lactacidemia could lead to misdiagnostic and delay patient treatment. PMID:17627925

  18. A stereospecific solid-phase screening assay for colonies expressing both (R)- and (S)-selective ω-aminotransferases.

    PubMed

    Willies, Simon C; Galman, James L; Slabu, Iustina; Turner, Nicholas J

    2016-02-28

    A novel solid-phase screening assay was developed for colonies expressing both (R)- and (S)-selective ω-aminotransferases. This high-throughput assay can be used to screen rapidly large variant libraries with enhanced substrate selectivity and enantioselectivities. PMID:26755753

  19. Thermal decomposition behavior of potassium and sodium jarosite synthesized in the presence of methylamine and alanine

    SciTech Connect

    J. Michelle Kotler; Nancy W. Hinman; C. Doc Richardson; Jill R. Scott

    2010-10-01

    Biomolecules, methylamine and alanine, found associated with natural jarosite samples peaked the interest of astrobiologists and planetary geologists. How the biomolecules are associated with jarosite remains unclear although the mechanism could be important for detecting biosignatures in the rock record on Earth and other planets. A series of thermal gravimetric experiments using synthetic K-jarosite and Na-jarosite were conducted to determine if thermal analysis could differentiate physical mixtures of alanine and methylamine with jarosite from samples where the methylamine or alanine was incorporated into the synthesis procedure. Physical mixtures and synthetic experiments with methylamine and alanine could be differentiated from one another and from the standards by thermal analysis for both the K-jarosite and Na-jarosite end-member suites. Changes included shifts in on-set temperatures, total temperature changes from on-set to final, and the presence of indicator peaks for methylamine and alanine in the physical mixture experiments.

  20. How similar is the electronic structures of β-lactam and alanine?

    NASA Astrophysics Data System (ADS)

    Chatterjee, Subhojyoti; Ahmed, Marawan; Wang, Feng

    2016-02-01

    The C1s spectra of β-lactam i.e. 2-azetidinone (C3H5NO), a drug and L-alanine (C3H7NO2), an amino acid, exhibit striking similarities, which may be responsible for the competition between 2-azetidinone and the alanyl-alanine moiety in biochemistry. The present study is to reveal the degree of similarities and differences between their electronic structures of the two model molecular pairs. It is found that the similarities in C1s and inner valence binding energy spectra are due to their bonding connections but other properties such as ring structure (in 2-azetidinone) and chiral carbon (alanine) can be very different. Further, the inner valence region of ionization potential greater than 18 eV for 2-azetidinone and alanine is also significantly similar. Finally the strained lactam ring exhibits more chemical reactivity measured at all non-hydrogen atoms by Fukui functions with respect to alanine.

  1. Single sodium pyruvate ingestion modifies blood acid-base status and post-exercise lactate concentration in humans.

    PubMed

    Olek, Robert A; Kujach, Sylwester; Wnuk, Damian; Laskowski, Radoslaw

    2014-05-01

    This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg(-1) of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% VO2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM) than in the placebo trial (10.6 ± 0.3 mM, p < 0.05) and remained elevated (nonsignificant) after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise. PMID:24841105

  2. Single Sodium Pyruvate Ingestion Modifies Blood Acid-Base Status and Post-Exercise Lactate Concentration in Humans

    PubMed Central

    Olek, Robert A.; Kujach, Sylwester; Wnuk, Damian; Laskowski, Radoslaw

    2014-01-01

    This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg−1 of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% O2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM) than in the placebo trial (10.6 ± 0.3 mM, p < 0.05) and remained elevated (nonsignificant) after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise. PMID:24841105

  3. Expression, purification, and characterization of alanine racemase from Pseudomonas putida YZ-26.

    PubMed

    Liu, Jun-Lin; Liu, Xiao-Qin; Shi, Ya-Wei

    2012-01-01

    Alanine racemase catalyzes the interconversion of D: - and L: -alanine and plays an important role in supplying D: -alanine, a component of peptidoglycan biosynthesis, to most bacteria. Alanine racemase exists mostly in prokaryotes and is generally absent in higher eukaryotes; this makes it an attractive target for the design of new antibacterial drugs. Here, we present the cloning and characterization of a new gene-encoding alanine racemase from Pseudomonas putida YZ-26. An open reading frame (ORF) of 1,230 bp, encoding a protein of 410 amino acids with a calculated molecular weight of 44,217.3 Da, was cloned into modified vector pET32M to form the recombinant plasmid pET-alr. After introduction into E.coli BL21, the strain pET-alr/E.coli BL21 expressed His(6)-tagged alanine racemase. The recombinant alanine racemase was efficiently purified to homogeneity using Ni(2+)-NTA and a gel filtration column, with 82.5% activity recovery. The amino acid sequence deduced from the alanine racemase gene revealed identity similarities of 97.0, 93, 23, and 22.0% with from P. putida F1, P. putida200, P. aeruginosa, and Salmonella typhimurium, respectively. The recombinant alanine racemase is a monomeric protein with a molecular mass of 43 kDa. The enzyme exhibited activity with L: -alanine and L: -isoleucine, and showed higher specificity for the former compared with the latter. The enzyme was stable from pH 7.0-11.0; its optimum pH was at 9.0. The optimum temperature for the enzyme was 37°C, and its activity was rapidly lost at temperatures above 40°C. Divalent metals, including Sr(2+), Mn(2+), Co(2+), and Ni(2+) obviously enhanced enzymatic activity, while the Cu(2+) ion showed inhibitory effects. PMID:22806802

  4. Nonalcoholic Steatohepatitis and Hepatic Fibrosis in HIV-1–Monoinfected Adults With Elevated Aminotransferase Levels on Antiretroviral Therapy

    PubMed Central

    Morse, Caryn G.; McLaughlin, Mary; Matthews, Lindsay; Proschan, Michael; Thomas, Francine; Gharib, Ahmed M.; Abu-Asab, Mones; Orenstein, Abigail; Engle, Ronald E.; Hu, Xiaojun; Lempicki, Richard; Hadigan, Colleen; Kleiner, David E.; Heller, Theo; Kovacs, Joseph A.

    2015-01-01

    Background. Persistent aminotransferase elevations are common in human immunodeficiency virus (HIV)–infected patients on antiretroviral therapy (ART), including those without hepatitis B or C coinfection, but their clinical significance is unknown. Methods. HIV-infected adults with aminotransferase levels elevated above the upper limit of normal for ≥6 months while receiving ART, and without chronic viral hepatitis or other known causes of chronic liver disease, underwent a detailed metabolic assessment and liver biopsy. Results. Sixty-two HIV-infected subjects completed the study. Forty (65%) had clinically significant liver pathology, including 34 (55%) with nonalcoholic steatohepatitis (NASH) and 11 (18%) with bridging fibrosis, 10 of whom also had NASH. Nonspecific abnormalities alone were seen in 22 (35%) subjects, including mild steatosis, mild to moderate inflammation, and evidence of drug adaptation. Insulin resistance, obesity, and the presence of either of 2 minor alleles in the PNPLA3 gene were significantly associated with increased risk of NASH and fibrosis. NASH and/or fibrosis were not associated with duration of HIV infection or ART, specific antiretroviral drugs, history of opportunistic infection, immune status, or duration of aminotransferase elevation. Conclusions. HIV-infected adults with chronic aminotransferase elevations while receiving ART have a high rate of liver disease. Noninvasive testing can help identify liver disease in such patients, but liver biopsy is necessary to definitively identify those at risk for liver disease progression and complications. Longitudinal follow-up of this cohort will better characterize the natural history of aminotransferase elevations in this population and identify noninvasive biomarkers of liver disease progression. PMID:25681381

  5. [Relevance of lactate determination in sports medicine].

    PubMed

    Schwaberger, G; Pessenhofer, H; Schmid, P

    1985-05-31

    In the last years increasing attention has been paid to specific changes of muscle metabolism during physical exertion in the diagnosis of physical performance. Lactate resp. lactic acid, being the terminal product of anaerobic glycolysis, has gained a central position in that field of sports medicine. Measuring lactate concentration level in arterialized capillary blood (drawn from the earlobe) one can investigate both the onset of anaerobic-lactic energy production during increasing work load (aerobic-anaerobic transition) and the maximal amount of anaerobic energy formation during short periods of exhausting work. In this way, using suitable work load protocols, the aerobic capacity (endurance capacity) on the one hand and the anaerobic capacity on the other hand can be determined. Therefore the most prominent components of energy production in working muscle and physical performance in general are accessible by measurement of blood lactate concentration level. PMID:4036145

  6. Elevated Lactate Secondary to Gastrointestinal Beriberi.

    PubMed

    Duca, James; Lum, Corey J; Lo, Angela M

    2016-01-01

    Thiamine deficiency usually occurs with prolonged nutritional deficiency and is almost universally identified with Wernicke's encephalopathy or beriberi. It is also, however, a rare cause of elevated lactate and gastroenterological symptoms. This case report describes a 30-year-old man with 2 weeks of gastroenterological symptoms and intermittent oral intake, who was found to have an elevated lactate level. Neurological exam was normal and an extensive workup was negative, but after being treated with thiamine, his lactate level improved overnight and all of his symptoms resolved. Thiamine levels returned low at 44 nmol/L (normal 78-185 nmol/L). Lack of recognition of this phenomenon, while rare, can lead to unnecessary tests and procedures and increased morbidity and mortality. PMID:25876741

  7. Calibration of helical tomotherapy machine using EPR/alanine dosimetry

    SciTech Connect

    Perichon, Nicolas; Garcia, Tristan; Francois, Pascal; Lourenco, Valerie; Lesven, Caroline; Bordy, Jean-Marc

    2011-03-15

    Purpose: Current codes of practice for clinical reference dosimetry of high-energy photon beams in conventional radiotherapy recommend using a 10x10 cm{sup 2} square field, with the detector at a reference depth of 10 cm in water and 100 cm source to surface distance (SSD) (AAPM TG-51) or 100 cm source-to-axis distance (SAD) (IAEA TRS-398). However, the maximum field size of a helical tomotherapy (HT) machine is 40x5 cm{sup 2} defined at 85 cm SAD. These nonstandard conditions prevent a direct implementation of these protocols. The purpose of this study is twofold: To check the absorbed dose in water and dose rate calibration of a tomotherapy unit as well as the accuracy of the tomotherapy treatment planning system (TPS) calculations for a specific test case. Method: Both topics are based on the use of electron paramagnetic resonance (EPR) using alanine as transfer dosimeter between the Laboratoire National Henri Becquerel (LNHB) {sup 60}Co-{gamma}-ray reference beam and the Institut Curie's HT beam. Irradiations performed in the LNHB reference {sup 60}Co-{gamma}-ray beam allowed setting up the calibration method, which was then implemented and tested at the LNHB 6 MV linac x-ray beam, resulting in a deviation of 1.6% (at a 1% standard uncertainty) relative to the reference value determined with the standard IAEA TRS-398 protocol. Results: HT beam dose rate estimation shows a difference of 2% with the value stated by the manufacturer at a 2% standard uncertainty. A 4% deviation between measured dose and the calculation from the tomotherapy TPS was found. The latter was originated by an inadequate representation of the phantom CT-scan values and, consequently, mass densities within the phantom. This difference has been explained by the mass density values given by the CT-scan and used by the TPS which were not the true ones. Once corrected using Monte Carlo N-Particle simulations to validate the accuracy of this process, the difference between corrected TPS

  8. Metabolic Imaging: A link between Lactate Dehydrogenase A, Lactate and Tumor Phenotype

    PubMed Central

    Thakur, Sunitha B.; Vider, Jelena; Russell, James; Blasberg, Ronald; Koutcher, Jason A.

    2014-01-01

    Purpose We compared the metabolic profiles and the association between LDH-A expression and lactate production in two isogenic murine breast cancer cell lines and tumors (67NR and 4T1). These cell lines were derived from a single mammary tumor and have different growth and metabolic phenotypes. Experimental Design LDH-A expression, lactate concentration, glucose utilization and oxygen consumption were measured in cells, and the potential relationship between tumor lactate levels (measured by magnetic resonance spectroscopic imaging (MRSI)) and tumor glucose utilization (measured by [18F] 2-deoxy-2-fluoro-D-glucose positron emission tomography ([18F]FDG-PET)) was assessed in orthotopic breast tumors derived from these cell lines. Results We show a substantial difference in LDH-A expression between 67NR and 4T1 cells under normoxia and hypoxia. We also show that small orthotopic 4T1 tumors generate tenfold more lactate than corresponding 67NR tumors. The high lactate levels in small primary 4T1 tumors are associated with intense pimonidazole staining (a hypoxia indicator). Less intense hypoxia staining was observed in the larger 67NR tumors, and is consistent with the gradual increase and plateau of lactate concentration in enlarging 67NR tumors. Conclusions Lactate-MRSI has a greater dynamic range than [18F]FDG-PET and may be a more sensitive measure with which to evaluate the aggressive and metastatic potential of primary breast tumors. PMID:21844011

  9. The Effectiveness of Lactation Consultants and Lactation Counselors on Breastfeeding Outcomes.

    PubMed

    Patel, Sanjay; Patel, Shveta

    2016-08-01

    Breastfeeding for all infants starting at birth and continuing until at least 6 months of age has been recommended by the World Health Organization and the American Academy of Pediatrics. The health benefits to infants and mothers have been demonstrated in many studies. Dedicated lactation specialists may play a role in providing education and support to pregnant women and new mothers wishing to breastfeed to improve breastfeeding outcomes. The objective of this review was to assess if lactation education or support programs using lactation consultants or lactation counselors would improve rates of initiation and duration of any breastfeeding and exclusive breastfeeding compared with usual practice. A systematic literature review of the evidence was conducted using electronic databases. The review was limited to randomized trials and yielded 16 studies with 5084 participants. It was found that breastfeeding interventions using lactation consultants and counselors increase the number of women initiating breastfeeding (odds ratio [OR] for any initiation vs not initiating breastfeeding = 1.35; 95% confidence interval [CI], 1.10-1.67). The interventions improve any breastfeeding rates (OR for any breastfeeding up to 1 month vs not breastfeeding = 1.49; 95% CI, 1.09-2.04). In addition, there were beneficial effects on exclusive breastfeeding rates (OR for exclusive breastfeeding up to 1 month vs not exclusive breastfeeding = 1.71; 95% CI, 1.20-2.44). Most of the evidence would suggest developing and improving postpartum support programs incorporating lactation consultants and lactation counselors. PMID:26644419

  10. Diet for a Healthy Lactating Woman.

    PubMed

    Kolasa, Kathryn M; Firnhaber, Gina; Haven, Kelley

    2015-12-01

    The nutrient and caloric requirements for lactation are set by the Institute of Medicine. The dietary pattern to meet those needs is found in the Dietary Guidelines for Americans. Only deficiency states for selected nutrients and/or prolonged inadequate caloric intake appear to affect the volume and quality of breast milk. Other dietary concerns of lactating women include "dieting" to return to prepregnancy weight; low maternal intake of selected nutrients due to health conditions or food choices; need for supplementation of calcium, vitamin D, and fatty acids; and use of non-nutritive sweeteners, caffeine, herbal supplements, and alcohol. PMID:26398295

  11. Calcium metabolism in pregnancy and lactation

    PubMed Central

    White, C P

    2009-01-01

    Homeostatic adaptation to maternal calcium metabolism is a prerequisite for optimal delivery of sufficient calcium to the fetus and neonate during pregnancy and lactation, respectively. This article outlines the major adaptations known to occur and the physiological regulators likely to be principally involved. Importantly, different adaptive responses are used in pregnancy and lactation. The rarity of calcium disorders in pregnancy underscores the successful implementation of these adaptations in most women. For those few women with either pre-existing or pregnancy-acquired disorders of calcium metabolism, a knowledge of normal physiology is essential to understand the implications for managing these disorders in pregnant women.

  12. Identification of a mutation affecting an alanine-alpha-ketoisovalerate transaminase activity in Escherichia coli K-12.

    PubMed

    Falkinham, J O

    1979-10-01

    A mutation affecting alanine-alpha-ketoisovalerate transaminase activity has been shown to be cotransducible with ilv gene cluster. The transaminase deficiency results in conditional isoleucine auxotrophy in the presence of alanine. PMID:396446

  13. Folding simulations of alanine-based peptides with lysine residues.

    PubMed Central

    Sung, S S

    1995-01-01

    The folding of short alanine-based peptides with different numbers of lysine residues is simulated at constant temperature (274 K) using the rigid-element Monte Carlo method. The solvent-referenced potential has prevented the multiple-minima problem in helix folding. From various initial structures, the peptides with three lysine residues fold into helix-dominated conformations with the calculated average helicity in the range of 60-80%. The peptide with six lysine residues shows only 8-14% helicity. These results agree well with experimental observations. The intramolecular electrostatic interaction of the charged lysine side chains and their electrostatic hydration destabilize the helical conformations of the peptide with six lysine residues, whereas these effects on the peptides with three lysine residues are small. The simulations provide insight into the helix-folding mechanism, including the beta-bend intermediate in helix initiation, the (i, i + 3) hydrogen bonds, the asymmetrical helix propagation, and the asymmetrical helicities in the N- and C-terminal regions. These findings are consistent with previous studies. PMID:7756550

  14. Energy landscapes and global thermodynamics for alanine peptides

    NASA Astrophysics Data System (ADS)

    Somani, Sandeep; Wales, David J.

    2013-09-01

    We compare different approaches for computing the thermodynamics of biomolecular systems. Techniques based on parallel replicas evolving via molecular dynamics or Monte Carlo simulations produce overlapping histograms for the densities of states. In contrast, energy landscape methods employ a superposition partition function constructed from local minima of the potential energy surface. The latter approach is particularly powerful for systems exhibiting broken ergodicity, and it is usually implemented using a harmonic normal mode approximation, which has not been extensively tested for biomolecules. The present contribution compares these alternative approaches for small alanine peptides modelled using the CHARMM and AMBER force fields. Densities of states produced from canonical sampling using multiple temperature replicas provide accurate reference data to evaluate the effect of the harmonic normal mode approximation in the superposition calculations. This benchmarking lays foundations for the application of energy landscape methods to larger biomolecules. It will also provide well characterised model systems for developing enhanced sampling methods, and for the treatment of anharmonicity corresponding to individual local minima.

  15. Alanine-EPR as a transfer standard dosimetry system for low energy X radiation

    NASA Astrophysics Data System (ADS)

    Khoury, H. J.; da Silva, E. J.; Mehta, K.; de Barros, V. S.; Asfora, V. K.; Guzzo, P. L.; Parker, A. G.

    2015-11-01

    The purpose of this paper is to evaluate the use of alanine-EPR as a transfer standard dosimetry system for low energy X radiation, such as that in RS-2400, which operates in the range from 25 to 150 kV and 2 to 45 mA. Two types of alanine dosimeters were investigated. One is a commercial alanine pellets from Aérial-Centre de Ressources Technologiques, France and one was prepared in our laboratory (LMRI-DEN/UFPE). The EPR spectra of the irradiated dosimeters were recorded in the Nuclear Energy Department of UFPE, using a Bruker EMX10 EPR spectrometer operating in the X-band. The alanine-EPR dosimetry system was calibrated in the range of 20-220 Gy in this X-ray field, against an ionization chamber calibrated at the relevant X-ray energy with traceability to PTB. The results showed that both alanine dosimeters presented a linear dose response the same sensitivity, when the EPR signal was normalized to alanine mass. The total uncertainty in the measured dose was estimated to be about 3%. The results indicate that it is possible to use the alanine-EPR dosimetry system for validation of a low-energy X ray irradiator, such as RS-2400.

  16. Sodium dependency of L-alanine absorption in canine Thiry-Vella loops.

    PubMed

    Fleshler, B; Nelson, R A

    1970-03-01

    The effect of sodium on the absorption of L-alanine in vivo was tested by measuring the absorption of L-alanine from Thiry-Vella loops in dogs. Solutions containing L-alanine (10 or 50 mM) sodium at concentrations of 0, 74, or 145 m-equiv/1 and mannitol, as needed to maintain isotonicity were instilled into the loops for 10 minutes. Similar studies were done with L-alanine 50 mM and either 0 or 145 m-equiv/1 of sodium for five minutes. Under all conditions absorption of alanine was significantly less from the solution initially free of sodium. Although these differences were statistically significant, the physiological significance was not great since the actual differences in amounts of L-alanine absorbed were small. Insorption of sodium was low from the fluid which initially had no sodium, but exsorption proceeded rapidly and was unaffected by the luminal sodium concentration. This resulted in a rapid rise of intraluminal sodium concentration when no sodium was initially present. This persistent exsorption of sodium was, therefore, adequate to provide sodium in the lumen to activate the sodium-dependent carrier, postulated on the basis of studies in vitro. These data in vivo are consistent with the view that sodium at the intraluminal surface is important in accelerating amino acid transport, but indicate that in the absence of added intraluminal sodium the gut mucosa itself, under normal circumstances, provides the sodium needed for L-alanine absorption. PMID:5423904

  17. Novel Membrane Based Process for Producing Lactate Esters

    SciTech Connect

    1999-02-01

    Lactate Esters from Renewable Carbohydrate Feedstocks can Replace Petroleum-Derived Solvents. Lactate esters are versatile solvents that are biodegradable, nontoxic, and applicable to a wide range of industrial and consumer uses.

  18. LactMed: New NLM Database on Drugs and Lactation

    MedlinePlus

    ... Issues Research News From NIH LactMed: New NLM Database on Drugs and Lactation Past Issues / Summer 2006 ... Javascript on. Photo: Comstock LactMed, a free online database with information on drugs and lactation, is one ...

  19. LactMed: New NLM Database on Drugs and Lactation

    MedlinePlus

    ... Current Issue Past Issues Research News From NIH LactMed: New NLM Database on Drugs and Lactation Past ... milk, infant levels in blood, potential effects in breast-feeding infants and on lactation itself. The American Academy ...

  20. Mitochondrial defects associated with β-alanine toxicity: relevance to hyper-beta-alaninemia.

    PubMed

    Shetewy, Aza; Shimada-Takaura, Kayoko; Warner, Danielle; Jong, Chian Ju; Mehdi, Abu-Bakr Al; Alexeyev, Mikhail; Takahashi, Kyoko; Schaffer, Stephen W

    2016-05-01

    Hyper-beta-alaninemia is a rare metabolic condition that results in elevated plasma and urinary β-alanine levels and is characterized by neurotoxicity, hypotonia, and respiratory distress. It has been proposed that at least some of the symptoms are caused by oxidative stress; however, only limited information is available on the mechanism of reactive oxygen species generation. The present study examines the hypothesis that β-alanine reduces cellular levels of taurine, which are required for normal respiratory chain function; cellular taurine depletion is known to reduce respiratory function and elevate mitochondrial superoxide generation. To test the taurine hypothesis, isolated neonatal rat cardiomyocytes and mouse embryonic fibroblasts were incubated with medium lacking or containing β-alanine. β-alanine treatment led to mitochondrial superoxide accumulation in conjunction with a decrease in oxygen consumption. The defect in β-alanine-mediated respiratory function was detected in permeabilized cells exposed to glutamate/malate but not in cells utilizing succinate, suggesting that β-alanine leads to impaired complex I activity. Taurine treatment limited mitochondrial superoxide generation, supporting a role for taurine in maintaining complex I activity. Also affected by taurine is mitochondrial morphology, as β-alanine-treated fibroblasts undergo fragmentation, a sign of unhealthy mitochondria that is reversed by taurine treatment. If left unaltered, β-alanine-treated fibroblasts also undergo mitochondrial apoptosis, as evidenced by activation of caspases 3 and 9 and the initiation of the mitochondrial permeability transition. Together, these data show that β-alanine mediates changes that reduce ATP generation and enhance oxidative stress, factors that contribute to heart failure. PMID:27023909

  1. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF...

  2. 21 CFR 582.1207 - Calcium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium lactate. 582.1207 Section 582.1207 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose...

  3. ENERGY REQUIREMENTS DURING PREGNANCY AND LACTATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To estimate the energy requirements of pregnant and lactating women consistent with optimal pregnancy outcome and adequate milk production. Design: Total energy cost of pregnancy was estimated using the factorial approach from pregnancy-induced increments in basal metabolic rate measured...

  4. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferrous lactate. 582.5311 Section 582.5311 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

  5. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ferrous lactate. 582.5311 Section 582.5311 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

  6. Microbial production of lactate-containing polyesters

    PubMed Central

    Yang, Jung Eun; Choi, So Young; Shin, Jae Ho; Park, Si Jae; Lee, Sang Yup

    2013-01-01

    Due to our increasing concerns on environmental problems and limited fossil resources, biobased production of chemicals and materials through biorefinery has been attracting much attention. Optimization of the metabolic performance of microorganisms, the key biocatalysts for the efficient production of the desired target bioproducts, has been achieved by metabolic engineering. Metabolic engineering allowed more efficient production of polyhydroxyalkanoates, a family of microbial polyesters. More recently, non-natural polyesters containing lactate as a monomer have also been produced by one-step fermentation of engineered bacteria. Systems metabolic engineering integrating traditional metabolic engineering with systems biology, synthetic biology, protein/enzyme engineering through directed evolution and structural design, and evolutionary engineering, enabled microorganisms to efficiently produce natural and non-natural products. Here, we review the strategies for the metabolic engineering of microorganisms for the in vivo biosynthesis of lactate-containing polyesters and for the optimization of whole cell metabolism to efficiently produce lactate-containing polyesters. Also, major problems to be solved to further enhance the production of lactate-containing polyesters are discussed. PMID:23718266

  7. Biomonitoring Polybrominated Diphenyl Ethers in Lactating Women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breast milk is a valuable biological specimen for biomonitoring lipid-soluble polybrominated diphenyl ethers (PBDEs). The goal of this project was to determine the levels of PBDEs in breast milk of lactating women from the Seacoast region of New Hampshire and to examine potential relationships betw...

  8. Studying Reliability Using Identical Handheld Lactate Analyzers

    ERIC Educational Resources Information Center

    Stewart, Mark T.; Stavrianeas, Stasinos

    2008-01-01

    Accusport analyzers were used to generate lactate performance curves in an investigative laboratory activity emphasizing the importance of reliable instrumentation. Both the calibration and testing phases of the exercise provided students with a hands-on opportunity to use laboratory-grade instrumentation while allowing for meaningful connections…

  9. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (c) Uses and restrictions. Ferrous lactate may...

  10. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (c) Uses and restrictions. Ferrous lactate may...

  11. Characterization of the l-alanine exporter AlaE of Escherichia coli and its potential role in protecting cells from a toxic-level accumulation of l-alanine and its derivatives

    PubMed Central

    Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Hori, Hatsuhiro; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2015-01-01

    We previously reported that the alaE gene of Escherichia coli encodes the l-alanine exporter AlaE. The objective of this study was to elucidate the mechanism of the AlaE exporter. The minimum inhibitory concentration of l-alanine and l-alanyl-l-alanine in alaE-deficient l-alanine-nonmetabolizing cells MLA301ΔalaE was 4- and >4000-fold lower, respectively, than in the alaE-positive parent cells MLA301, suggesting that AlaE functions as an efflux pump to avoid a toxic-level accumulation of intracellular l-alanine and its derivatives. Furthermore, the growth of the alaE-deficient mutant derived from the l-alanine-metabolizing strain was strongly inhibited in the presence of a physiological level of l-alanyl-l-alanine. Intact MLA301ΔalaE and MLA301ΔalaE/pAlaE cells producing plasmid-borne AlaE, accumulated approximately 200% and 50%, respectively, of the [3H]l-alanine detected in MLA301 cells, suggesting that AlaE exports l-alanine. When 200 mmol/L l-alanine-loaded inverted membrane vesicles prepared from MLA301ΔalaE/pAlaE were placed in a solution containing 200 mmol/L or 0.34 μmol/L l-alanine, energy-dependent [3H]l-alanine accumulation occurred under either condition. This energy-dependent uphill accumulation of [3H]l-alanine was strongly inhibited in the presence of carbonyl cyanide m-chlorophenylhydrazone but not by dicyclohexylcarbodiimide, suggesting that the AlaE-mediated l-alanine extrusion was driven by proton motive force. Based on these results, physiological roles of the l-alanine exporter are discussed. PMID:26073055

  12. Characterization of the l-alanine exporter AlaE of Escherichia coli and its potential role in protecting cells from a toxic-level accumulation of l-alanine and its derivatives.

    PubMed

    Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Hori, Hatsuhiro; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2015-08-01

    We previously reported that the alaE gene of Escherichia coli encodes the l-alanine exporter AlaE. The objective of this study was to elucidate the mechanism of the AlaE exporter. The minimum inhibitory concentration of l-alanine and l-alanyl-l-alanine in alaE-deficient l-alanine-nonmetabolizing cells MLA301ΔalaE was 4- and >4000-fold lower, respectively, than in the alaE-positive parent cells MLA301, suggesting that AlaE functions as an efflux pump to avoid a toxic-level accumulation of intracellular l-alanine and its derivatives. Furthermore, the growth of the alaE-deficient mutant derived from the l-alanine-metabolizing strain was strongly inhibited in the presence of a physiological level of l-alanyl-l-alanine. Intact MLA301ΔalaE and MLA301ΔalaE/pAlaE cells producing plasmid-borne AlaE, accumulated approximately 200% and 50%, respectively, of the [(3) H]l-alanine detected in MLA301 cells, suggesting that AlaE exports l-alanine. When 200 mmol/L l-alanine-loaded inverted membrane vesicles prepared from MLA301ΔalaE/pAlaE were placed in a solution containing 200 mmol/L or 0.34 μmol/L l-alanine, energy-dependent [(3) H]l-alanine accumulation occurred under either condition. This energy-dependent uphill accumulation of [(3) H]l-alanine was strongly inhibited in the presence of carbonyl cyanide m-chlorophenylhydrazone but not by dicyclohexylcarbodiimide, suggesting that the AlaE-mediated l-alanine extrusion was driven by proton motive force. Based on these results, physiological roles of the l-alanine exporter are discussed. PMID:26073055

  13. Expression and purification of a functional recombinant aspartate aminotransferase (AST) from Escherichia coli.

    PubMed

    Zou, Lihui; Zhao, Haijian; Wang, Daguang; Wang, Meng; Zhang, Chuanbao; Xiao, Fei

    2014-07-01

    Aspartate aminotransferase (AST; E.C. 2.6.1.1), a vitamin B6-dependent enzyme, preferentially promotes the mutual transformation of aspartate and α-ketoglutarate to oxaloacetate and glutamate. It plays a key role in amino acid metabolism and has been widely recommended as a biomarker of liver and heart damage. Our study aimed to evaluate the extensive preparation of AST and its application in quality control in clinical laboratories. We describe a scheme to express and purify the 6His-AST fusion protein. An optimized sequence coding AST was synthesized and transformed into Escherichia coli BL21 (DE3) strain for protein expression. Ideally, the fusion protein has a volumetric productivity achieving 900 mg/l cultures. After affinity chromatography, the enzyme activity of purified AST reached 150,000 U/L. Commutability assessment between the engineered AST and standard AST from Roche suggested that the engineered AST was the better candidate for the reference material. Moreover, the AST showed high stability during long-term storage at -20ºC. In conclusion, the highly soluble 6His-tagged AST can become a convenient tool for supplying a much better and cheaper standard or reference material for the clinical laboratory. PMID:24722375

  14. L-lysine epsilon-aminotransferase involved in cephamycin C synthesis in Streptomyces lactamdurans.

    PubMed Central

    Kern, B A; Hendlin, D; Inamine, E

    1980-01-01

    In Streptomyces lactamdurans, the precursor of the alpha-aminoadipoyl side-chain of cephamycin C is L-lysine. In this regard, streptomycetes differ strikingly from the fungi, which produce alpha-aminoadipic acid during the synthesis, rather than the breakdown, of L-lysine. Studies using a cell-free system showed that an aminoadipic acid. The product of this reaction was trapped and subsequently purified by ion-exchange chromatography. Thin-layer chromatography, spectrophotometry, and amino acid oxidase digestion studies identified the reaction product as L-1-piperideine-6-carboxylate, implying enzymatic removal of the epsilon amino group of L-lysine. This enzymatic activity (E.C. 2.6.1.36; L-lysine: 2-oxoglutarate 6-aminotransferase) is highly unusual and was previously conclusively demonstrated only in the genus Flavobacterium. In S. lactamdurans, the specific activity of this enzyme reaches a peak early in the fermentation (approximately 20 h) and decreases as the antibiotic begins to appear. PMID:6772093

  15. Design and mechanism of tetrahydrothiophene-based γ-aminobutyric acid aminotransferase inactivators.

    PubMed

    Le, Hoang V; Hawker, Dustin D; Wu, Rui; Doud, Emma; Widom, Julia; Sanishvili, Ruslan; Liu, Dali; Kelleher, Neil L; Silverman, Richard B

    2015-04-01

    Low levels of γ-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinson's disease, Alzheimer's disease, Huntington's disease, and cocaine addiction. One of the main methods to raise the GABA level in human brain is to use small molecules that cross the blood-brain barrier and inhibit the activity of γ-aminobutyric acid aminotransferase (GABA-AT), the enzyme that degrades GABA. We have designed a series of conformationally restricted tetrahydrothiophene-based GABA analogues with a properly positioned leaving group that could facilitate a ring-opening mechanism, leading to inactivation of GABA-AT. One compound in the series is 8 times more efficient an inactivator of GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. Our mechanistic studies show that the compound inactivates GABA-AT by a new mechanism. The metabolite resulting from inactivation does not covalently bind to amino acid residues of GABA-AT but stays in the active site via H-bonding interactions with Arg-192, a π-π interaction with Phe-189, and a weak nonbonded S···O═C interaction with Glu-270, thereby inactivating the enzyme. PMID:25781189

  16. Comparison of Prothrombin Time and Aspartate Aminotransferase in Predicting Hepatotoxicity After Acetaminophen Overdose.

    PubMed

    Levine, Michael; O'Connor, Ayrn D; Padilla-Jones, Angela; Gerkin, Richard D

    2016-03-01

    Despite decades of experience with acetaminophen (APAP) overdoses, it remains unclear whether elevated hepatic transaminases or coagulopathy develop first. Furthermore, comparison of the predictive value of these two variables in determining hepatic toxicity following APAP overdoses has been poorly elucidated. The primary objective of this study is to determine the test characteristics of the aspartate aminotransferase (AST) and the prothrombin time (PT) in patients with APAP toxicity. A retrospective chart review of APAP overdoses treated with IV N-acetylcysteine at a tertiary care referral center was performed. Of the 304 subjects included in the study, 246 with an initial AST less than 1000 were analyzed to determine predictors of hepatic injury, defined as an AST exceeding 1000 IU/L. The initial AST >50 was 79.5 % sensitive and 82.6 % specific for predicting hepatic injury. The corresponding negative and positive predictive values were 95.5 and 46.3 %, respectively. In contrast, an initial abnormal PT had a sensitivity of 82.1 % and a specificity of 63.6 %. The negative and positive predictive values for initial PT were 94.9 and 30.2 %, respectively. Although the two tests performed similarly for predicting a composite endpoint of death or liver transplant, neither was a useful predictor. Initial AST performed better than the initial PT for predicting hepatic injury in this series of patients with APAP overdose. PMID:26341088

  17. Ornithine-δ-aminotransferase is essential for Arginine Catabolism but not for Proline Biosynthesis

    PubMed Central

    Funck, Dietmar; Stadelhofer, Bettina; Koch, Wolfgang

    2008-01-01

    Background Like many other plant species, Arabidopsis uses arginine (Arg) as a storage and transport form of nitrogen, and proline (Pro) as a compatible solute in the defence against abiotic stresses causing water deprivation. Arg catabolism produces ornithine (Orn) inside mitochondria, which was discussed controversially as a precursor for Pro biosynthesis, alternative to glutamate (Glu). Results We show here that ornithine-δ-aminotransferase (δOAT, At5g46180), the enzyme converting Orn to pyrroline-5-carboxylate (P5C), is localised in mitochondria and is essential for Arg catabolism. Wildtype plants could readily catabolise supplied Arg and Orn and were able to use these amino acids as the only nitrogen source. Deletion mutants of δOAT, however, accumulated urea cycle intermediates when fed with Arg or Orn and were not able to utilize nitrogen provided as Arg or Orn. Utilisation of urea and stress induced Pro accumulation were not affected in T-DNA insertion mutants with a complete loss of δOAT expression. Conclusion Our findings indicate that δOAT feeds P5C exclusively into the catabolic branch of Pro metabolism, which yields Glu as an end product. Conversion of Orn to Glu is an essential route for recovery of nitrogen stored or transported as Arg. Pro biosynthesis occurs predominantly or exclusively via the Glu pathway in Arabidopsis and does not depend on Glu produced by Arg and Orn catabolism. PMID:18419821

  18. Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana.

    PubMed

    Sandorf, Iris; Holländer-Czytko, Heike

    2002-11-01

    Coronatine-inducible tyrosine aminotransferase (TAT), which catalyses the transamination from tyrosine to p-hydroxyphenylpyruvate, is the first enzyme of a pathway leading via homogentisic acid to plastoquinone and tocopherols, the latter of which are known to be radical scavengers in plants. TAT can be also induced by the octadecanoids methyl jasmonate (MeJA) and methyl-12-oxophytodienoic acid (MeOPDA), as well as by wounding, high light, UV light and the herbicide oxyfluorfen. In order to elucidate the role of octadecanoids in the process of TAT induction in Arabidopsis thaliana (L.) Heynh., the jasmonate-deficient mutant delayed dehiscence (dde1) was used, in which the gene for 12-oxophytodienoic acid reductase 3 is disrupted. The amount of immunodetectable TAT was low. The enzyme was still fully induced by coronatine as well as by MeJA although induction by the latter was to a lesser extent and later than in the wild type. Treatment with MeOPDA, wounding and UV light, however, had hardly any effects. Tocopherol levels that showed considerable increases in the wild type after some treatments were much less affected in the mutant. However, starting levels of tocopherol were higher in non-induced dde1 than in the wild type. We conclude that jasmonate plays an important role in the signal transduction pathway regulating TAT activity and the biosynthesis of its product tocopherol. PMID:12430028

  19. Structural Basis for the Stereochemical Control of Amine Installation in Nucleotide Sugar Aminotransferases.

    PubMed

    Wang, Fengbin; Singh, Shanteri; Xu, Weijun; Helmich, Kate E; Miller, Mitchell D; Cao, Hongnan; Bingman, Craig A; Thorson, Jon S; Phillips, George N

    2015-09-18

    Sugar aminotransferases (SATs) are an important class of tailoring enzymes that catalyze the 5'-pyridoxal phosphate (PLP)-dependent stereo- and regiospecific installation of an amino group from an amino acid donor (typically L-Glu or L-Gln) to a corresponding ketosugar nucleotide acceptor. Herein we report the strategic structural study of two homologous C4 SATs (Micromonospora echinospora CalS13 and Escherichia coli WecE) that utilize identical substrates but differ in their stereochemistry of aminotransfer. This study reveals for the first time a new mode of SAT sugar nucleotide binding and, in conjunction with previously reported SAT structural studies, provides the basis from which to propose a universal model for SAT stereo- and regiochemical control of amine installation. Specifically, the universal model put forth highlights catalytic divergence to derive solely from distinctions within nucleotide sugar orientation upon binding within a relatively fixed SAT active site where the available ligand bound structures of the three out of four representative C3 and C4 SAT examples provide a basis for the overall model. Importantly, this study presents a new predictive model to support SAT functional annotation, biochemical study and rational engineering. PMID:26023720

  20. CPP-115, a Potent γ-Aminobutyric Acid Aminotransferase Inactivator for the Treatment of Cocaine Addiction

    PubMed Central

    Pan, Yue; Gerasimov, Madina R.; Kvist, Trine; Wellendorph, Petrine; Madsen, Karsten K.; Pera, Elena; Lee, Hyunbeom; Schousboe, Arne; Chebib, Mary; Bräuner-Osborne, Hans; Craft, Cheryl M.; Brodie, Jonathan D.; Schiffer, Wynne K.; Dewey, Stephen L.; Miller, Steven R.; Silverman, Richard B.

    2011-01-01

    Vigabatrin, a GABA aminotransferase (GABA-AT) inactivator, is used to treat infantile spasms and refractory complex partial seizures and is in clinical trials to treat addiction. We evaluated a novel GABA-AT inactivator (CPP-115) and observed that it does not exhibit other GABAergic or off-target activities and is rapidly and completely orally absorbed and eliminated. Using in vivo microdialysis techniques in freely moving rats and micro-PET imaging techniques, CPP-115 produced similar inhibition of cocaine-induced increases in extracellular dopamine and in synaptic dopamine in the nucleus accumbens at 1/300–1/600th the dose of vigabatrin. It also blocks expression of cocaine-induced conditioned place preference at a dose 1/300th that of vigabatrin. Electroretinographic (ERG) responses in rats treated with CPP-115, at doses 20–40 times higher than those needed to treat addiction in rats, exhibited reductions in ERG responses, which were less than the reductions observed in rats treated with vigabatrin at the same dose needed to treat addiction in rats. In conclusion, CPP-115 can be administered at significantly lower doses than vigabatrin, which suggests a potential new treatment for addiction with a significantly reduced risk of visual field defects. PMID:22128851

  1. Aspartate aminotransferase activity in the pulp of teeth treated for 6 months with fixed orthodontic appliances

    PubMed Central

    Latkauskiene, Dalia; Racinskaite, Vilma; Skucaite, Neringa; Machiulskiene, Vita

    2015-01-01

    Objective To measure aspartate aminotransferase (AST) activity in the pulp of teeth treated with fixed appliances for 6 months, and compare it with AST activity measured in untreated teeth. Methods The study sample consisted of 16 healthy subjects (mean age 25.7 ± 4.3 years) who required the extraction of maxillary premolars for orthodontic reasons. Of these, 6 individuals had a total of 11 sound teeth extracted without any orthodontic treatment (the control group), and 10 individuals had a total of 20 sound teeth extracted after 6 months of orthodontic alignment (the experimental group). Dental pulp samples were extracted from all control and experimental teeth, and the AST activity exhibited by these samples was determined spectrophotometrically at 20℃. Results Mean AST values were 25.29 × 10-5 U/mg (standard deviation [SD] 9.95) in the control group and 27.54 × 10-5 U/mg (SD 31.81) in the experimental group. The difference between these means was not statistically significantly (p = 0.778), and the distribution of the AST values was also similar in both groups. Conclusions No statistically significant increase in AST activity in the pulp of mechanically loaded teeth was detected after 6 months of orthodontic alignment, as compared to that of teeth extracted from individuals who had not undergone orthodontic treatment. This suggests that time-related regenerative processes occur in the dental pulp. PMID:26445721

  2. Novel protein-protein interactions between Entamoeba histolyticad-phosphoglycerate dehydrogenase and phosphoserine aminotransferase.

    PubMed

    Mishra, Vibhor; Kumar, Ashutosh; Ali, Vahab; Nozaki, Tomoyoshi; Zhang, Kam Y J; Bhakuni, Vinod

    2012-08-01

    Physical interactions between d-phosphoglycerate dehydrogenase (EhPGDH) and phosphoserine aminotransferase (EhPSAT) from an enteric human parasite Entamoeba histolytica was observed by pull-down assay, gel filtration chromatography, chemical cross-linking, emission anisotropy, molecular docking and molecular dynamic simulations. The protein-protein complex had a 1:1 stochiometry with a dissociation constant of 3.453 × 10(-7) M. Ionic interactions play a significant role in complex formation and stability. Analysis of the energy minimized average simulated model of the protein complex show that the nucleotide binding domain of EhPGDH specifically interacts with EhPSAT. Denaturation studies suggest that the nucleotide binding domain (Nbd) and substrate binding domain (Sbd) of EhPGDH are independent folding/unfolding units. Thus the Nbd-EhPGDH was separately cloned over-expressed and purified to homogeneity. Fluorescence anisotropy study show that the purified Nbd interacts with EhPSAT. Forward enzyme catalyzed reaction for the EhPGDH-PSAT complex showed efficient Km values for 3-phosphoglyceric acid as compared to only EhPGDH suggesting a possibility of substrate channelling in the protein complex. PMID:22386871

  3. The rice FISH BONE gene encodes a tryptophan aminotransferase, which affects pleiotropic auxin-related processes.

    PubMed

    Yoshikawa, Takanori; Ito, Momoyo; Sumikura, Tsuyoshi; Nakayama, Akira; Nishimura, Takeshi; Kitano, Hidemi; Yamaguchi, Isomaro; Koshiba, Tomokazu; Hibara, Ken-Ichiro; Nagato, Yasuo; Itoh, Jun-Ichi

    2014-06-01

    Auxin is a fundamental plant hormone and its localization within organs plays pivotal roles in plant growth and development. Analysis of many Arabidopsis mutants that were defective in auxin biosynthesis revealed that the indole-3-pyruvic acid (IPA) pathway, catalyzed by the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) and YUCCA (YUC) families, is the major biosynthetic pathway of indole-3-acetic acid (IAA). In contrast, little information is known about the molecular mechanisms of auxin biosynthesis in rice. In this study, we identified a auxin-related rice mutant, fish bone (fib). FIB encodes an orthologue of TAA genes and loss of FIB function resulted in pleiotropic abnormal phenotypes, such as small leaves with large lamina joint angles, abnormal vascular development, small panicles, abnormal organ identity and defects in root development, together with a reduction in internal IAA levels. Moreover, we found that auxin sensitivity and polar transport activity were altered in the fib mutant. From these results, we suggest that FIB plays a pivotal role in IAA biosynthesis in rice and that auxin biosynthesis, transport and sensitivity are closely interrelated. PMID:24654985

  4. Molecular basis of ornithine aminotransferase deficiency in B-6-responsive and -nonresponsive forms of gyrate atrophy

    SciTech Connect

    Ramesh, V.; McClatchey, A.I.; Ramesh, N.; Benoit, L.A.; Berson, E.L.; Shih, V.E.; Gusella, J.F. )

    1988-06-01

    Gyrate atrophy (GA), a recessive eye disease involving progressive loss of vision due to chorioretinal degeneration, is associated with a deficiency of the mitochondrial enzyme ornithine aminotransferase with consequent hyperornithinemia. Genetic heterogeneity of GA has been suggested by the demonstration that administration of pyridoxine to increase the level of pyridoxal phosphate, a cofactor of OATase, reduces hyperornithinemia in a subset of patients. The authors have cloned and sequences cDNAs for OATase from two GA patients, one responsive and one nonresponsive to pyridoxine treatment. The respective cDNAs contained different single missense mutations, which were sufficient to eliminate OATase activity when each cDNA was tested in a eukaryotic expression system. However, like the enzyme in fibroblasts from the pyridoxine-responsive patient, OATase encoded by the corresponding cDNA from this individual showed a significant increase in activity when assayed in the presence of an increased pyridoxal phosphate concentration. These data firmly establish that both pyridoxine responsive and nonresponsive forms of GA result from mutations in the OATase structural gene. Moreover, they provide a molecular characterization of the primary lesion in a pyridoxine-responsive genetic disorder.

  5. Effects of self-association of ornithine aminotransferase on its physicochemical characteristics

    SciTech Connect

    Boernke, W.E.; Stevens, F.J.; Peraino, C.

    1981-01-01

    Previous work in this laboratory has shown that the molecular weight of ornithine aminotransferase (OAT) is concentration dependent. In the present study this property of OAT was further characterized by using sedimentation equilibrium centrifugation to determine the molecular weight of OAT in a range of enzyme concentrations. It was shown that OAT aggregates in a two-stage process as its concentration increases. The first stage involves the association of enzymatically active monomers into trimers, with association of the trimmers into higher order aggregates occurring in the second stage. Decreasing the pH or raising the ionic strength enhanced aggregation, while raising the pH inhibits aggregation; however, the two-stage nature of the aggregation process was not affected by changes in pH and ionic strength. Kinetic analyses of purified enzyme showed that aggregatio results in an increase in the K/sub m/ for both substrates with the V/sub max/ remaining constant, indicating that aggregation of monomers sterically hinders substrate binding. Increased K/sub m/ values were also obtained for OAT sequestered in mitochondia from rats fed a high-protein diet to increase mitochondrial OAT levels. The higher K/sub m/ values suggest that the elevation of OAT in vivo is accompanied by aggregation of the enzyme within the mitochondrion. We propose that the aggregation-dependent increase of K/sub m/ in vivo has adaptive value in that it spares ornithine for use in the urea cycle.

  6. Structural Insight into the Inhibition of Human Kynurenine Aminotransferase I/Glutamine Transaminase K

    SciTech Connect

    Han, Q.; Robinson, H; Cai, T; Tagle, D; Li, J

    2009-01-01

    Human kynurenine aminotransferase I (hKAT I) catalyzes the formation of kynurenic acid, a neuroactive compound. Here, we report three high-resolution crystal structures (1.50-1.55 A) of hKAT I that are in complex with glycerol and each of two inhibitors of hKAT I: indole-3-acetic acid (IAC) and Tris. Because Tris is able to occupy the substrate binding position, we speculate that this may be the basis for hKAT I inhibition. Furthermore, the hKAT/IAC complex structure reveals that the binding moieties of the inhibitor are its indole ring and a carboxyl group. Six chemicals with both binding moieties were tested for their ability to inhibit hKAT I activity; 3-indolepropionic acid and dl-indole-3-lactic acid demonstrated the highest level of inhibition, and as they cannot be considered as substrates of the enzyme, these two inhibitors are promising candidates for future study. Perhaps even more significantly, we report the discovery of two different ligands located simultaneously in the hKAT I active center for the first time.

  7. Effect of anthocyanin-rich corn silage on digestibility, milk production and plasma enzyme activities in lactating dairy cows.

    PubMed

    Hosoda, Kenji; Eruden, Bayaru; Matsuyama, Hiroki; Shioya, Shigeru

    2012-06-01

    Anthocyanin in purple corn (Zea mays L.) has been reported to show several functional and biological attributes, displaying antioxidant, antiobesity and antidiabetic effects in monogastric animals. The objective of this study was to investigate the effect of feeding anthocyanin-rich corn (Zea mays L., Choko C922) silage on digestibility, milk production and plasma enzyme activities in lactating dairy cows. The cows were fed diets based on the control corn or the anthocyanin-rich corn silage (AR treatment) in a crossover design. The anthocyanin-rich corn silage-based diet had a lower starch content, nutrient digestibility and total digestible nutrients content when compared to the control diet. The milk yield, lactose and solids-not-fat contents in the AR-treatment cows were lower than in the control cows. The feeding of the anthocyanin-rich corn silage led to a reduction in aspartate aminotransferase (AST) activity and an increase in superoxide dismutase (SOD) activity in the plasma. These data suggest that the anthocyanin-rich corn has a lowering effect on AST activity with concomitant enhancement of SOD activity in lactating dairy cows. However, a new variety of anthocyanin-rich corn with good nutritional value is needed for practical use as a ruminant feed. PMID:22694328

  8. Inducible l-Alanine Exporter Encoded by the Novel Gene ygaW (alaE) in Escherichia coli ▿

    PubMed Central

    Hori, Hatsuhiro; Yoneyama, Hiroshi; Tobe, Ryuta; Ando, Tasuke; Isogai, Emiko; Katsumata, Ryoichi

    2011-01-01

    We previously isolated a mutant hypersensitive to l-alanyl-l-alanine from a non-l-alanine-metabolizing Escherichia coli strain and found that it lacked an inducible l-alanine export system. Consequently, this mutant showed a significant accumulation of intracellular l-alanine and a reduction in the l-alanine export rate compared to the parent strain. When the mutant was used as a host to clone a gene(s) that complements the dipeptide-hypersensitive phenotype, two uncharacterized genes, ygaW and ytfF, and two characterized genes, yddG and yeaS, were identified. Overexpression of each gene in the mutant resulted in a decrease in the intracellular l-alanine level and enhancement of the l-alanine export rate in the presence of the dipeptide, suggesting that their products function as exporters of l-alanine. Since ygaW exhibited the most striking impact on both the intra- and the extracellular l-alanine levels among the four genes identified, we disrupted the ygaW gene in the non-l-alanine-metabolizing strain. The resulting isogenic mutant showed the same intra- and extracellular l-alanine levels as observed in the dipeptide-hypersensitive mutant obtained by chemical mutagenesis. When each gene was overexpressed in the wild-type strain, which does not intrinsically excrete alanine, only the ygaW gene conferred on the cells the ability to excrete alanine. In addition, expression of the ygaW gene was induced in the presence of the dipeptide. On the basis of these results, we concluded that YgaW is likely to be the physiologically most relevant exporter for l-alanine in E. coli and proposed that the gene be redesignated alaE for alanine export. PMID:21531828

  9. L-Lactate transport into rat heart mitochondria and reconstruction of the L-lactate/pyruvate shuttle.

    PubMed Central

    Valenti, Daniela; de Bari, Lidia; Atlante, Anna; Passarella, Salvatore

    2002-01-01

    In vitro reconstruction of the L-lactate/pyruvate shuttle has been performed, which allows NADH oxidation outside rat heart mitochondria. Such a shuttle occurs due to the combined action of the novel mitochondrial L-lactate/pyruvate antiporter, which differs from the monocarboxylate carrier, and the mitochondrial L-lactate dehydrogenase. The rate of L-lactate/pyruvate antiport proved to regulate the shuttle in vitro. PMID:11988081

  10. L-Lactate transport into rat heart mitochondria and reconstruction of the L-lactate/pyruvate shuttle.

    PubMed

    Valenti, Daniela; de Bari, Lidia; Atlante, Anna; Passarella, Salvatore

    2002-05-15

    In vitro reconstruction of the L-lactate/pyruvate shuttle has been performed, which allows NADH oxidation outside rat heart mitochondria. Such a shuttle occurs due to the combined action of the novel mitochondrial L-lactate/pyruvate antiporter, which differs from the monocarboxylate carrier, and the mitochondrial L-lactate dehydrogenase. The rate of L-lactate/pyruvate antiport proved to regulate the shuttle in vitro. PMID:11988081

  11. Solvation free energies of alanine peptides: the effect of flexibility.

    PubMed

    Kokubo, Hironori; Harris, Robert C; Asthagiri, Dilipkumar; Pettitt, B Montgomery

    2013-12-27

    The electrostatic (ΔGel), van der Waals cavity-formation (ΔGvdw), and total (ΔG) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with fixed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ΔGel, and components ΔGvdw, and ΔG, were found to be linear in n, with the slopes of the best-fit lines being γel, γvdw, and γ, respectively. Both γel and γ were negative for fixed and flexible peptides, and γvdw was negative for fixed peptides. That γvdw was negative was surprising, as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that γvdw should be positive. A negative γvdw seemingly contradicts the notion that ΔGvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas. When we computed ΔGvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, γvdw was positive. Because most proteins do not assume extended conformations, a ΔGvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We find few intramolecular H-bonds but show that the intramolecular van der Waals interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis. The large fluctuations in the vdw energy may make attributing the collapse of the peptide to this intramolecular energy difficult. PMID:24328358

  12. Solvation Free Energies of Alanine Peptides: The Effect of Flexibility

    PubMed Central

    Kokubo, Hironori; Harris, Robert C.; Asthigiri, Dilipkumar; Pettitt, B. Montgomery

    2014-01-01

    The electrostatic (ΔGel), van der Waals cavity-formation (ΔGvdw), and total (ΔG) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with fixed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ΔGel, and components ΔGvdw, and ΔG, were found to be linear in n, with the slopes of the best-fit lines being γel, γvdw, and γ, respectively. Both γel and γ were negative for fixed and flexible peptides, and γvdw was negative for fixed peptides. That γvdw was negative was surprising, as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that γvdw should be positive. A negative γvdw seemingly contradicts the notion that ΔGvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas. When we computed ΔGvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, γvdw was positive. Because most proteins do not assume extended conformations, a ΔGvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We find few intramolecular h-bonds but show that the intramolecular van der Waal’s interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis. The large fluctuations in the vdw energy may make attributing the collapse of the peptide to this intramolecular energy difficult. PMID:24328358

  13. Solvation Free Energies of Alanine Peptides: The Effect of Flexibility

    SciTech Connect

    Kokubo, Hironori; Harris, Robert C.; Asthagiri, Dilip; Pettitt, Bernard M.

    2013-12-03

    The electrostatic (?Gel), cavity-formation (?Gvdw), and total (?G) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with xed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ?Gel, ?Gvdw, and ?G, were found to be linear in n, with the slopes of the best-fit lines being gamma_el, gamma_vdw, and gamma, respectively. Both gamma_el and gamma were negative for fixed and flexible peptides, and gamma_vdw was negative for fixed peptides. That gamma_vdw was negative was surprising, as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that gamma_vdw should be positive. A negative gamma_vdw seemingly contradicts the notion that ?Gvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas, but when we computed ?Gvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, gamma-vdw was positive. Because most proteins do not assume extended conformations, a ?Gvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We show that the intramolecular van der Waal's interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis, but the large fluctuations in this energy may make attributing the collapse of the peptide to this intramolecular energy difficult.

  14. Structural characterization of AtmS13, a putative sugar aminotransferase involved in indolocarbazole AT2433 aminopentose biosynthesis.

    PubMed

    Singh, Shanteri; Kim, Youngchang; Wang, Fengbin; Bigelow, Lance; Endres, Michael; Kharel, Madan K; Babnigg, Gyorgy; Bingman, Craig A; Joachimiak, Andrzej; Thorson, Jon S; Phillips, George N

    2015-08-01

    AT2433 from Actinomadura melliaura is an indolocarbazole antitumor antibiotic structurally distinguished by its unique aminodideoxypentose-containing disaccharide moiety. The corresponding sugar nucleotide-based biosynthetic pathway for this unusual sugar derives from comparative genomics where AtmS13 has been suggested as the contributing sugar aminotransferase (SAT). Determination of the AtmS13 X-ray structure at 1.50-Å resolution reveals it as a member of the aspartate aminotransferase fold type I (AAT-I). Structural comparisons of AtmS13 with homologous SATs that act upon similar substrates implicate potential active site residues that contribute to distinctions in sugar C5 (hexose vs. pentose) and/or sugar C2 (deoxy vs. hydroxyl) substrate specificity. PMID:26061967

  15. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the glutamate-1-semialdehyde aminotransferase from Bacillus subtilis

    SciTech Connect

    Lv, Xinhuai; Fan, Jun; Ge, Honghua; Gao, Yongxiang; Zhang, Xiao; Teng, Maikun Niu, Liwen

    2006-05-01

    Crystals of glutamate-1-semialdehyde aminotransferase (GSAT) from B. subtilis were obtained and diffraction data were collected to 2.0 Å resolution. 5-Aminolevulinic acid (ALA) is the first committed universal precursor in the tetrapyrrole-biosynthesis pathway. Plants, algae and many other bacteria synthesize ALA from glutamate by a C5 pathway in which the carbon skeleton of glutamate is converted into ALA by a series of enzymes. Glutamate-1-semialdehyde aminotransferase (GSAT) is the last enzyme in this pathway. The gene that codes for GSAT was amplified from the cDNA library of Bacillus subtilis and overexpressed in Escherichia coli strain BL21(DE3). The protein was purified and crystallized. Well diffracting single crystals were obtained by the hanging-drop vapour-diffusion method. Preliminary X-ray diffraction studies yielded excellent diffraction data to a resolution of 2.0 Å.

  16. Purification, crystallization and preliminary X-ray crystallographic analysis of branched-chain aminotransferase from Deinococcus radiodurans

    SciTech Connect

    Chen, Chung-Der; Huang, Tien-Feng; Lin, Chih-Hao; Guan, Hong-Hsiang; Hsieh, Yin-Cheng; Lin, Yi-Hung; Huang, Yen-Chieh; Liu, Ming-Yih; Chang, Wen-Chang; Chen, Chun-Jung

    2007-06-01

    The crystallization of branched-chain aminotransferase from D. radiodurans is described. The branched-chain amino-acid aminotransferase (BCAT), which requires pyridoxal 5′-phosphate (PLP) as a cofactor, is a key enzyme in the biosynthetic pathway of the hydrophobic amino acids leucine, isoleucine and valine. DrBCAT from Deinococcus radiodurans, which has a molecular weight of 40.9 kDa, was crystallized using the hanging-drop vapour-diffusion method. According to X-ray diffraction data to 2.50 Å resolution from a DrBCAT crystal, the crystal belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 56.37, b = 90.70, c = 155.47 Å. Preliminary analysis indicates the presence of two DrBCAT molecules in the asymmetric unit, with a solvent content of 47.52%.

  17. Gyrate atrophy of the choroid and retina with hyperornithinemia: characterization of mutant liver L-ornithine:2-oxoacid aminotransferase kinetics.

    PubMed

    Sipilä, I; Simell, O; O'Donnell, J J

    1981-06-01

    Deficient activity of L-ornithine:2-oxoacid aminotransferase is associated with gyrate atrophy of the choroid and retina with hyperornithinemia, an autosomal recessive disease leading to blindness. Liver tissue from two patients contained trace activity of the enzyme. The Michaelis (Km) value of the mutant enzyme for ornithine was 200 mM, 50-fold higher than normal, but increasing the concentrations of alpha-oxoglutarate and pyridoxal 5'-phosphate to 10 times those giving maximal activity of the normal enzyme had no effect on the mutant enzyme. Substrate inhibition of the mutant could not be demonstrated at 1,000 mM ornithine concentration, whereas ornithine concentrations above 70 mM inhibited the normal enzyme. The data suggest that the abnormal L-ornithine:2-oxoacid aminotransferase in the two patients studied has an altered binding site for ornithine. PMID:7240420

  18. D-Lactate transport and metabolism in rat liver mitochondria.

    PubMed Central

    de Bari, Lidia; Atlante, Anna; Guaragnella, Nicoletta; Principato, Giovanni; Passarella, Salvatore

    2002-01-01

    In the present study we investigated whether isolated rat liver mitochondria can take up and metabolize D-lactate. We found the following: (1) externally added D-lactate causes oxygen uptake by mitochondria [P/O ratio (the ratio of mol of ATP synthesized to mol of oxygen atoms reduced to water during oxidative phosphorylation)=2] and membrane potential (Delta(psi)) generation in processes that are rotenone-insensitive, but inhibited by antimycin A and cyanide, and proton release from coupled mitochondria inhibited by alpha-cyanocinnamate, but not by phenylsuccinate; (2) the activity of the putative flavoprotein (D-lactate dehydrogenase) was detected in inside-out submitochondrial particles, but not in mitochondria and mitoplasts, as it is localized in the matrix phase of the mitochondrial inner membrane; (3) three novel separate translocators exist to mediate D-lactate traffic across the mitochondrial inner membrane: the D-lactate/H(+) symporter, which was investigated by measuring fluorimetrically the rate of endogenous flavin reduction, the D-lactate/oxoacid antiporter (which mediates both the D-lactate/pyruvate and D-lactate/oxaloacetate exchanges) and D-lactate/malate antiporter studied by monitoring photometrically the appearance of the D-lactate counteranions outside mitochondria. The D-lactate translocators, in the light of their different inhibition profiles separate from the monocarboxylate carrier, were found to differ from each other in the V(max) values and in the inhibition and pH profiles and were shown to regulate mitochondrial D-lactate metabolism in vitro. The D-lactate translocators and the D-lactate dehydrogenase could account for the removal of the toxic methylglyoxal from cytosol, as well as for D-lactate-dependent gluconeogenesis. PMID:11955284

  19. Effect of lactation number, year, and season of initiation of lactation on milk yield of cows hormonally induced into lactation and treated with recombinant bovine somatotropin.

    PubMed

    Mellado, M; Antonio-Chirino, E; Meza-Herrera, C; Veliz, F G; Arevalo, J R; Mellado, J; de Santiago, A

    2011-09-01

    Records representing data from 1,500 barren Holstein cows over an 8-yr period from a large commercial dairy farm in northern Mexico were analyzed to determine the effects of lactation number and season and year of initiation of lactation on milk production of cows induced hormonally into lactation and treated with recombinant bovine somatotropin (rbST) throughout lactation. Peak and 305-d milk yields were also assessed as predictors of total milk yield in cows induced into lactation. A significant quadratic relationship was found between 305-d milk yield and number of lactation [7,607±145 and 9,548±181 kg for first- and ≥6-lactation cows, respectively; mean ± standard error of the mean (SEM)] with the highest production occurring in the fifth lactation. Total milk yields of cows with ≤2 lactations were approximately 4,500 kg less than milk yields of adult cows (the overall average ± standard milk yield was 13,544±5,491 kg per lactation and the average lactation length was 454±154 d). Moreover, 305-d milk production was depressed in cows induced into lactation in spring (8,804±153 kg; mean ± SEM) and summer (8,724±163 kg) than in fall (9,079±151 kg) and winter (9,085±143 kg). Partial regression coefficients for 305-d milk yield and peak milk yield indicated an increment of 157 kg of milk per lactation per 1-kg increase in peak milk yield (r(2)=0.69). Neither peak milk yield (r(2)=0.18) nor 305-d milk yield (r(2)=0.29) was accurate for predicting total milk yield per lactation. Year, parity, and season effects had significant influence on milk yield of cows induced into lactation and treated with rbST throughout lactation, and peak milk yield can assist in the prediction of 305-d milk yield but not total milk yield. This study also showed that hormonal induction of lactation in barren high-yielding cows is a reliable, practical, and affordable technique in countries where rbST treatment and prolonged steroid administration of dairy cows are legally

  20. Deciphering the Role of Aspartate and Prephenate Aminotransferase Activities in Plastid Nitrogen Metabolism1[C][W][OPEN

    PubMed Central

    de la Torre, Fernando; El-Azaz, Jorge; Ávila, Concepción; Cánovas, Francisco M.

    2014-01-01

    Chloroplasts and plastids of nonphotosynthetic plant cells contain two aspartate (Asp) aminotransferases: a eukaryotic type (Asp5) and a prokaryotic-type bifunctional enzyme displaying Asp and prephenate aminotransferase activities (PAT). We have identified the entire Asp aminotransferase gene family in Nicotiana benthamiana and isolated and cloned the genes encoding the isoenzymes with plastidic localization: NbAsp5 and NbPAT. Using a virus-induced gene silencing approach, we obtained N. benthamiana plants silenced for NbAsp5 and/or NbPAT. Phenotypic and metabolic analyses were conducted in silenced plants to investigate the specific roles of these enzymes in the biosynthesis of essential amino acids within the plastid. The NbAsp5 silenced plants had no changes in phenotype, exhibiting similar levels of free Asp and glutamate as control plants, but contained diminished levels of asparagine and much higher levels of lysine. In contrast, the suppression of NbPAT led to a severe reduction in growth and strong chlorosis symptoms. NbPAT silenced plants exhibited extremely reduced levels of asparagine and were greatly affected in their phenylalanine metabolism and lignin deposition. Furthermore, NbPAT suppression triggered a transcriptional reprogramming in plastid nitrogen metabolism. Taken together, our results indicate that NbPAT has an overlapping role with NbAsp5 in the biosynthesis of Asp and a key role in the production of phenylalanine for the biosynthesis of phenylpropanoids. The analysis of NbAsp5/NbPAT cosilenced plants highlights the central role of both plastidic aminotransferases in nitrogen metabolism; however, only NbPAT is essential for plant growth and development. PMID:24296073

  1. Titration of Alanine Monitored by NMR Spectroscopy: A Biochemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Waller, Francis J.; And Others

    1977-01-01

    The experiment described here involves simultaneous monitoring of pH and NMR chemical shifts during an aqueous titration of alpha- and beta-alanine. This experiment is designed for use in an undergraduate biochemistry course. (MR)

  2. Best prediction of yields for long lactations.

    PubMed

    Cole, J B; Null, D J; Vanraden, P M

    2009-04-01

    Lactation records of any reasonable length now can be processed with the selection index method known as best prediction (BP). Previous prediction programs were limited to the 305-d standard used since 1935. Best prediction was implemented in 1998 to calculate lactation records in USDA genetic evaluations, replacing the test interval method used since 1969 to calculate lactation records. Best prediction is more complex but also more accurate, particularly when testing is less frequent. Programs were reorganized to output better graphics, give users simpler access to options, and provide additional output, such as BP of daily yields. Test-day data for 6 breeds were extracted from the national dairy database, and lactation lengths were required to be > or =500 d (Ayrshire, Milking Shorthorn) or > or =800 d (all others). Average yield and SD at any day in milk (DIM) were estimated by fitting 3-parameter Wood's curves (milk, fat, protein) and 4-parameter exponential functions (somatic cell score) to means and SD of 15- (< or =300 DIM) and 30-d (>300 DIM) intervals. Correlations among TD yields were estimated using an autoregressive matrix to account for biological changes and an identity matrix to model daily measurement error. Autoregressive parameters (r) were estimated separately for first (r = 0.998) and later parities (r = 0.995). These r values were slightly larger than previous estimates due to the inclusion of the identity matrix. Correlations between traits were modified so that correlations between somatic cell score and other traits may be nonzero. The new lactation curves and correlation functions were validated by extracting TD data from the national database, estimating 305-d yields using the original and new programs, and correlating those results. Daily BP of yield were validated using daily milk weights from on-farm meters in university research herds. Correlations ranged from 0.900 to 0.988 for 305-d milk yield. High correlations ranged from 0.844 to

  3. Mustard bran in lactating dairy cow diets.

    PubMed

    Maiga, H A; Bauer, M L; Dahlen, C R; Badaruddin, M; Scholljegerdes, E J

    2011-06-01

    Two trials using lactating Holstein cows were conducted to evaluate effects of a diet containing oriental mustard bran on dry matter intake (DMI), milk production, milk components, and organoleptic properties. In experiment 1, 34 lactating cows (24 multiparous and 10 primiparous; days in milk ≥ 50 d) were used in a switchback design to determine the lactational response and organoleptic quality of milk when the diet contained 8% oriental mustard bran (MB) versus a control diet (CON). Mustard bran replaced a portion of soybean meal and all the beet pulp in the CON diet. Milk yields were greater for cows fed the MB diet; however, no differences were found in DMI, 3.5% fat- (FCM) or solids-corrected milk. Milk components and components production were not affected by treatment. Milk organoleptic qualities were not affected by diet. In experiment 2, 22 lactating cows (16 multiparous and 6 primiparous; days in milk ≥ 21 d) were assigned randomly within parity to receive MB or CON from wk 4 to 19 postpartum in a randomized complete block design. Cows were fed CON wk 1 to 3 postpartum. The MB diet contained the same ingredients as the CON, except sunflower seed and a portion of soybean meal were replaced with mustard bran. Milk and components data were collected during wk 3 postpartum and used as covariates to adjust treatment means. Intake was greater for cows fed the MB diet; however, daily milk, 3.5% FCM, and solids-corrected milk yields were not different between diets. Milk components and component yields were not affected by treatment. Milk urea concentration was less for cows fed the MB diet. Although cows fed the MB diet had greater DMI, this was not translated into a higher milk 3.5% FCM/DMI production efficiency ratio. During experiment 2, many cows fed MB experienced minor to severe hemolysis with bloody urine. This hemolysis believed to be caused by the S-methyl-cysteine sulfoxide contained in mustard bran could have affected milk production efficiency

  4. Repeated Supramaximal Exercise-Induced Oxidative Stress: Effect of β-Alanine Plus Creatine Supplementation

    PubMed Central

    Belviranli, Muaz; Okudan, Nilsel; Revan, Serkan; Balci, Serdar; Gokbel, Hakki

    2016-01-01

    Background: Carnosine is a dipeptide formed from the β-alanine and histidine amino acids and found in mainly in the brain and muscle, especially fast twitch muscle. Carnosine and creatine has an antioxidant effect and carnosine accounts for about 10% of the muscle's ability to buffer the H+ ions produced by exercise. Objectives: The aim of the study was to investigate the effects of beta alanine and/or creatine supplementation on oxidant and antioxidant status during repeated Wingate tests (WTs). Patients and Methods: Forty four sedentary males participated in the study. Participants performed three 30s WTs with 2 minutes rest between exercise bouts. After the first exercise session, the subjects were assigned to one of four groups: Placebo, Creatine, Beta-alanine and Beta-alanine plus creatine. Participants ingested twice per day for 22 consecutive days, then four times per day for the following 6 days. After the supplementation period the second exercise session was applied. Blood samples were taken before and immediately after the each exercise session for the analysis of oxidative stress and antioxidant markers. Results: Malondialdehyde levels and superoxide dismutase activities were affected by neither supplementation nor exercise. During the pre-supplementation session, protein carbonyl reduced and oxidized glutathione (GSH and GSSG) levels increased immediately after the exercise. However, during the post-supplementation session GSH and GSSG levels increased in beta-alanine and beta-alanine plus creatine groups immediately after the exercise compared to pre-exercise. In addition, during the post-supplementation session total antioxidant capacity increased in beta-alanine group immediately after the exercise. Conclusions: Beta-alanine supplementation has limited antioxidant effect during the repeated WTs. PMID:27217925

  5. Internal bias field in triglycine sulphate crystals with L-, α-alanine grown at negative temperatures

    NASA Astrophysics Data System (ADS)

    Milovidova, S. D.; Rogazinskaya, O. V.; Sidorkin, A. S.; Ionova, E. V.; Kirichenko, A. P.; Bavykin, S. A.

    2010-09-01

    The dielectric and pyroelectric properties of triglycine sulphate (TGS) crystals with L, α-alanine impurities grown at negative temperatures have been investigated. It is shown that a lower impurity concentration (2 mol % in solution) in this temperature range leads to the formation of internal bias fields of the same order of magnitude (˜800 V/cm) as for TGS crystals grown at T ⩽ 50°C but with an L, α-alanine concentration of 20 mol % in solution.

  6. IR spectroscopic signatures of solid glycine and alanine in astrophysical ices

    NASA Astrophysics Data System (ADS)

    Rodriguez-Lazcano, Y.; Maté, B.; Tanarro, I.; Herrero, V.; Escribano, R.

    2012-09-01

    The conversion from solid neutral to zwitterionic glycine (or alanine) is studied using infrared spectroscopy from the point of view of the interactions of this molecule with polar (water) and non-polar (CO2, CH4) surroundings. Such environments could be found on astrophysical matter. Different spectral features are suggested as suitable probes for the presence of glycine (or alanine) in astrophysical media, depending on their form (normal or zwitterionic), temperature, and composition.

  7. The energetics of lactation in cooperatively breeding meerkats Suricata suricatta.

    PubMed

    Scantlebury, M; Russell, A F; McIlrath, G M; Speakman, J R; Clutton-Brock, T H

    2002-10-22

    Species may become obligate cooperative breeders when parents are unable to raise their offspring unassisted. We measured the daily energy expenditure of mothers, helpers and offspring during peak lactation in cooperatively breeding meerkats Suricata suricatta using the doubly labelled water technique. Lactating mothers expended more energy per day than allo-lactating subordinate females, non-lactating females or suckling offspring. Metabolizable energy intakes of lactating mothers were calculated from isotope-based estimates of offspring milk energy intake, and were not significantly different from the previously suggested maximal limit for mammals. Allo-lactating females were the only category of animals that lost weight during the period of study, probably because they spent more time babysitting than non-lactating females. Daily energy expenditure (DEE) of lactating mothers increased with litter size but decreased with the number of helpers. Calculations show that for every 10 helpers, even in the absence of allo-lactators, mothers are able to reduce their DEE during peak lactation by an amount equivalent to the energy cost of one pup. These results indicate that helpers have beneficial energetic consequences for lactating mothers in an obligate cooperatively breeding mammal. PMID:12396490

  8. The energetics of lactation in cooperatively breeding meerkats Suricata suricatta.

    PubMed Central

    Scantlebury, M; Russell, A F; McIlrath, G M; Speakman, J R; Clutton-Brock, T H

    2002-01-01

    Species may become obligate cooperative breeders when parents are unable to raise their offspring unassisted. We measured the daily energy expenditure of mothers, helpers and offspring during peak lactation in cooperatively breeding meerkats Suricata suricatta using the doubly labelled water technique. Lactating mothers expended more energy per day than allo-lactating subordinate females, non-lactating females or suckling offspring. Metabolizable energy intakes of lactating mothers were calculated from isotope-based estimates of offspring milk energy intake, and were not significantly different from the previously suggested maximal limit for mammals. Allo-lactating females were the only category of animals that lost weight during the period of study, probably because they spent more time babysitting than non-lactating females. Daily energy expenditure (DEE) of lactating mothers increased with litter size but decreased with the number of helpers. Calculations show that for every 10 helpers, even in the absence of allo-lactators, mothers are able to reduce their DEE during peak lactation by an amount equivalent to the energy cost of one pup. These results indicate that helpers have beneficial energetic consequences for lactating mothers in an obligate cooperatively breeding mammal. PMID:12396490

  9. The effect of dietary energy source during mid to late lactation on liver triglyceride and lactation performance of dairy cows.

    PubMed

    Vazquez-Añon, M; Bertics, S J; Grummer, R R

    1997-10-01

    Control [1.61 Mcal of net energy for lactation (NEL)/kg of dry matter (DM)], high grain (1.70 Mcal of NEL)/kg of DM), or high fat [1.70 Mcal of NEL/kg of DM with 2.3% tallow (DM basis)] diets were fed to 43 cows (150 +/- 3.1 d in milk) during mid to late lactation to determine effects on performance characteristics, metabolic parameters, or both during mid to late lactation, the dry period, and the first 100 d of the next lactation. All cows received identical diets during the dry period and during early lactation. Increasing the energy density of the diets during mid to late lactation increased DM intake (DMI), plasma nonesterified fatty acid concentration, milk production, and milk protein yield. Compared with the high grain diets, fat supplementation decreased DMI and the percentage of milk protein but increased plasma nonesterified fatty acid concentration without causing elevation of liver triglyceride at the end of mid to late lactation. Increased energy density of the diets did not affect body condition score during mid to late lactation. There were no residual effects for any of the treatments on DMI, lactation performance, or body weight in the subsequent lactation. However, energy supplementation during mid to late lactation increased liver triglyceride content after calving. Compared with high fat diets, high grain diets fed during mid to late lactation increased plasma beta-hydroxy-butyrate concentration in the subsequent lactation. High energy diets fed during mid to late lactation may influence lipid metabolism during the following lactation. PMID:9361222

  10. [Alanine solution as enzyme reaction buffer used in A to O blood group conversion].

    PubMed

    Li, Su-Bo; Zhang, Xue; Zhang, Yin-Ze; Tan, Ying-Xia; Bao, Guo-Qiang; Wang, Ying-Li; Ji, Shou-Ping; Gong, Feng; Gao, Hong-Wei

    2014-06-01

    The aim of this study was to investigate the effect of alanine solution as α-N-acetylgalactosaminidase enzyme reaction buffer on the enzymatic activity of A antigen. The binding ability of α-N-acetylgalactosaminidase with RBC in different reaction buffer such as alanine solution, glycine solution, normal saline (0.9% NaCl), PBS, PCS was detected by Western blot. The results showed that the efficiency of A to O conversion in alanine solution was similar to that in glycine solution, and Western blot confirmed that most of enzymes blinded with RBC in glycine or alanine solution, but few enzymes blinded with RBC in PBS, PCS or normal saline. The evidences indicated that binding of enzyme with RBC was a key element for A to O blood group conversion, while the binding ability of α-N-acetylgalactosaminidase with RBC in alanine or glycine solution was similar. It is concluded that alanine solution can be used as enzyme reaction buffer in A to O blood group conversion. In this buffer, the α-N-acetylgalactosaminidase is closely blinded with RBC and α-N-acetylgalactosaminidase plays efficient enzymatic activity of A antigen. PMID:24989301

  11. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    NASA Astrophysics Data System (ADS)

    Helge Østerås, Bjørn; Olaug Hole, Eli; Rune Olsen, Dag; Malinen, Eirik

    2006-12-01

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 µm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1 15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media.

  12. Lactation Biology Symposium: circadian clocks as mediators of the homeorhetic response to lactation.

    PubMed

    Casey, T M; Plaut, K

    2012-03-01

    The transition from pregnancy to lactation is the most stressful period in the life of a cow. During this transition, homeorhetic adaptations are coordinated across almost every organ and are marked by changes in hormones and metabolism to accommodate the increased energetic demands of lactation. Recent data from our laboratory showed that changes in circadian clocks occur in multiple tissues during the transition period in rats and indicate that the circadian system coordinates changes in the physiology of the dam needed to support lactation. Circadian rhythms coordinate the timing of physiological processes and synchronize these processes with the environment of the animal. Circadian rhythms are generated by molecular circadian clocks located in the hypothalamus (the master clock) and peripherally in every organ of the body. The master clock receives environmental and physiological cues and, in turn, synchronizes internal physiology by coordinating endocrine rhythms and metabolism through peripheral clocks. The effect of the circadian clock on lactation may be inferred by the photoperiod effect on milk production, which is accompanied by coordinated changes in the endocrine system and metabolic capacity of the dam to respond to changes in day length. We have shown that bovine mammary epithelial cells possess a functional clock that can be synchronized by external stimuli, and the expression of the aryl hydrocarbon receptor nuclear translocator-like gene, a positive limb of the core clock, is responsive to prolactin in bovine mammary explants. Others showed that 7% of genes expressed in breasts of lactating women had circadian patterns of expression, and we report that the diurnal variation of composition of bovine milk is associated with changes in expression of mammary core clock genes. Together these studies indicate that the circadian system coordinates the metabolic and hormonal changes needed to initiate and sustain lactation, and we believe that the

  13. Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in Arabidopsis

    PubMed Central

    Pieck, Michael; Yuan, Youxi; Godfrey, Jason; Fisher, Christopher; Zolj, Sanda; Vaughan, Dylan; Thomas, Nicholas; Wu, Connie; Ramos, Julian; Lee, Norman; Normanly, Jennifer; Celenza, John L.

    2015-01-01

    Indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 (Indole Severe Sensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indole-supplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant’s increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways. PMID:26163189

  14. Aspartate aminotransferase activity in experimentally induced asymptomatic vitamin B6 deficiency in chicks.

    PubMed

    Massé, P G; Vuilleumier, J P; Weiser, H

    1991-01-01

    Forty-five male Lohmann chicks were grown up to 6 weeks of age. The experimental diet containing a high protein level (30%) was aimed at increasing the metabolic need for PN. Microbiological analysis on the basal ration revealed a marginal content of 4.7 mumol PN/kg. The vitamin B6 status was assessed at the end of the experiment according to the basal activity of aspartate aminotransferase (AspAT) in plasma and in erythrocytes, and the in vitro stimulated activity with pyridoxal 5'-phosphate (PLP). None of the deficient chicks had any clinical signs attributable to malfunction of the nervous system, and they grew as well as those receiving the control diet. Vitamin B6 deficiency was biochemically confirmed by a significant depression of AspAT activity in plasma (p less than 0.001) and in erythrocytes (p less than 0.01). The addition of PLP in vitro enhanced the catalytic activity of the plasma enzyme, but had negligible effect on the erythrocyte enzyme. The degree of stimulation in vitro of the apoenzyme of AspAT not only depends on the endogenous vitamin B6 content, but also on the basal activity of the enzyme. A 15-day repletion period with a daily oral dose (50 mumol PN) did not result in a complete restoration of the enzyme activity, indicating that the availability of apoenzyme had been curtailed. This experiment demonstrated that chicks fed a high protein corn-soyamin diet with a limited amount of PN but containing Saccharomyces yeast showed no nervous signs or perosis, but significant metabolic disturbances.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2058999

  15. Discovery of novel lysine ɛ-aminotransferase inhibitors: An intriguing potential target for latent tuberculosis.

    PubMed

    Devi, Parthiban Brindha; Sridevi, Jonnalagadda Padma; Kakan, Shruti Singh; Saxena, Shalini; Jeankumar, Variam Ullas; Soni, Vijay; Anantaraju, Hasitha Shilpa; Yogeeswari, Perumal; Sriram, Dharmarajan

    2015-12-01

    Mycobacterium tuberculosis (MTB) has remarkable ability to persist in the human host and causes latent infection in one third of the world population. Currently available tuberculosis (TB) drugs while effective in killing actively growing MTB, is largely ineffective in killing persistent or latent MTB. Lysine-ɛ aminotransferase (LAT) enzyme is reported to be highly up-regulated (41.86 times) in in vitro models of TB designed to mimic the latent stage. Hence inhibition of this MTB LAT seems attractive for developing novel drugs against latent TB. In the present study, crystal structure of the MTB LAT bound to substrate was used as a framework for structure-based design utilizing database compounds to identify novel thiazole derivative as LAT inhibitors. Thirty six compounds were synthesized and evaluated in vitro for their ability to inhibit LAT, in vitro activity against latent MTB, in vivo activity using Mycobacterium marinum infected zebra fish and cytotoxicity as steps toward the derivation of structure-activity relationship (SAR) for lead optimization. Compound 4-methoxy-2-(pyridin-4-yl)thiazole-5-carboxylic acid (24) emerged as the most promising lead with an IC50 of 1.22 ± 0.85 μM against LAT and showed 2.8 log reduction against nutrient starved MTB, with little cytotoxicity at a higher concentration (>50 μM). It also exhibited 1.5 log reduction of M. marinum load in in vivo zebra fish model at 10 mg/kg. PMID:26299907

  16. Tyrosine Aminotransferase Contributes to Benzylisoquinoline Alkaloid Biosynthesis in Opium Poppy1[W

    PubMed Central

    Lee, Eun-Jeong; Facchini, Peter J.

    2011-01-01

    Tyrosine aminotransferase (TyrAT) catalyzes the transamination of l-Tyr and α-ketoglutarate, yielding 4-hydroxyphenylpyruvic acid and l-glutamate. The decarboxylation product of 4-hydroxyphenylpyruvic acid, 4-hydroxyphenylacetaldehyde, is a precursor to a large and diverse group of natural products known collectively as benzylisoquinoline alkaloids (BIAs). We have isolated and characterized a TyrAT cDNA from opium poppy (Papaver somniferum), which remains the only commercial source for several pharmaceutical BIAs, including codeine, morphine, and noscapine. TyrAT belongs to group I pyridoxal 5′-phosphate (PLP)-dependent enzymes wherein Schiff base formation occurs between PLP and a specific Lys residue. The amino acid sequence of TyrAT showed considerable homology to other putative plant TyrATs, although few of these have been functionally characterized. Purified, recombinant TyrAT displayed a molecular mass of approximately 46 kD and a substrate preference for l-Tyr and α-ketoglutarate, with apparent Km values of 1.82 and 0.35 mm, respectively. No specific requirement for PLP was detected in vitro. Liquid chromatography-tandem mass spectrometry confirmed the conversion of l-Tyr to 4-hydroxyphenylpyruvate. TyrAT gene transcripts were most abundant in roots and stems of mature opium poppy plants. Virus-induced gene silencing was used to evaluate the contribution of TyrAT to BIA metabolism in opium poppy. TyrAT transcript levels were reduced by at least 80% in silenced plants compared with controls and showed a moderate reduction in total alkaloid content. The modest correlation between transcript levels and BIA accumulation in opium poppy supports a role for TyrAT in the generation of alkaloid precursors, but it also suggests the occurrence of other sources for 4-hydroxyphenylacetaldehyde. PMID:21949209

  17. Branched-Chain Aminotransferases Control TORC1 Signaling in Saccharomyces cerevisiae

    PubMed Central

    Kingsbury, Joanne M.; Sen, Neelam D.; Cardenas, Maria E.

    2015-01-01

    The conserved target of rapamycin complex 1 (TORC1) integrates nutrient signals to orchestrate cell growth and proliferation. Leucine availability is conveyed to control TORC1 activity via the leu-tRNA synthetase/EGOC-GTPase module in yeast and mammals, but the mechanisms sensing leucine remain only partially understood. We show here that both leucine and its α-ketoacid metabolite, α-ketoisocaproate, effectively activate the yeast TORC1 kinase via both EGOC GTPase-dependent and -independent mechanisms. Leucine and α-ketoisocaproate are interconverted by ubiquitous branched-chain aminotransferases (BCAT), which in yeast are represented by the mitochondrial and cytosolic enzymes Bat1 and Bat2, respectively. BCAT yeast mutants exhibit severely compromised TORC1 activity, which is partially restored by expression of Bat1 active site mutants, implicating both catalytic and structural roles of BCATs in TORC1 control. We find that Bat1 interacts with branched-chain amino acid metabolic enzymes and, in a leucine-dependent fashion, with the tricarboxylic acid (TCA)-cycle enzyme aconitase. BCAT mutation perturbed TCA-cycle intermediate levels, consistent with a TCA-cycle block, and resulted in low ATP levels, activation of AMPK, and TORC1 inhibition. We propose the biosynthetic capacity of BCAT and its role in forming multicomplex metabolons connecting branched-chain amino acids and TCA-cycle metabolism governs TCA-cycle flux to activate TORC1 signaling. Because mammalian mitochondrial BCAT is known to form a supramolecular branched-chain α-keto acid dehydrogenase enzyme complex that links leucine metabolism to the TCA-cycle, these findings establish a precedent for understanding TORC1 signaling in mammals. PMID:26659116

  18. Relaxed Evolution in the Tyrosine Aminotransferase Gene Tat in Old World Fruit Bats (Chiroptera: Pteropodidae)

    PubMed Central

    Shen, Bin; Fang, Tao; Yang, Tianxiao; Jones, Gareth; Irwin, David M.; Zhang, Shuyi

    2014-01-01

    Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid) catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene) is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae) and two New World fruit bats (Phyllostomidae). Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats) formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet. PMID:24824435

  19. Characterization of the branched-chain amino acid aminotransferase enzyme family in tomato.

    PubMed

    Maloney, Gregory S; Kochevenko, Andrej; Tieman, Denise M; Tohge, Takayuki; Krieger, Uri; Zamir, Dani; Taylor, Mark G; Fernie, Alisdair R; Klee, Harry J

    2010-07-01

    Branched-chain amino acids (BCAAs) are synthesized in plants from branched-chain keto acids, but their metabolism is not completely understood. The interface of BCAA metabolism lies with branched-chain aminotransferases (BCAT) that catalyze both the last anabolic step and the first catabolic step. In this study, six BCAT genes from the cultivated tomato (Solanum lycopersicum) were identified and characterized. SlBCAT1, -2, -3, and -4 are expressed in multiple plant tissues, while SlBCAT5 and -6 were undetectable. SlBCAT1 and -2 are located in the mitochondria, SlBCAT3 and -4 are located in chloroplasts, while SlBCAT5 and -6 are located in the cytosol and vacuole, respectively. SlBCAT1, -2, -3, and -4 were able to restore growth of Escherichia coli BCAA auxotrophic cells, but SlBCAT1 and -2 were less effective than SlBCAT3 and -4 in growth restoration. All enzymes were active in the forward (BCAA synthesis) and reverse (branched-chain keto acid synthesis) reactions. SlBCAT3 and -4 exhibited a preference for the forward reaction, while SlBCAT1 and -2 were more active in the reverse reaction. While overexpression of SlBCAT1 or -3 in tomato fruit did not significantly alter amino acid levels, an expression quantitative trait locus on chromosome 3, associated with substantially higher expression of Solanum pennellii BCAT4, did significantly increase BCAA levels. Conversely, antisense-mediated reduction of SlBCAT1 resulted in higher levels of BCAAs. Together, these results support a model in which the mitochondrial SlBCAT1 and -2 function in BCAA catabolism while the chloroplastic SlBCAT3 and -4 function in BCAA synthesis. PMID:20435740

  20. Relaxed evolution in the tyrosine aminotransferase gene tat in old world fruit bats (Chiroptera: Pteropodidae).

    PubMed

    Shen, Bin; Fang, Tao; Yang, Tianxiao; Jones, Gareth; Irwin, David M; Zhang, Shuyi

    2014-01-01

    Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid) catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene) is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae) and two New World fruit bats (Phyllostomidae). Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats) formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet. PMID:24824435

  1. Inhibition of the enzyme, GABA-aminotransferase in human platelets by vigabatrin, a potential antiepileptic drug.

    PubMed Central

    Rimmer, E; Kongola, G; Richens, A

    1988-01-01

    1. The effect of the new antiepileptic drug, vigabatrin (gamma-vinyl GABA), on the platelet enzyme, GABA-aminotransferase (GABA-T) was investigated in volunteers and patients. Platelets GABA-T activity was assayed using a radioenzymic method. 2. Three single oral doses of vigabatrin (1 g, 2 g and 4 g) were given to six healthy male volunteers in an open randomised cross over study and compared with a baseline period preceding the three treatments. 3. Significant inhibition of the platelet GABA-T was produced by treatment with all three doses and a dose-response relationship was demonstrated. The minimum enzyme activities after 1 g, 2 g and 4 g doses were 43%, 30% and 21% respectively compared with the control values. 4. A significant depression of enzyme activity occurred at 30 min after drug administration and the values remained below control values for 72 h post-dose, outlasting the presence of the drug itself in the plasma. 5. Eight patients with chronic refractory epilepsy were treated with vigabatrin for 6 weeks. After taking the 2 g daily dose for 1 week there was a marked reduction in platelet enzyme activity in all subjects but the enzyme inhibition produced by the 3 g dose was not significantly different from that produced by the 2 g dose, even after 4 weeks treatment with the larger dose. The mean enzyme activity was approximately 30% throughout the active treatment period. One week after stopping vigabatrin, the enzyme levels were not significantly different from the baseline values.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3358887

  2. Major Role of NAD-Dependent Lactate Dehydrogenases in Aerobic Lactate Utilization in Lactobacillus plantarum during Early Stationary Phase

    PubMed Central

    Goffin, Philippe; Lorquet, Frédérique; Kleerebezem, Michiel; Hols, Pascal

    2004-01-01

    NAD-independent lactate dehydrogenases are commonly thought to be responsible for lactate utilization during the stationary phase of aerobic growth in Lactobacillus plantarum. To substantiate this view, we constructed single and double knockout mutants for the corresponding genes, loxD and loxL. Lactate-to-acetate conversion was not impaired in these strains, while it was completely blocked in mutants deficient in NAD-dependent lactate dehydrogenase activities, encoded by the ldhD and ldhL genes. We conclude that NAD-dependent but not NAD-independent lactate dehydrogenases are involved in this process. PMID:15375150

  3. The primary pathway for lactate oxidation in Desulfovibrio vulgaris

    PubMed Central

    Vita, Nicolas; Valette, Odile; Brasseur, Gaël; Lignon, Sabrina; Denis, Yann; Ansaldi, Mireille; Dolla, Alain; Pieulle, Laetitia

    2015-01-01

    The ability to respire sulfate linked to lactate oxidation is a key metabolic signature of the Desulfovibrio genus. Lactate oxidation by these incomplete oxidizers generates reductants through lactate dehydrogenase (LDH) and pyruvate-ferredoxin oxidoreductase (PFOR), with the latter catalyzing pyruvate conversion into acetyl-CoA. Acetyl-CoA is the source of substrate-level phosphorylation through the production of ATP. Here, we show that these crucial steps are performed by enzymes encoded by a nonacistronic transcriptional unit named now as operon luo (for lactate utilization operon). Using a combination of genetic and biochemical techniques, we assigned a physiological role to the operon genes DVU3027-28 and DVU3032-33. The growth of mutant Δ26-28 was highly disrupted on D-lactate, whereas the growth of mutant Δ32-33 was slower on L-lactate, which could be related to a decrease in the activity of D-lactate or L-lactate oxidase in the corresponding mutants. The DVU3027-28 and DVU3032-33 genes thus encode functional D-LDH and L-LDH enzymes, respectively. Scanning of the genome for lactate utilization revealed several lactate permease and dehydrogenase homologs. However, transcriptional compensation was not observed in any of the mutants except for lactate permease. Although there is a high degree of redundancy for lactate oxidase, it is not functionally efficient in LDH mutants. This result could be related to the identification of several operon enzymes, including LDHs, in the PFOR activity bands, suggesting the occurrence of a lactate-oxidizing supermolecular structure that can optimize the performance of lactate utilization in Desulfovibrio species. PMID:26167158

  4. Chronic pain management in pregnancy and lactation.

    PubMed

    Coluzzi, F; Valensise, H; Sacco, M; Allegri, M

    2014-02-01

    During pregnancy most of women will experience some kind of pain, either as a result of a pre-existing condition (low back pain, headache, fibromyalgia, and rheumatoid arthritis) or as a direct consequence of pregnancy (weight gain, postural changes, pelvic floor dysfunction, hormonal factors). However, chronic pain management during pregnancy and lactation remains a challenge for clinicians and pregnant women are at risk of undertreatment for painful conditions, because of fear about use of drugs during pregnancy. Few analgesic drugs have been demonstrated to be absolutely contraindicated during pregnancy and breastfeeding, but studies in pregnant women are not available for most of pain medications. The aim of this paper is to review the safety profile in pregnancy or lactation of the commonly prescribed pain medications and non-pharmacological treatments. In addition to the conventional classifications from the Food and Drug Administration and the American Academy of Paediatrics, authors analyzed the currently available clinical data from literature. PMID:23857445

  5. Lipid Transport in the Lactating Mammary Gland

    PubMed Central

    McManaman, James L.

    2015-01-01

    Mammalian cells depend on phospholipid (PL) and fatty acid (FA) transport to maintain membrane structure and organization, and to fuel and regulate cellular functions. In mammary glands of lactating animals, copious milk secretion, including large quantities of lipid in some species, requires adaptation and integration of PL and FA synthesis and transport processes to meet secretion demands. At present few details exist about how these processes are regulated within the mammary gland. However, recent advances in our understanding of the structural and molecular biology of membrane systems and cellular lipid trafficking provide insights into the mechanisms underlying the regulation and integration of PL and FA transport processes the lactating mammary gland. This review discusses the PL and FA transport processes required to maintain the structural integrity and organization of the mammary gland and support its secretory functions within the context of current molecular and cellular models of their regulation. PMID:24567110

  6. Spectrophotometric determination of ethacridine lactate in infusion

    PubMed Central

    Jain, Pritam S.; Surana, S. J.

    2011-01-01

    Aim: A simple, rapid, selective, accurate, and precise UV spectrophotometric method has been developed for the estimation of ethacridine lactate from bulk and pharmaceutical formulation. Materials and Methods: Appropriate aliquot portions of stock standard solution of ethacridine lactate were transferred into five separate 10 ml volumetric flasks, and the volume was adjusted to the mark with double distilled water to obtain concentrations of 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 μg/ml. The λmax of ethacridine lactate in double distill water was found to be 271 nm with an apparent molar absorptivity of 59.781 × 103 l/mol cm. The drug follows linearity in the concentration range 2–12 μg/ml with a correlation coefficient value of 0.998. Results: The proposed method was applied to pharmaceutical formulation and % amount of drug estimated 99.71% was found to be in good agreement with the label claim. The accuracy of the method was checked by recovery experiment performed at three different levels, i.e., 80%, 100%, and 120%. The % recovery was found to be in the range 99.26–100.25%. The low values of % RSD are indicative of the accuracy and reproducibility of the method. The precision of the method was studied as intraday, interday variations and repeatability. The % RSD value less than 2 indicates that the method is precise. Ruggedness of the proposed method was studied with the help of two analysts. Conclusion: The results indicated that the method could be used for the routine estimation of ethacridine lactate from tablet formulations. PMID:23781454

  7. Peafowl lactate dehydrogenase: problem of isoenzyme identification.

    PubMed

    Rose, R G; Wilson, A C

    1966-09-16

    Peafowl, like other vertebrates, contain multiple forms of lactate dehydrogenase. The electrophoretic properties of the peafowl isoenzymes are unusual in that the isoenzyme from heart tissue can be either more or less anodic than that of muscle, depending on the pH. This finding focuses attention on the problem of isoenzyme identification. It is suggested that isoenzymes be identified on the basis of properties that are chemically and biologically more significant than electrophoretic mobility. PMID:5917779

  8. Effects of 28-Day Beta-Alanine Supplementation on Isokinetic Exercise Performance and Body Composition in Female Masters Athletes.

    PubMed

    Glenn, Jordan M; Gray, Michelle; Stewart, Rodger W; Moyen, Nicole E; Kavouras, Stavros A; DiBrezzo, Ro; Turner, Ronna; Baum, Jamie I; Stone, Matthew S

    2016-01-01

    Beta-alanine (BA) supplementation increases exercise performance due to increases in the intramuscular lactate buffer, carnosine. Females are more sensitive to these increases and results are further pronounced in trained individuals. Baseline intramuscular carnosine levels also naturally decrease with age; therefore, trained older females may experience augmented benefits from BA supplementation. However, the ability of BA to increase lower-body isokinetic strength (ISO) in female masters athletes (MA) is unknown. The purpose of this study was to examine the longitudinal effects of BA supplementation on ISO, handgrip strength (HG), and body composition in female MA cyclists. Twenty-two subjects participated in this double-blind randomized study. Subjects were randomized into 2 groups (placebo [PLA] = 8 g dextrose; BA = 800 mg + 8 g dextrose) and supplemented 4 times per day for 28 days. ISO, HG, and body composition were evaluated at baseline and at the same day/time each week over the 28-day intervention. No differences existed between groups at baseline or at the 7, 14, and 21 days time points for any variables (p > 0.05). When evaluating ISO (isokinetic) after 28 days, total work performed during the final third of the assessment (24.0 vs. -16.8% change) in flexion and average peak torque (5.4 vs. 2.9% change) in extension were significantly increased from baseline in BA compared with PLA (p ≤ 0.05). No differences existed for HG or body composition after supplementation. Twenty-eight days of BA supplementation increased peak torque and work completed, indicating BA improves lower-body exercise performance in female MA. PMID:26110349

  9. Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels.

    PubMed

    Andrus, Liam P; Unruh, Rachel; Wisniewski, Natalie A; McShane, Michael J

    2015-01-01

    An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate) (pHEMA) and two copolymers of pHEMA and poly(acrylamide) (pAam). Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial "break-in" period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors. PMID:26198251

  10. Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels

    PubMed Central

    Andrus, Liam P.; Unruh, Rachel; Wisniewski, Natalie A.; McShane, Michael J.

    2015-01-01

    An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate) (pHEMA) and two copolymers of pHEMA and poly(acrylamide) (pAam). Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial “break-in” period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors. PMID:26198251

  11. Increased Brain Lactate Concentrations Without Increased Lactate Oxidation During Hypoglycemia in Type 1 Diabetic Individuals

    PubMed Central

    De Feyter, Henk M.; Mason, Graeme F.; Shulman, Gerald I.; Rothman, Douglas L.; Petersen, Kitt Falk

    2013-01-01

    Previous studies have reported that brain metabolism of acetate is increased more than twofold during hypoglycemia in type 1 diabetic (T1D) subjects with hypoglycemia unawareness. These data support the hypothesis that upregulation of blood-brain barrier monocarboxylic acid (MCA) transport may contribute to the maintenance of brain energetics during hypoglycemia in subjects with hypoglycemia unawareness. Plasma lactate concentrations are ∼10-fold higher than acetate concentrations, making lactate the most likely alternative MCA as brain fuel. We therefore examined transport of [3-13C]lactate across the blood-brain barrier and its metabolism in the brains of T1D patients and nondiabetic control subjects during a hypoglycemic clamp using 13C magnetic resonance spectroscopy. Brain lactate concentrations were more than fivefold higher (P < 0.05) during hypoglycemia in the T1D subjects compared with the control subjects. Surprisingly, we observed no increase in the oxidation of blood-borne lactate in the T1D subjects, as reflected by similar 13C fractional enrichments in brain glutamate and glutamine. Taken together, these data suggest that in addition to increased MCA transport at the blood-brain barrier, there may be additional metabolic adaptations that contribute to hypoglycemia unawareness in patients with T1D. PMID:23715622

  12. Evidence for the generation of transaminase inhibitor(s) during ethanol metabolism by rat liver homogenates: a potential mechanism for alcohol toxicity.

    PubMed

    Solomon, L R

    1987-08-01

    Since ethanol consumption decreases hepatic aminotransferase activities in vivo, mechanisms of ethanol-mediated transaminase inhibition were explored in vitro using mitochondria-depleted rat liver homogenates. When homogenates were incubated at 37 degrees with 50 mM ethanol for 1 hr, alanine aminotransferase decreased by 20%, while aspartate aminotransferase was unchanged. After 2 hr, aspartate aminotransferase decreased by 20% and by 3 hr, alanine and aspartate aminotransferases were decreased by 31 and 23%, respectively. Levels of acetaldehyde generated during ethanol oxidation were 525 +/- 47 microM at 1 hr, 855 +/- 14 microM at 2 hr, and 1293 +/- 140 microM at 3 hr. Although inhibition of alcohol oxidation with methylpyrazole or cyanide markedly decreased ethanol-mediated transaminase inhibition, neither incubation with acetate nor generation of reducing equivalents by oxidation of lactate, malate, xylitol, or sorbitol altered the activity of either enzyme. However, semicarbazide, an aldehyde scavenger, prevented inhibition of both aminotransferases by ethanol. Moreover, incubation with 5 mM acetaldehyde for 1 hr inhibited alanine and aspartate aminotransferases by 36 and 26%, respectively. Cyanamide, an aldehyde dehydrogenase inhibitor, had little effect on ethanol-mediated transaminase inhibition. Thus, metabolism of ethanol by rat liver homogenates produces transaminase inhibition similar to that described in vivo and this effect requires acetaldehyde generation but not acetaldehyde oxidation. Since addition of pyridoxal 5'-phosphate to assay mixes did not reverse ethanol effects, aminotransferase inhibition does not result from displacement of vitamin B6 coenzymes. PMID:3663401

  13. Extended lactation in dairy cows: effects of milking frequency, calving season and nutrition on lactation persistency and milk quality.

    PubMed

    Sorensen, Annette; Muir, D Donald; Knight, Christopher H

    2008-02-01

    Twelve spring-calving and twelve winter-calving cows were managed for extended lactation cycles of 18-months duration, with the former group then completing a second extended lactation. Half of the cows were fed according to standard management practice for the herd; the other half received supplementary concentrate from week 9 of lactation onwards. Commencing at the same time, half of the udder of each cow was subjected to increased milking frequency (thrice daily rather than twice daily). Lactation persistency (and hence total milk yield) was significantly increased by frequent milking. Winter calving cows and supplemented cows also exhibited better persistency, but this was only evident up until the point of re-breeding, at around lactation week 33. Milk composition was measured in the spring-calving cows in both their first and second extended lactations. Composition altered during the course of the lactation, protein and fat percentages increasing and lactose percentage decreasing, irrespective of treatment. The quality of the milk for processing into cheese, fermented products, heat-treated products and cream liqueurs was assessed by calculation of casein number (casein protein as a proportion of total protein). Processing quality declined across the course of lactation in those groups that showed poor persistency but not in those that maintained a persistent lactation. Milk hygienic quality (somatic cell counts) showed parallel changes. Body condition score increased during the course of lactation but was not affected by supplementation; none of the cows became excessively fat. All cows remained healthy throughout the extended lactations and the majority (33/36) re-bred successfully. By demonstrating that lactation persistency is plastic and can be improved by simple management interventions, the results lend support to the economic arguments in favour of extended lactation cycles. The likely welfare benefits of extended lactation are also discussed. PMID

  14. Lactate Produced by Glycogenolysis in Astrocytes Regulates Memory Processing

    PubMed Central

    Newman, Lori A.; Korol, Donna L.; Gold, Paul E.

    2011-01-01

    When administered either systemically or centrally, glucose is a potent enhancer of memory processes. Measures of glucose levels in extracellular fluid in the rat hippocampus during memory tests reveal that these levels are dynamic, decreasing in response to memory tasks and loads; exogenous glucose blocks these decreases and enhances memory. The present experiments test the hypothesis that glucose enhancement of memory is mediated by glycogen storage and then metabolism to lactate in astrocytes, which provide lactate to neurons as an energy substrate. Sensitive bioprobes were used to measure brain glucose and lactate levels in 1-sec samples. Extracellular glucose decreased and lactate increased while rats performed a spatial working memory task. Intrahippocampal infusions of lactate enhanced memory in this task. In addition, pharmacological inhibition of astrocytic glycogenolysis impaired memory and this impairment was reversed by administration of lactate or glucose, both of which can provide lactate to neurons in the absence of glycogenolysis. Pharmacological block of the monocarboxylate transporter responsible for lactate uptake into neurons also impaired memory and this impairment was not reversed by either glucose or lactate. These findings support the view that astrocytes regulate memory formation by controlling the provision of lactate to support neuronal functions. PMID:22180782

  15. Brain lactate metabolism: the discoveries and the controversies

    PubMed Central

    Dienel, Gerald A

    2012-01-01

    Potential roles for lactate in the energetics of brain activation have changed radically during the past three decades, shifting from waste product to supplemental fuel and signaling molecule. Current models for lactate transport and metabolism involving cellular responses to excitatory neurotransmission are highly debated, owing, in part, to discordant results obtained in different experimental systems and conditions. Major conclusions drawn from tabular data summarizing results obtained in many laboratories are as follows: Glutamate-stimulated glycolysis is not an inherent property of all astrocyte cultures. Synaptosomes from the adult brain and many preparations of cultured neurons have high capacities to increase glucose transport, glycolysis, and glucose-supported respiration, and pathway rates are stimulated by glutamate and compounds that enhance metabolic demand. Lactate accumulation in activated tissue is a minor fraction of glucose metabolized and does not reflect pathway fluxes. Brain activation in subjects with low plasma lactate causes outward, brain-to-blood lactate gradients, and lactate is quickly released in substantial amounts. Lactate utilization by the adult brain increases during lactate infusions and strenuous exercise that markedly increase blood lactate levels. Lactate can be an ‘opportunistic', glucose-sparing substrate when present in high amounts, but most evidence supports glucose as the major fuel for normal, activated brain. PMID:22186669

  16. Intestinal calcium absorption of women during lactation and after weaning.

    PubMed

    Kalkwarf, H J; Specker, B L; Heubi, J E; Vieira, N E; Yergey, A L

    1996-04-01

    We investigated whether intestinal calcium absorption and serum 1,25-dihydroxycholecalciferol (calcitriol) concentrations are higher in women during lactation and after weaning to compensate for calcium lost in breast milk. Measurements were obtained at 4.6 mo postpartum in 24 lactating women and 24 nonlactating women, at 9.6 mo postpartum in 24 lactating women (2.6 mo after complete weaning) and 24 nonlactating women. One-half of the women in each group were randomly assigned to receive 1 g supplemental Ca/d as calcium carbonate. Fractional calcium absorption was measured by using stable isotopic tracers 42Ca and 44Ca. Fractional absorption was 0.32+/-0.02 (+/-SEM) in both lactating and nonlactating women, but was higher in lactating women after weaning (0.37+/-0.02) compared with nonlactating postpartum control subjects (0.31+/-0.02). These effects were independent of calcium intake. Changes in serum calcitriol paralleled changes in fractional absorption. There were no differences in calcitriol concentrations between lactating and nonlactating women, but calcitriol was greater in women after weaning compared with postpartum control subjects. Lactating women who had resumed menses had higher fractional absorption and serum calcitriol than did lactating women who had not. Serum calcium and phosphorus concentrations were greater in lactating compared with nonlactating women; there were no differences between groups after weaning. We conclude that lactation stimulates increases in fractional calcium absorption and serum calcitriol, but the responses are only apparent after weaning or the resumption of menses. PMID:8599316

  17. Glucose and Alanine Metabolism in Children with Maple Syrup Urine Disease

    PubMed Central

    Haymond, Morey W.; Ben-Galim, Ehud; Strobel, Karen E.

    1978-01-01

    In vitro studies have suggested that catabolism of branched chain amino acids is linked with alanine and glutamine formed in, and released from, muscle. To explore this possibility in vivo, static and kinetic studies were performed in three patients with classical, and one patient with partial, branched chain α-ketoacid decarboxylase deficiency (maple syrup urine disease, MSUD) and compared to similar studies in eight age-matched controls. The subjects underwent a 24-30-h fast, and a glucose-alanine flux study using stable isotopes. Basal plasma leucine concentrations were elevated (P <0.001) in patients with MSUD (1,140±125 μM vs. 155±18 μM in controls); and in contrast to the controls, branched chain amino acid concentrations in plasma increased during the fast in the MSUD patients. Basal plasma alanine concentrations were lower (P <0.01) in patients with classical MSUD (153±8 μM vs. 495±27 μM in controls). This discrepancy was maintained throughout the fast despite a decrease in alanine concentrations in both groups. Plasma alanine and leucine concentrations in the patient with partial MSUD were intermediate between those of the controls and the subjects with the classical form of the disease. Circulating ketone bodies and glucoregulatory hormones concentrations were similar in the MSUD and normal subjects during the fast. Alanine flux rates in two patients with classical MSUD (3.76 and 4.00 μmol/Kg per min) and the patient with partial MSUD (5.76 μmol/Kg per min) were clearly lower than those of the controls (11.72±2.53 [SD] μmol/Kg per min). After short-term starvation, glucose flux and fasting concentrations were similar in the MSUD patients and normal subjects. These data indicate that branched chain amino acid catabolism is an important rate limiting event for alanine production in vivo. PMID:670400

  18. Exchange interactions and magnetic dimension in Cu(L-alanine)2

    NASA Astrophysics Data System (ADS)

    Calvo, R.; Passeggi, M. C. G.; Novak, M. A.; Symko, O. G.; Oseroff, S. B.; Nascimento, O. R.; Terrile, M. C.

    1991-01-01

    A study of the magnetic properties of the copper (II) complex of the amino acid l-alanine [Cu(l-alanine)2] is reported. The susceptibility of a powder sample has been measured between 0.013 and 240 K. A linear-spin-chain model with antiferromagnetic exchange coupling J=-0.52 K fits well the susceptibility data above 0.3 K. Room-temperature electron paramagnetic resonance (EPR) spectra of single crystals of Cu(l-alanine)2 at 9 and 35 GHz show a single, exchange-narrowed resonance. The g tensor, with principal values g1=2.0554+/-0.0005, g2=2.1064+/-0.0005, and g3=2.2056+/-0.0005, reflects the crystal structure of Cu(l-alanine)2 and the electronic properties of the copper ions. The observed angular variation of the linewidth is attributed to the magnetic interactions, narrowed by the exchange coupling between copper ions, and shows a contribution characteristic of the dipole-dipole interaction in a spin system with a predominant two-dimensional spin dynamics. Considering the exchange-collapsed resonance corresponding to the two lattice sites for copper in Cu(l-alanine)2, we evaluate an exchange constant ||J(AB1)||=0.47 K between nonequivalent copper neighbors in a spin chain, similar to the value obtained from the susceptibility data. The one-dimensional magnetic behavior suggested by the susceptibility data in Cu(l-alanine)2, where the metal ions are distributed in layers, is explained by proposing that carboxylate bridges provide electronic paths for superexchange interactions between coppers. Considering the characteristics of the molecular structure of Cu(l-alanine)2, the layers seem to be magnetically split off into one-dimensional zigzag ribbons. The apparent disagreement between the one-dimensional behavior suggested by the susceptibility data and the two-dimensional behavior of the spin dynamics suggested by the EPR linewidth is analyzed.

  19. FTIR spectra and conformational structure of deutero-β-alanine isolated in argon matrices

    NASA Astrophysics Data System (ADS)

    Stepanian, Stepan G.; Ivanov, Alexander Yu; Adamowicz, Ludwik

    2016-02-01

    Low temperature FTIR spectra of β-alanine-d3 isolated in argon matrices are used to determine the conformational composition of this compound. UV irradiation of the matrix samples is found to change the relative populations of the β-alanine-d3 conformers. The populations of conformers I and II with an Nsbnd D⋯O intramolecular H-bond decrease after the UV irradiation while the populations of conformer V with an N⋯Dsbnd O H-bond and conformer IV which has no intramolecular H-bonds increase. This behavior of the β-alanine-d3 conformers are used to separate the bands of the different conformers. The analysis of the experimental FTIR spectra is based on the calculated harmonic B3LYP/6-311++G(df,pd) frequencies and on the MP2/aug-cc-pVDZ frequencies calculated with a method that includes anharmonic effects. Polynomial scaling of the calculated frequencies is used to achieve better agreement with the experimental data. The observation of the wide band of the OD stretching vibration at 2201 cm-1 is a direct evidence of the presence of the β-alanine-d3 conformer V in the Ar matrix. In total ten bands of conformer V are detected. The influence of the matrix environment on the structures and the IR spectra of the β-alanine and β-alanine-d3 conformers is investigated. This involves performing calculations of the β-alanine conformers embedded in argon clusters containing from 163 to 166 argon atoms using the M06-2X and B3LYP(GD3BJ) density-functional methods. Good agreement between the calculated and the experimental matrix splitting is demonstrated.

  20. Ingesting a preworkout supplement containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days is both safe and efficacious in recreationally active men.

    PubMed

    Kendall, Kristina L; Moon, Jordan R; Fairman, Ciaran M; Spradley, Brandon D; Tai, Chih-Yin; Falcone, Paul H; Carson, Laura R; Mosman, Matt M; Joy, Jordan M; Kim, Michael P; Serrano, Eric R; Esposito, Enrico N

    2014-05-01

    The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days. Resting heart rate and BP, body composition, and fasting blood samples were collected before and after supplementation. Aerobic capacity as well as muscular strength and endurance were also measured. Significant (P < .05) main effects for time were observed for resting heart rate (presupplementation, 67.59 ± 7.90 beats per minute; postsupplementation, 66.18 ± 7.63 beats per minute), systolic BP (presupplementation, 122.41 ± 11.25 mm Hg; postsupplementation, 118.35 ± 11.58 mm Hg), blood urea nitrogen (presupplementation, 13.12 ± 2.55 mg/dL; postsupplementation, 15.24 ± 4.47 mg/dL), aspartate aminotransferase (presupplementation, 34.29 ± 16.48 IU/L; postsupplementation, 24.76 ± 4.71 IU/L), and alanine aminotransferase (presupplementation, 32.76 ± 19.72 IU/L; postsupplementation, 24.88 ± 9.68 IU/L). Significant main effects for time were observed for body fat percentage (presupplementation, 15.55% ± 5.79%; postsupplementation, 14.21% ± 5.38%; P = .004) and fat-free mass (presupplementation, 70.80 ± 9.21 kg; postsupplementation, 71.98 ± 9.27 kg; P = .006). A significant decrease in maximal oxygen consumption (presupplementation, 47.28 ± 2.69 mL/kg per minute; postsupplementation, 45.60 ± 2.81 mL/kg per minute) and a significant increase in percentage of

  1. NEUROENDOCRINE ACTIONS AND REGULATION OF HYPOTHALAMIC NEUROPEPTIDE Y DURING LACTATION

    PubMed Central

    Crowley, W,R.; Ramoz, G.; Torto, R.; Keefe, K.A.; Wang, J. J.; Kalra, S. P.

    2007-01-01

    The expression of neuropeptide Y (NPY) and its co-messenger, agouti-related peptide (AgRP), in arcuate neurons of the hypothalamus is increased during lactation in rats. Our research has been addressing the questions of the physiological actions of these peptides during lactation and the physiological signals associated with lactation that result in increased expression of their genes. Our studies indicate that NPY and AgRP exert pleiotropic actions during lactation that help integrate neuroendocrine regulation of energy balance with controls over anterior and posterior pituitary hormone secretion. Further, reciprocal signaling to the NPY/AgRP system by leptin and ghrelin is responsible for the changes in expression of these hypothalamic peptides in lactating animals, and thus, may contribute to regulation of food intake and the various neuroendocrine adaptations of lactation. PMID:17241697

  2. Bacterial contamination of commercially available ethacridine lactate (acrinol) products.

    PubMed

    Oie, S; Kamiya, A

    1996-09-01

    Bacterial contamination of commercially available ethacridine lactate (acrinol) solutions and cotton gauze soaked in ethacridine lactate solution was investigated. Of 56 samples from ethacridine lactate solutions (eight products, seven manufacturers), seven samples (12.5%) of two products (two manufacturers) were contaminated with 10(1)-10(4) colony forming units (cfu)/mL of Burkholderia pickettii. Of 67 samples obtained from gauze soaked in ethacridine lactate solution (seven products, seven manufacturers), 41 (61.2%) of six products (six manufacturers) were contaminated with 10(2)-10(6) cfu/mL of bacteria. The major bacteria detected were Burkholderia cepacia and Burkholderia pickettii. This relatively high incidence of bacterial contamination in commercially available cotton gauze soaked in ethacridine lactate solution may be due to the presence of gauze in ethacridine lactate solution. PMID:8880550

  3. Quantitative analysis of intermediary metabolism in hepatocytes incubated in the presence and absence of glucagon with a substrate mixture containing glucose, ribose, fructose, alanine and acetate.

    PubMed Central

    Rabkin, M; Blum, J J

    1985-01-01

    Hepatocytes were isolated from the livers of fed rats and incubated, in the presence and absence of 100 nM-glucagon, with a substrate mixture containing glucose (10 mM), fructose (4 mM), alanine (3.5 mM), acetate (1.25 mM), and ribose (1 mM). In any given incubation one substrate was labelled with 14C. Incorporation of 14C into glucose, glycogen, CO2, lactate, alanine, glutamate, lipid glycerol and fatty acids was measured after 20 and 40 min of incubation under quasi-steady-state conditions [Borowitz, Stein & Blum (1977) J. Biol. Chem. 252, 1589-1605]. These data and the measured O2 consumption were analysed with the aid of a structural metabolic model incorporating all reactions of the glycolytic, gluconeogenic, and pentose phosphate pathways, and associated mitochondrial and cytosolic reactions. A considerable excess of experimental measurements over independent flux parameters and a number of independent measurements of changes in metabolite concentrations allowed for a stringent test of the model. A satisfactory fit to the data was obtained for each condition. Significant findings included: control cells were glycogenic and glucagon-treated cells glycogenolytic during the second interval; an ordered (last in, first out) model of glycogen degradation [Devos & Hers (1979) Eur. J. Biochem. 99, 161-167] was required in order to fit the experimental data; the pentose shunt contributed approx. 15% of the carbon for gluconeogenesis in both control and glucagon-treated cells; net flux through the lower Embden-Meyerhof pathway was in the glycolytic direction except during the 20-40 min interval in glucagon-treated cells; the increased gluconeogenesis in response to glucagon was correlated with a decreased pyruvate kinase flux and lactate output; fluxes through pyruvate kinase, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase were not coordinately controlled; Krebs cycle activity did not change with glucagon treatment; flux through the malic enzyme was

  4. Purification and characterization of alanine dehydrogenase from a cyanobacterium, Phormidium lapideum.

    PubMed

    Sawa, Y; Tani, M; Murata, K; Shibata, H; Ochiai, H

    1994-11-01

    Alanine dehydrogenase (AlaDH) was purified to homogeneity from cell-free extracts of a non-N2-fixing filamentous cyanobacterium, Phormidium lapideum. The molecular mass of the native enzyme was 240 kDa, and SDS-PAGE revealed a minimum molecular mass of 41 kDa, suggesting a six-subunit structure. The NH2 terminal amino acid residues of the purified AlaDH revealed marked similarity with that of other AlaDHs. The enzyme was highly specific for L-alanine and NAD+, but showed relatively low amino-acceptor specificity. The pH optimum was 8.4 for reductive amination of pyruvate and 9.2 for oxidative deamination of L-alanine. The Km values were 5.0 mM for L-alanine and 0.04 mM for NAD+, 0.33 mM for pyruvate, 60.6 mM for NH4+ (pH 8.7), and 0.02 mM for NADH. Various L-amino acids including alanine, serine, threonine, and aromatic amino acids, inhibited the aminating reaction. The enzyme was inactivated upon incubation with pyridoxal 5'-phosphate (PLP) followed by reduction with sodium borohydride. The copresence of NADH and pyruvate largely protected the enzyme against the inactivation by PLP. PMID:7896761

  5. Role of Alanine Dehydrogenase of Mycobacterium tuberculosis during Recovery from Hypoxic Nonreplicating Persistence

    PubMed Central

    Giffin, Michelle M.; Shi, Lanbo; Gennaro, Maria L.; Sohaskey, Charles D.

    2016-01-01

    Mycobacterium tuberculosis can maintain a nonreplicating persistent state in the host for decades, but must maintain the ability to efficiently reactivate and produce active disease to survive and spread in a population. Among the enzymes expressed during this dormancy is alanine dehydrogenase, which converts pyruvate to alanine, and glyoxylate to glycine concurrent with the oxidation of NADH to NAD. It is involved in the metabolic remodeling of M. tuberculosis through its possible interactions with both the glyoxylate and methylcitrate cycle. Both mRNA levels and enzymatic activities of isocitrate lyase, the first enzyme of the glyoxylate cycle, and alanine dehydrogenase increased during entry into nonreplicating persistence, while the gene and activity for the second enzyme of the glyoxylate cycle, malate synthase were not. This could suggest a shift in carbon flow away from the glyoxylate cycle and instead through alanine dehydrogenase. Expression of ald was also induced in vitro by other persistence-inducing stresses such as nitric oxide, and was expressed at high levels in vivo during the initial lung infection in mice. Enzyme activity was maintained during extended hypoxia even after transcription levels decreased. An ald knockout mutant of M. tuberculosis showed no reduction in anaerobic survival in vitro, but resulted in a significant lag in the resumption of growth after reoxygenation. During reactivation the ald mutant had an altered NADH/NAD ratio, and alanine dehydrogenase is proposed to maintain the optimal NADH/NAD ratio during anaerobiosis in preparation of eventual regrowth, and during the initial response during reoxygenation. PMID:27203084

  6. Role of Alanine Dehydrogenase of Mycobacterium tuberculosis during Recovery from Hypoxic Nonreplicating Persistence.

    PubMed

    Giffin, Michelle M; Shi, Lanbo; Gennaro, Maria L; Sohaskey, Charles D

    2016-01-01

    Mycobacterium tuberculosis can maintain a nonreplicating persistent state in the host for decades, but must maintain the ability to efficiently reactivate and produce active disease to survive and spread in a population. Among the enzymes expressed during this dormancy is alanine dehydrogenase, which converts pyruvate to alanine, and glyoxylate to glycine concurrent with the oxidation of NADH to NAD. It is involved in the metabolic remodeling of M. tuberculosis through its possible interactions with both the glyoxylate and methylcitrate cycle. Both mRNA levels and enzymatic activities of isocitrate lyase, the first enzyme of the glyoxylate cycle, and alanine dehydrogenase increased during entry into nonreplicating persistence, while the gene and activity for the second enzyme of the glyoxylate cycle, malate synthase were not. This could suggest a shift in carbon flow away from the glyoxylate cycle and instead through alanine dehydrogenase. Expression of ald was also induced in vitro by other persistence-inducing stresses such as nitric oxide, and was expressed at high levels in vivo during the initial lung infection in mice. Enzyme activity was maintained during extended hypoxia even after transcription levels decreased. An ald knockout mutant of M. tuberculosis showed no reduction in anaerobic survival in vitro, but resulted in a significant lag in the resumption of growth after reoxygenation. During reactivation the ald mutant had an altered NADH/NAD ratio, and alanine dehydrogenase is proposed to maintain the optimal NADH/NAD ratio during anaerobiosis in preparation of eventual regrowth, and during the initial response during reoxygenation. PMID:27203084

  7. L-alanine in a droplet of water: a density-functional molecular dynamics study.

    PubMed

    Degtyarenko, Ivan M; Jalkanen, Karl J; Gurtovenko, Andrey A; Nieminen, Risto M

    2007-04-26

    We report the results of a Born-Oppenheimer molecular dynamics study on an L-alanine amino acid in neutral aqueous solution. The whole system, the L-alanine zwitterion and 50 water molecules, was treated quantum mechanically. We found that the hydrophobic side chain (R = CH3) defines the trajectory path of the molecule. Initially fully hydrated in an isolated droplet of water, the amino acid moves to the droplet's surface, exposing its hydrophobic methyl group and alpha-hydrogen out of the water. The structure of an L-alanine with the methyl group exposed to the water surface was found to be energetically favorable compared to a fully hydrated molecule. The dynamic behavior of the system suggests that the first hydration shell of the amino acid is localized around carboxylate (CO2-) and ammonium (NH3+) functional groups; it is highly ordered and quite rigid. In contrast, the hydration shell around the side chain is much less structured, suggesting a modest influence of the methyl group on the structure of water. The number of water molecules in the first hydration shell of an alanine molecule is constantly changing; the average number was found to equal 7. The molecular dynamics results show that L-alanine in water does not have a preferred conformation, as all three of the molecule's functional sites (i.e., CH3, NH3+, CO2-) perform rotational movements around the C(alpha)-site bond. PMID:17407339

  8. Perturbation correction for alanine dosimeters in different phantom materials in high-energy photon beams

    NASA Astrophysics Data System (ADS)

    von Voigts-Rhetz, P.; Anton, M.; Vorwerk, H.; Zink, K.

    2016-02-01

    In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in water is well know, the knowledge about the influence of the surrounding phantom material on the response of alanine is sparse. Therefore we investigated the influence of twenty different surrounding/phantom materials for alanine dosimeters in clinical photon fields via Monte Carlo simulations. The relative electron density of the used materials was in the range {{n}e}/{{n}e,\\text{w}}=0.20 up to 1.69, covering almost all materials appearing in inhomogeneous or anthropomorphic phantoms used in radiotherapy. The investigations were performed for three different clinical photon spectra ranging from 6 to 25 MV-X and Co-60 and as a result a perturbation correction {{k}\\text{env}} depending on the environmental material was established. The Monte Carlo simulation show, that there is only a small dependence of {{k}\\text{env}} on the phantom material and the photon energy, which is below  ±0.6%. The results confirm the good suitability of alanine detectors for in-vivo dosimetry.

  9. Perturbation correction for alanine dosimeters in different phantom materials in high-energy photon beams.

    PubMed

    von Voigts-Rhetz, P; Anton, M; Vorwerk, H; Zink, K

    2016-02-01

    In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in water is well know, the knowledge about the influence of the surrounding phantom material on the response of alanine is sparse. Therefore we investigated the influence of twenty different surrounding/phantom materials for alanine dosimeters in clinical photon fields via Monte Carlo simulations. The relative electron density of the used materials was in the range [Formula: see text] up to 1.69, covering almost all materials appearing in inhomogeneous or anthropomorphic phantoms used in radiotherapy. The investigations were performed for three different clinical photon spectra ranging from 6 to 25 MV-X and Co-60 and as a result a perturbation correction [Formula: see text] depending on the environmental material was established. The Monte Carlo simulation show, that there is only a small dependence of [Formula: see text] on the phantom material and the photon energy, which is below  ±0.6%. The results confirm the good suitability of alanine detectors for in-vivo dosimetry. PMID:26758810

  10. Effects of anoxia, pyruvate, and lactate on distribution of N-13 glutamate in myocardium

    SciTech Connect

    Krivokapich, J.; Keen, R.E.; Barrio, J.R.; Douglas, A.; Watanabe, C.R.; Wittmer, S.; Shine, K.I.; Phelps, M.E.

    1984-01-01

    The primary purpose of this study was to determine the effect of anoxia on the fate of N-13 labeled glutamate (glu) in myocardial tissue. Boluses of N-13-glu were injected arterially into isolated, arterially perfused rabbit interventricular septa under control conditions, during anoxia, and during perfusion with 2 mM pyruvate or lactate. In one set of experiments, time-activity curves were generated after the boluses. In another set of experiments, --0.1g of tissue was cut from the septum at 6 minutes after each injection. These samples were analyzed by reverse-phase HPLC. Under control conditions, glu accounted for 58% of the total N-13 radioactivity present in the sample and aspartate (asp), alanine (ala) and glutamine (gln) accounting for 20%, 16%, and 4%, respectively. During anoxia, the dominant change was an increase in ala to 40% of the N-13 radioactivity with an accompanying decrease in glu to 35%. Pyruvate perfusion produced a decrease in glu and increase in ala similar to the changes induced by anoxia. The changes due to lactate were in the same direction but less profound. Analysis of the time-activity curves revealed 2 components. The fraction of N-13 in the residual fraction was not different during anoxia as compared to control conditions. The t 1/2 of this fraction, however, became much shorter. The authors conclude that anoxia induces an increase in ala secondary to increased pyruvate availability. This is reflected in the time-activity curves as a faster washout of N-13 from the septa.

  11. Portable system for continuous ex vivo measurements of lactate.

    PubMed

    Håkanson, H; Kyröläinen, M; Mattiasson, B

    1993-01-01

    The lactate profile in serum was monitored continuously in volunteers under physical exercise on a test bicycle. The assay was operated ex vivo by means of continuous sampling through a coaxial catheter. After dialysis online, lactate was converted by means of lactate oxidase immobilized to porous glass, and the depletion of oxygen was registered by means of a Clark electrode. Good agreement between the continuous monitoring and off-line analyses was found. PMID:8357576

  12. Enhanced responsiveness to selective serotonin reuptake inhibitors during lactation.

    PubMed

    Jury, Nicholas J; McCormick, Betsy A; Horseman, Nelson D; Benoit, Stephen C; Gregerson, Karen A

    2015-01-01

    The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence

  13. Removal of an N-terminal peptide from mitochondrial aspartate aminotransferase abolishes its interactions with mitochondria in vitro.

    PubMed Central

    O'Donovan, K M; Doonan, S; Marra, E; Passarella, S; Quagliariello, E

    1985-01-01

    Treatment of mitochondrial aspartate aminotransferase from rat liver with trypsin leads to specific cleavage of the bonds between residues 26 and 27, and residues 31 and 32. The proteolysed enzyme has only a small residual catalytic activity, but retains a conformation similar to that of the native form as judged by accessibility and reactivity of cysteine residues. Proteolysis abolishes the ability of the enzyme either to bind to mitochondria or to be imported into the organelles. This suggests that the N-terminal segment of the native enzyme is essential for both of these functions, at least in the model system used to study the import process. PMID:4026799

  14. Ultradian rhythmicity of tyrosine aminotransferase activity in Euglena gracillis: Analysis by cosine and non-sinusoidal fitting procedures

    NASA Astrophysics Data System (ADS)

    Neuhaus-Steinmetz, Ulrich; Balzer, Ivonne; Hardeland, Rüdiger

    1990-03-01

    Although the geophysical periodicity of the earth's rotation corresponds to a biological cyclicity of ca. 24 h, cellular temporal organization comprises a multifrequency time structure, in which ultradian rhythms may be regarded as subelements of the circadian oscillator. In Euglena gracilis kept under conditons in which various cellular functions oscillate with a circadian period, tyrosine aminotransferase activity exhibited predominantly an ultradian cycle, whereas its circadian frequency was only weakly expressed. Ultradian period lengths were in the range of 4 5 h, as demonstrated by least squares fitting of cosines and of a non-sinusoidal regression function.

  15. Substrate Specificity of the Aspartate:Alanine Antiporter (AspT) of Tetragenococcus halophilus in Reconstituted Liposomes*

    PubMed Central

    Sasahara, Ayako; Nanatani, Kei; Enomoto, Masaru; Kuwahara, Shigefumi; Abe, Keietsu

    2011-01-01

    The aspartate:alanine antiporter (AspT) of the lactic acid bacterium Tetragenococcus halophilus is a member of the aspartate:alanine exchanger (AAEx) transporter family. T. halophilus AspT catalyzes the electrogenic exchange of l-aspartate1− with l-alanine0. Although physiological functions of AspT were well studied, l-aspartate1−:l-alanine0 antiport mechanisms are still unsolved. Here we report that the binding sites of l-aspartate and l-alanine are independently present in AspT by means of the kinetic studies. We purified His6-tagged T. halophilus AspT and characterized its kinetic properties when reconstituted in liposomes (Km = 0.35 ± 0.03 mm for l-aspartate, Km = 0.098 ± 0 mm for d-aspartate, Km = 26 ± 2 mm for l-alanine, Km = 3.3 ± 0.2 mm for d-alanine). Competitive inhibition by various amino acids of l-aspartate or l-alanine in self-exchange reactions revealed that l-cysteine selectively inhibited l-aspartate self-exchange but only weakly inhibited l-alanine self-exchange. Additionally, l-serine selectively inhibited l-alanine self-exchange but barely inhibited l-aspartate self-exchange. The aspartate analogs l-cysteine sulfinic acid, l-cysteic acid, and d-cysteic acid competitively and strongly inhibited l-aspartate self-exchange compared with l-alanine self-exchange. Taken together, these kinetic data suggest that the putative binding sites of l-aspartate and l-alanine are independently located in the substrate translocation pathway of AspT. PMID:21719707

  16. Substrate specificity of the aspartate:alanine antiporter (AspT) of Tetragenococcus halophilus in reconstituted liposomes.

    PubMed

    Sasahara, Ayako; Nanatani, Kei; Enomoto, Masaru; Kuwahara, Shigefumi; Abe, Keietsu

    2011-08-19

    The aspartate:alanine antiporter (AspT) of the lactic acid bacterium Tetragenococcus halophilus is a member of the aspartate:alanine exchanger (AAEx) transporter family. T. halophilus AspT catalyzes the electrogenic exchange of L-aspartate(1-) with L-alanine(0). Although physiological functions of AspT were well studied, L-aspartate(1-):L-alanine(0) antiport mechanisms are still unsolved. Here we report that the binding sites of L-aspartate and L-alanine are independently present in AspT by means of the kinetic studies. We purified His(6)-tagged T. halophilus AspT and characterized its kinetic properties when reconstituted in liposomes (K(m) = 0.35 ± 0.03 mm for L-aspartate, K(m) = 0.098 ± 0 mm for D-aspartate, K(m) = 26 ± 2 mm for L-alanine, K(m) = 3.3 ± 0.2 mm for D-alanine). Competitive inhibition by various amino acids of L-aspartate or L-alanine in self-exchange reactions revealed that L-cysteine selectively inhibited L-aspartate self-exchange but only weakly inhibited L-alanine self-exchange. Additionally, L-serine selectively inhibited L-alanine self-exchange but barely inhibited L-aspartate self-exchange. The aspartate analogs L-cysteine sulfinic acid, L-cysteic acid, and D-cysteic acid competitively and strongly inhibited L-aspartate self-exchange compared with L-alanine self-exchange. Taken together, these kinetic data suggest that the putative binding sites of L-aspartate and L-alanine are independently located in the substrate translocation pathway of AspT. PMID:21719707

  17. Lactate dehydrogenase in sickle cell disease.

    PubMed

    Stankovic Stojanovic, Katia; Lionnet, François

    2016-07-01

    Lactate dehydrogenase (LDH) activity is elevated in many pathological states. Interest in LDH activity in sickle cell disease (SCD) has developed out of an increased comprehension of the pathophysiological process and the clinical course of the disease. Elevated LDH activity in SCD comes from various mechanisms, especially intravascular hemolysis, as well as ischemia-reperfusion damage and tissular necrosis. Intravascular hemolysis is associated with vasoconstriction, platelet activation, endothelial damage, and vascular complications. LDH has been used as a diagnostic and prognostic factor of acute and chronic complications. In this review we have evaluated the literature where LDH activity was examined during steady-state or acute conditions in SCD. PMID:27138446

  18. Bipolar Depression: Pregnancy, Postpartum, and Lactation.

    PubMed

    Wald, Marla F; Muzyk, Andrew J; Clark, Drue

    2016-03-01

    Medication management of bipolar depression in pregnancy and lactation is best done by assessing each patient's and family's needs in detail. Keeping pregnant patients as psychiatrically stable as possible is the most important principle for clinicians. Unfortunately, there is no risk-free situation for patients with psychiatric illness. This is often the most difficult and hard to accept reality for these patients, families, and clinicians. Clinicians serve these patients best by being as transparent as possible about the risk/benefit analysis of each patient's situation with the realization that ultimately the decisions are made by the patient and family. PMID:26876318

  19. Not only osmoprotectant: betaine increased lactate dehydrogenase activity and L-lactate production in lactobacilli.

    PubMed

    Zou, Huibin; Wu, Zaiqiang; Xian, Mo; Liu, Hui; Cheng, Tao; Cao, Yujin

    2013-11-01

    Lactobacilli are commonly used for industrial production of polymer-grade L-lactic acid. The present study tested the Tween 80 alternative betaine in L-lactate production by several industrial lactobacilli. In flask fermentation of Lactobacillus casei, Lactobacillus buchneri, Lactobacillus lactis and Lactobacillus rhamnosus, the betaine addition (2g/l) had similar osmoprotectant effect with Tween 80 but had increased the lactate dehydrogenase activities and L-lactate production than Tween 80 control. In fed-batch fermentation of L. casei, betaine supplementation improved the L-lactic acid titer to 190 g/l, the yield to 95.5% (g L-lactic acid/g glucose), the productivity to 2.6g/lh, and the optical purity to 97.0%. The results demonstrated that supplementation of Tween 80 alternative - betaine in the fermentation medium is feasible for industrial l-lactic acid fermentation by lactobacilli, which will improve the lactate production but will not increase the process costs and modify any process conditions. PMID:24035452

  20. Dynamic 13C NMR analysis of pyruvate and lactate oxidation in the in vivo canine myocardium: evidence of reduced utilization with increased work.

    PubMed

    Rath, D P; Zhu, H; Tong, X; Jiang, Z; Hamlin, R L; Robitaille, P M

    1997-12-01

    In this work, substrate selection was monitored in the left ventricle of the canine myocardium by following pyruvate and lactate oxidation under in vivo conditions at basal and elevated workloads. These studies were conducted in the open chest model using dynamic 13C NMR techniques in the presence and absence of dichloroacetic acid (DCA), a well-known activator of pyruvate dehydrogenase (PDH). Following the infusion of (3-(13)C) pyruvate or (3-(13)C) lactate into the left anterior descending artery, highly variable 13C enrichments of glutamate, alanine, aspartate, and citrate were noted under low (RPP < 14,500 mmHg/min), intermediate (RPP = 15,000-25,000 mmHg/min), and high (RPP > 25,500 mmHg/min) rate pressure products (RPP). At low workloads, the myocardium typically oxidized the infused (3-(13)C) pyruvate or (3-(13)C) lactate and incorporated the labeled carbon into the glutamate pool as expected. However, in a few notable instances (n = 3), 13C-enriched pyruvate and lactate were unable to label the glutamate pool under in vivo conditions even at the lowest RPPs, indicating a lack of selection for these substrates by the tricarboxylic acid (TCA) cycle. Nonetheless, the levels of glutamate C4 enrichment observed at low workloads could usually be enhanced by infusion of DCA. Importantly, 13C NMR extract analysis revealed that (3-(13)C) pyruvate or (3-(13)C) lactate labeling of the glutamate pool was reduced (< 20%) at high workloads in spite of increased DCA concentrations. PMID:9402190

  1. IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes.

    PubMed

    Siekmann, Lothar; Bonora, Roberto; Burtis, Carl A; Ceriotti, Ferruccio; Clerc-Renaud, Pascale; Férard, Georges; Ferrero, Carlo A; Forest, Jean-Claude; Franck, Paul F H; Gella, F Javier; Hoelzel, Wieland; Jørgensen, Poul Jørgen; Kanno, Takashi; Kessner, Art; Klauke, Rainer; Kristiansen, Nina; Lessinger, Jean-Marc; Linsinger, Thomas P J; Misaki, Hideo; Mueller, Mathias M; Panteghini, Mauro; Pauwels, Jean; Schiele, Françoise; Schimmel, Heinz G; Vialle, Arlette; Weidemann, Gerhard; Schumann, Gerhard

    2002-06-01

    This paper is the first in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and with the certification of reference preparations. Other parts deal with: Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic fication of Four Reference Materials for the Determination of Enzymatic Activity of y-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation. PMID:12211661

  2. Combined TL and 10B-alanine ESR dosimetry for BNCT.

    PubMed

    Bartolotta, A; D'Oca, M C; Lo Giudice, B; Brai, M; Borio, R; Forini, N; Salvadori, P; Manera, S

    2004-01-01

    The dosimetric technique described in this paper is based on electron spin resonance (ESR) detectors using an alanine-boric compound acid enriched with (10)B, and beryllium oxide thermoluminescent (TL) detectors; with this combined dosimetry, it is possible to discriminate the doses due to thermal neutrons and gamma radiation in a mixed field. Irradiations were carried out inside the thermal column of a TRIGA MARK II water-pool-type research nuclear reactor, also used for Boron Neutron Capture therapy (BNCT) applications, with thermal neutron fluence from 10(9) to 10(14) nth cm(-2). The ESR dosemeters using the alanine-boron compound indicated ESR signals about 30-fold stronger than those using only alanine. Moreover, a negligible correction for the gamma contribution, measured with TL detectors, almost insensitive to thermal neutrons, was necessary. Therefore, a simultaneous analysis of our TL and ESR detectors allows discrimination between thermal neutron and gamma doses, as required in BNCT. PMID:15353720

  3. Applicability of EPR/alanine dosimetry for quality assurance in proton eye radiotherapy.

    PubMed

    Michalec, B; Mierzwinska, G; Ptaszkiewicz, M; Sowa, U; Stolarczyk, L; Weber, A

    2014-06-01

    A new quality assurance and quality control method for proton eye radiotherapy based on electron paramagnetic resonance (EPR)/alanine dosimetry has been developed. It is based on Spread-Out Bragg Peak entrance dose measurement with alanine detectors. The entrance dose is well correlated with the dose at the facility isocenter, where, during the therapeutic irradiation, the tumour is placed. The unique alanine detector features namely keeping the dose record in a form of stable radiation-induced free radicals trapped in the material structure, and the non-destructive read-out makes this type of detector a good candidate for additional documentation of the patient's exposure over the therapy course. PMID:24876341

  4. Relationship between season, lactation number and incidence of clinical mastitis in different stages of lactation in a Holstein dairy farm

    PubMed Central

    Moosavi, Maede; Mirzaei, Abdolah; Ghavami, Mohsen; Tamadon, Amin

    2014-01-01

    The aim of the present study was to compare the occurrence and duration of clinical mastitis in different seasons, stages of lactation period and parities in a Holstein dairy farm in Iran. A retrospective epidemiological survey from April 2005 to March 2008 was conducted on 884 clinical mastitis cases of 7437 lactations. Data of each case including calendar-date of mastitis onset, days in milk (DIM) of mastitis onset (early: 0-74 DIM; middle: 75-150 DIM, and late ≥ 150 DIM), duration of mastitis, and parity (1, 2, and ≥ 3) were recorded. Based on date of mastitis onset, cases were classified into stages of lactation. Moreover, beginning of mastitis was seasonally categorized. Duration of clinical mastitis after treatment in early lactation was less than late lactation in the first-parity cows (p = 0.005). In early lactation period, the first-parity cows suffered clinical mastitis in days earlier than two other parity groups (p < 0.001). Moreover, in late lactation period, the first-parity cows had clinical mastitis in days later than cows in the third and more parities (p = 0.002). Occurrence of clinical mastitis in summer increased in late lactation period but in winter increased in early lactation period (p = 0.001). In addition, occurrence time of clinical mastitis in summer were in days later than in spring (p = 0.02) and winter (p = 0.03) in early lactation period. In conclusion, occurrence of mastitis in winter and spring during early lactation and in summer during late lactation period were more prevalent especially in lower parities. PMID:25568687

  5. Profound Hypoglycemia in Starved, Ghrelin-deficient Mice Is Caused by Decreased Gluconeogenesis and Reversed by Lactate or Fatty Acids*

    PubMed Central

    Li, Robert Lin; Sherbet, Daniel P.; Elsbernd, Benjamin L.; Goldstein, Joseph L.; Brown, Michael S.; Zhao, Tong-Jin

    2012-01-01

    When mice are subjected to 7-day calorie restriction (40% of normal food intake), body fat disappears, but blood glucose is maintained as long as the animals produce ghrelin, an octanoylated peptide that stimulates growth hormone secretion. Mice can be rendered ghrelin-deficient by knock-out of the gene encoding either ghrelin O-acyltransferase, which attaches the required octanoate, or ghrelin itself. Calorie-restricted, fat-depleted ghrelin O-acyltransferase or ghrelin knock-out mice fail to show the normal increase in growth hormone and become profoundly hypoglycemic when fasted for 18–23 h. Glucose production in Goat−/− mice was reduced by 60% when compared with similarly treated WT mice. Plasma lactate and pyruvate were also low. Injection of lactate, pyruvate, alanine, or a fatty acid restored blood glucose in Goat−/− mice. Thus, when body fat is reduced by calorie restriction, ghrelin stimulates growth hormone secretion, which allows maintenance of glucose production, even when food intake is eliminated. In humans with anorexia nervosa or kwashiorkor, ghrelin and growth hormone are known to be elevated, just as they are in fat-depleted mice. We suggest that these two hormones prolong survival in starved humans as they do in mice. PMID:22474325

  6. Structural and catalytic properties of L-alanine dehydrogenase from Bacillus cereus.

    PubMed

    Porumb, H; Vancea, D; Mureşan, L; Presecan, E; Lascu, I; Petrescu, I; Porumb, T; Pop, R; Bârzu, O

    1987-04-01

    Alanine dehydrogenase from Bacillus cereus, a non-allosteric enzyme composed of six identical subunits, was purified to homogeneity by chromatography on blue-Sepharose and Sepharose 6B-CL. Like other pyridine-linked dehydrogenases, alanine dehydrogenase is inhibited by Cibacron blue, competitively with respect to NADH and noncompetitively with respect to pyruvate. The enzyme was inactivated by 0.1 M glycine/HCl (pH 2) and reactivated by 0.1 M phosphate (pH 8) supplemented with NAD+ or NADH. The reactivation was characterized by sigmoidal kinetics indicating a complex mechanism involving rate-limiting folding and association steps. Cibacron blue interfered with renaturation, presumably by competition with NADH. Chromatography on Sepharose 6B-CL of the partially renatured alanine dehydrogenase led to the separation of several intermediates, but only the hexamer was characterized by enzymatic activity. By immobilization on Sepharose 4B, alanine dehydrogenase from B. cereus retained 66% of the specific activity of the soluble enzyme. After denaturation of immobilized alanine dehydrogenase with 7 M urea, 37% of the initial protein was still bound to Sepharose, indicating that on the average the hexamer was attached to the matrix via, at most, two subunits. The ability of the denatured, immobilized subunits to pick up subunits from solution shows their capacity to fold back to the native conformation after urea treatment. The formation of "hybrids" between subunits of enzyme from B. cereus and Bacillus subtilis demonstrates the close resemblance of the tertiary and quaternary structures of alanine dehydrogenases from these species. PMID:3104322

  7. Relative response of the alanine dosimeter to medium energy x-rays

    NASA Astrophysics Data System (ADS)

    Anton, M.; Büermann, L.

    2015-08-01

    The response of the alanine dosimeter to kilovoltage x-rays with respect to the dose to water was measured, relative to the response to Co-60 radiation. Two series of x-ray qualities were investigated, one ranging from 30 kV to 100 kV tube voltage (TW series), the other one ranging from 70 kV to 280 kV (TH series). Due to the use of the water calorimeter as a primary standard, the uncertainty of the delivered dose is significantly lower than for other published data. The alanine response was measured as described in a previous publication (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The uncertainty component due to the alanine measurement and analysis is ⩽0.4%, the major part of the combined uncertainty of the relative response originates from the uncertainty of the delivered dose. The relative uncertainties of the relative response vary from ⩽2% for the TW series to ⩽1.1% for the TH series. Different from the behaviour of the alanine dosimeter for megavoltage x-rays or electrons, the relative response drops significantly from unity for Co-60 radiation to less than 64% for the TW quality with a tube voltage of 30 kV. In order to reproduce this behaviour through Monte Carlo simulations, not only the ratio of the absorbed dose to alanine to the absorbed dose to water has to be known, but also the intrinsic efficiency, i.e. the dependence of the number of free radicals generated per unit of absorbed dose on the photon energy. This quantity is not yet accessible for the TW series. For a possible use of the alanine dosimeter for kilovoltage x-rays, for example in electronic brachytherapy, users should rely on the measured data for the relative response which have become available with this publication.

  8. Relative response of the alanine dosimeter to medium energy x-rays.

    PubMed

    Anton, M; Büermann, L

    2015-08-01

    The response of the alanine dosimeter to kilovoltage x-rays with respect to the dose to water was measured, relative to the response to Co-60 radiation.Two series of x-ray qualities were investigated, one ranging from 30 kV to 100 kV tube voltage (TW series), the other one ranging from 70 kV to 280 kV (TH series). Due to the use of the water calorimeter as a primary standard, the uncertainty of the delivered dose is significantly lower than for other published data. The alanine response was measured as described in a previous publication (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The uncertainty component due to the alanine measurement and analysis is ⩽0.4%, the major part of the combined uncertainty of the relative response originates from the uncertainty of the delivered dose. The relative uncertainties of the relative response vary from ⩽2% for the TW series to ⩽1.1% for the TH series.Different from the behaviour of the alanine dosimeter for megavoltage x-rays or electrons, the relative response drops significantly from unity for Co-60 radiation to less than 64% for the TW quality with a tube voltage of 30 kV. In order to reproduce this behaviour through Monte Carlo simulations, not only the ratio of the absorbed dose to alanine to the absorbed dose to water has to be known, but also the intrinsic efficiency, i.e. the dependence of the number of free radicals generated per unit of absorbed dose on the photon energy. This quantity is not yet accessible for the TW series.For a possible use of the alanine dosimeter for kilovoltage x-rays, for example in electronic brachytherapy, users should rely on the measured data for the relative response which have become available with this publication. PMID:26216572

  9. The energy dependence of lithium formate and alanine EPR dosimeters for medium energy x rays

    SciTech Connect

    Waldeland, Einar; Hole, Eli Olaug; Sagstuen, Einar; Malinen, Eirik

    2010-07-15

    Purpose: To perform a systematic investigation of the energy dependence of alanine and lilthium formate EPR dosimeters for medium energy x rays. Methods: Lithium formate and alanine EPR dosimeters were exposed to eight different x-ray beam qualities, with nominal potentials ranging from 50 to 200 kV. Following ionometry based on standards of absorbed dose to water, the dosimeters were given two different doses of approximately 3 and 6 Gy for each radiation quality, with three dosimeters for each dose. A reference series was also irradiated to three different dose levels at a {sup 60}Co unit. The dose to water energy response, that is, the dosimeter reading per absorbed dose to water relative to that for {sup 60}Co {gamma}-rays, was estimated for each beam quality. In addition, the energy response was calculated by Monte Carlo simulations and compared to the experimental energy response. Results: The experimental energy response estimates ranged from 0.89 to 0.94 and from 0.68 to 0.90 for lithium formate and alanine, respectively. The uncertainties in the experimental energy response estimates were typically 3%. The relative effectiveness, that is, the ratio of the experimental energy response to that following Monte Carlo simulations was, on average, 0.96 and 0.94 for lithium formate and alanine, respectively. Conclusions: This work shows that lithium formate dosimeters are less dependent on x-ray energy than alanine. Furthermore, as the relative effectiveness for both lithium formate and alanine were systematically less than unity, the yield of radiation-induced radicals is decreased following x-irradiation compared to irradiation with {sup 60}Co {gamma}-rays.

  10. Temperature-sensitive mutants of Escherichia coli K-12 with low activities of the L-alanine adding enzyme and the D-alanyl-D-alanine adding enzyme.

    PubMed

    Lugtenberg, E J; v Schijndel-van Dam, A

    1972-04-01

    A number of properties of temperature-sensitive mutants in murein synthesis are described. The mutants grow at 30 C but lyse at 42 C. One mutant possesses a temperature-sensitive d-alanyl-d-alanine adding enzyme, has an impaired rate of murein synthesis in vivo at both 30 and 42 C, and contains elevated levels of uridine diphosphate-N-acetyl-muramyl-tripeptide (UDP-MurNAc-l-Ala-d-Glu-m-diaminopimelic acid) at 42 C. The other mutant possesses an l-alanine adding enzyme with a very low in vitro activity at both 30 and 42 C. Its in vivo rate of murein synthesis is almost normal at 30 C but is much less at 42 C. When the murein precursors were isolated after incubation of the cells in the presence of (14)C-l-alanine, they contained only a fraction of the radioactivity that could be obtained from a wild-type strain. A genetic nomenclature for genes concerned with murein synthesis is proposed. PMID:4552998

  11. Somatosensory evoked potentials and blood lactate levels.

    PubMed

    Perciavalle, Valentina; Alagona, Giovanna; De Maria, Giulia; Rapisarda, Giuseppe; Costanzo, Erminio; Perciavalle, Vincenzo; Coco, Marinella

    2015-09-01

    We compared, in 20 subjects, the effects of high blood lactate levels on amplitude and latency of P1, N1, P2 and N2 components of lower limb somatosensory evoked potential (SEP), an useful, noninvasive tool for assessing the transmission of the afferent volley from periphery up to the cortex. SEPs were recorded from CPz located over the somatosensory vertex and referenced to FPz with a clavicle ground. Measurements were carried out before, at the end as well as 10 and 20 min after the conclusion of a maximal exercise carried out on a mechanically braked cycloergometer. After the exercise, P2-N2 amplitudes as well as latency of P1 and N1 components showed small but significant reductions. On the contrary, latency of N2 component exhibited a significant increase after the exercise's conclusion. These results suggest that blood lactate appears to have a protective effect against fatigue, at least at level of primary somatosensory cortex, although at the expense of efficiency of adjacent areas. PMID:25876852

  12. Blood lactate levels of decathletes during competition.

    PubMed Central

    Beaulieu, P; Ottoz, H; Grange, C; Thomas, J; Bensch, C

    1995-01-01

    There are many detailed physiological profiles of athletes who participate in a wide variety of sporting activities but few data have been obtained on decathletes. This study defines some physiological characteristics of these athletes and measures capillary lactate concentrations [La(b)] during a laboratory test of progressive maximal exhaustion and the different events during competition. The treadmill test is similar to the 100 m, 400 m and 1500 m in terms of [La(b)] accumulation but only similar to the 1500 m in terms of velocity. The 400 m is the most demanding event with the greatest blood lactate accumulation (mean(s.d.) 16.38(2.36) mmol l-1). The [La(b)] at the end of the 110 m hurdles is significantly lower than in any other racing events (mean(s.d.) 6.96(1.32) mmol l-1) compared with mean(s.d.) 12.14(2.87) and mean(s.d.) 11.44(2.16) for the 100 m and 1500 m respectively. The [La(b)] after the long jump, the high jump and the pole vault are not significantly different (mean(s.d.) 5.30(2.23), 4.64(1.39) and 5.36(1.34) mmol l-1) respectively). PMID:7551765

  13. Anaerobic Accumulation of γ-Aminobutyric Acid and Alanine in Radish Leaves (Raphanus sativus, L.)

    PubMed Central

    Streeter, John G.; Thompson, John F.

    1972-01-01

    In leaves, the anaerobic accumulation of alanine was accompanied by a loss of aspartate, and these changes preceded γ-aminobutyrate accumulation and glutamate loss. Changes in keto acid content did not appear to be the cause of amino acid changes. Accumulation of γ-aminobutyrate was due to acceleration of glutamate decarboxylation and arrest of γ-aminobutyrate transamination. Changes in enzyme content did not explain the changes in reaction rates in vivo. Most of the aspartate may be converted anaerobically to alanine via oxalacetate and pyruvate. PMID:16658004

  14. Steric effect exerted by the proline residue on the antecedent alanine residue.

    PubMed

    Siemión, I Z; Sobczyk, K; Nawrocka, E

    1982-05-01

    Five model tetrapeptides: Ala-Ala-Ala-Ala, Pro-Ala-Ala-Ala, Ala-Pro-Ala-Ala, Ala-Ala-Pro-Ala and Ala-Ala-Ala-Pro, were synthesized and measured in D2O by 13 C-n.m.r. spectroscopy. The spectra analysis led us to the conclusion that for each model (irrespective of pD) in conformational equilibrium, the predominant conformation is the one in which side methyl of alanine preceding proline residue eclipses alanine carbonyl group. The influence of pD changes in cis-trans isomerism of Ala-Pro amide bond was also investigated. PMID:7118413

  15. Clinical significance of lactate in acute cardiac patients

    PubMed Central

    Lazzeri, Chiara; Valente, Serafina; Chiostri, Marco; Gensini, Gian Franco

    2015-01-01

    Lactate, as a metabolite of easy and quick assessment, has been studied over time in critically ill patients in order to evaluate its prognostic ability. The present review is focused on the prognostic role of lactate levels in acute cardiac patients (that is with acute coronary syndrome, cardiogenic shock, cardiac arrest, non including post cardiac surgery patients). In patients with ST-elevation myocardial infarction treated with mechanical revascularization, hyperlactatemia identified a subset of patients at higher risk for early death and in-hospital complications, being strictly related mainly to hemodynamic derangement. The prognostic impact of hyperlactatemia on mortality has been documented in patients with cardiogenic shock and in those with cardiac arrest even if there is no cut-off value of lactate to be associated with worse outcome or to guide resuscitation or hemodynamic management. Therapeutic hypothermia seems to affect per se lactate values which have been shown to progressively decrease during hypothermia. The mechanism(s) accounting for lactate levels during hypothemia seem to be multiple ranging from the metabolic effects of reduced temperatures to the hemodynamic effects of hypothermia (i.e., reduced need of vasopressor agents). Serial lactate measurements over time, or lactate clearance, have been reported to be clinically more reliable than lactate absolute value also in acute cardiac patients. Despite differences in study design, timing of lactate measurements and type of acute cardiac conditions (i.e., cardiogenic shock, cardiac arrest, refractory cardiac arrest), available evidence strongly suggests that higher lactate levels can be observed on admission in non-survivors and that higher lactate clearance is associated with better outcome. PMID:26322188

  16. Increased metallothionein in mouse liver, kidneys, and duodenum during lactation.

    PubMed

    Solaiman, D; Jonah, M M; Miyazaki, W; Ho, G; Bhattacharyya, M H

    2001-03-01

    Lactation-induced increases in cadmium absorption and retention have been demonstrated in mid-lactating mice, but no systematic measurements of endogenous metal-binding protein concentrations during lactation have been reported. Using Cd/hemoglobin radioassay, this study detected significant increases in metallothionein (MT) concentrations in liver (4-fold), kidneys (2-fold), and duodenum (2-fold), but not jejunum, of mouse dams on days 13 and 20 of lactation. These increases occurred in the absence of cadmium exposure and were specific to the lactation period; dams 5 days after weaning showed MT levels that were similar to those of nonpregnant (NP) mice. Similarly, Northern blot analyses of livers from lactating mice demonstrated that MT mRNA concentrations in maternal liver during mid-lactation were 6-fold higher than those observed 5 days after pups were weaned. Gel filtration of final supernatants from the Cd/hemoglobin assay confirmed that the Cd-binding molecule induced during lactation was indeed metallothionein. In addition, chromatographic analyses of cytosols from tissues taken from dams administered small amounts of Cd (66 ng/mouse) showed that the trace amounts of Cd absorbed through the maternal gastrointestinal tract during mid-lactation were also bound to the MT. These results indicate MT induction in mouse dams occurs as a physiological consequence of lactation, requiring no external stimulus. This induced MT participates in binding low levels of dietary cadmium consumed by the dam. During lactation, elevated maternal MT may affect pathways for essential trace metals as well as sequester toxic metals harmful to the neonate. Multiparous humans may have increased risk of accumulating environmental Cd. PMID:11222885

  17. Complementation cloning and sequence analysis of the Chlamydomonas reinhardtii hemL gene encoding glutamate-1-semialdehyde aminotransferase

    SciTech Connect

    Matters, G.L.; Beale, S.I. )

    1993-05-01

    Glutamate-1-semialdehyde amino-transferase (GSAT) catalyzes formation of the tetrapyrrole precursor, [delta]-aminolevulinic acid. GSAT is encoded by the hemL gene. A Chlamydomonas reinhardtii hemL cDNA was selected from a vegetative stage expression library by complementation of Escherichia coli hemL mutant GE 1377. In vitro GSAT activity was ten-fold higher in an extract of the complemented hemL cells than in an extract of uncomplemented mutant cells. The complementing cDNA is 2010 bp long and includes 591 bp of 3' noncoding DNA and an estimated 27 bp of 5' noncoding DNA. The coding region includes the sequence for a putative 30-amino acid chloroplast transit peptide and a 433-amino acid mature protein. The mature protein deduced from the Chlamydomonas cDNA sequence has a molecular weight of 45,880, compared to the value of 43,000 reported for purified Chlamydomonas GSAT (d. Jahn et al., 1991, J. Biol. Chem. 266:161-167). The deduced peptide is 74% identical to Synechococcus GSAT, 70% identical to barley GSAT and 66% identical to tobacco GSAT. The putative pyridoxal binding region has the sequence TTMGKVIGG, which differs somewhat from those reported for other aminotransferases. The deduced putative chloroplast transit peptide has recognizable similarity to barley GSAT transit peptide. Southern analysis of genomic DNA from Chlamydomonas strain CC124, using the cDNA as a probe, indicates that GSAT is probably encoded by a single gene.

  18. Phylobiochemical Characterization of Class-Ib Aspartate/Prephenate Aminotransferases Reveals Evolution of the Plant Arogenate Phenylalanine Pathway[W

    PubMed Central

    Dornfeld, Camilla; Weisberg, Alexandra J.; K C, Ritesh; Dudareva, Natalia; Jelesko, John G.; Maeda, Hiroshi A.

    2014-01-01

    The aromatic amino acid Phe is required for protein synthesis and serves as the precursor of abundant phenylpropanoid plant natural products. While Phe is synthesized from prephenate exclusively via a phenylpyruvate intermediate in model microbes, the alternative pathway via arogenate is predominant in plant Phe biosynthesis. However, the molecular and biochemical evolution of the plant arogenate pathway is currently unknown. Here, we conducted phylogenetically informed biochemical characterization of prephenate aminotransferases (PPA-ATs) that belong to class-Ib aspartate aminotransferases (AspAT Ibs) and catalyze the first committed step of the arogenate pathway in plants. Plant PPA-ATs and succeeding arogenate dehydratases (ADTs) were found to be most closely related to homologs from Chlorobi/Bacteroidetes bacteria. The Chlorobium tepidum PPA-AT and ADT homologs indeed efficiently converted prephenate and arogenate into arogenate and Phe, respectively. A subset of AspAT Ib enzymes exhibiting PPA-AT activity was further identified from both Plantae and prokaryotes and, together with site-directed mutagenesis, showed that Thr-84 and Lys-169 play key roles in specific recognition of dicarboxylic keto (prephenate) and amino (aspartate) acid substrates. The results suggest that, along with ADT, a gene encoding prephenate-specific PPA-AT was transferred from a Chlorobi/Bacteroidetes ancestor to a eukaryotic ancestor of Plantae, allowing efficient Phe and phenylpropanoid production via arogenate in plants today. PMID:25070637

  19. At least two mutant alleles of ornithine delta-aminotransferase cause gyrate atrophy of the choroid and retina in Finns.

    PubMed

    Mitchell, G A; Brody, L C; Sipila, I; Looney, J E; Wong, C; Engelhardt, J F; Patel, A S; Steel, G; Obie, C; Kaiser-Kupfer, M

    1989-01-01

    Gyrate atrophy of the choroid and retina (GA) is an inherited chorioretinal degeneration caused by deficiency of ornithine delta-aminotransferase (OAT; L-ornithine: 2-oxo-acid aminotransferase; EC 2.6.1.13). GA is one of the "Finnish genetic diseases," a group of several rare monogenic disorders that occur with increased frequency in the Finnish population. Using a combination of RNase A protection, genomic cloning, and polymerase chain reaction amplification of genomic DNA, we found one of two missense mutant OAT alleles to be present in each of 16 Finnish GA pedigrees. The first mutation R180T, in which arginine-180 is replaced by threonine, was present in homozygous form in patients from two pedigrees. The second mutation L402P, in which leucine-402 is replaced by proline, was present in homozygous form in patients from 14 pedigrees. Neither mutation was present in 19 Finnish controls. L402P was not present in 18 non-Finnish GA patients but R180T was found in an American GA patient. We constructed full-length mutant cDNAs by amplifying patient cDNA with the polymerase chain reaction and cloning a restriction fragment containing the mutation into an otherwise normal human OAT cDNA. These mutant cDNAs were then expressed in CHO-K1 cells, which lack endogenous OAT. Both R180T and L402P inactivate OAT. These results show molecular heterogeneity in GA alleles even in the Finnish population. PMID:2492100

  20. METABOLIC ADAPTATION TO FEEDING AND FASTING DURING LACTATION IN HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of these studies was to determine the metabolic adaptation to fasting and feeding during lactation. Normal lactating (L) and nonlactating (NL) women (n = 6 each) were studied using infusions of [U-13C]glucose and [2-13C]glycerol during: 1) a 24-h fast, and 2) ingestion of Sustacal (protocol ...

  1. Regional differences in adipocyte lactate production from glucose

    SciTech Connect

    Newby, F.D.; Sykes, M.N.; DiGirolamo, M. )

    1988-11-01

    Having shown that lactate is an important product of glucose metabolism by rat epididymal adipocytes, the authors investigated possible regional differences in adipocyte lactate production and the role of the animals' nutritional state and stage of development. (U-{sup 14}C)glucose metabolism, lactate production, and response to insulin were measured in fat cells isolated from four adipose regions from young lean and older fatter rats, killed either in the fed state or after fasting for 48 h. In the absence of insulin, mesenteric fat cells from either age group metabolized significantly more glucose per cell and converted more glucose to lactate than cells from other depots, regardless of nutritional state. Adipocytes from fasted lean rats showed a significant increase in the relative glucose conversion to lactate in all depots when compared with cells from fed lean rats. Fasting of older fatter rats, however, had limited effects on the relative adipocyte glucose conversion to lactate since lactate production was already high. Mesenteric fat cells had the lowest relative response to insulin, possibly due to the high basal rate of glucose metabolism. These findings indicate that differences exist among adipose regions in the rates of glucose metabolism, lactate production and response to insulin. The anatomical location of the mesenteric adipose depot, coupled with a high metabolic rate and blood perfusion, suggests that mesenteric adipocytes may provide a unique and more direct contribution of metabolic substrates for hepatic metabolism than adipocytes from other depots.

  2. 21 CFR 862.1445 - Lactate dehydrogenase isoenzymes test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Lactate dehydrogenase isoenzymes test system. 862.1445 Section 862.1445 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1445 Lactate...

  3. 21 CFR 862.1445 - Lactate dehydrogenase isoenzymes test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Lactate dehydrogenase isoenzymes test system. 862.1445 Section 862.1445 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1445 Lactate...

  4. 21 CFR 862.1440 - Lactate dehydrogenase test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Lactate dehydrogenase test system. 862.1440 Section 862.1440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1440 Lactate dehydrogenase...

  5. 21 CFR 862.1445 - Lactate dehydrogenase isoenzymes test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Lactate dehydrogenase isoenzymes test system. 862.1445 Section 862.1445 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1445 Lactate...

  6. Zoledronate prevents lactation induced bone loss and results in additional post-lactation bone mass in mice.

    PubMed

    Wendelboe, Mette Høegh; Thomsen, Jesper Skovhus; Henriksen, Kim; Vegger, Jens Bay; Brüel, Annemarie

    2016-06-01

    In rodents, lactation is associated with a considerable and very rapid bone loss, which almost completely recovers after weaning. The aim of the present study was to investigate whether the bisphosphonate Zoledronate (Zln) can inhibit lactation induced bone loss, and if Zln interferes with recovery of bone mass after lactation has ceased. Seventy-six 10-weeks-old NMRI mice were divided into the following groups: Baseline, Pregnant, Lactation, Lactation+Zln, Recovery, Recovery+Zln, and Virgin Control (age-matched). The lactation period was 12days, then the pups were removed, and thereafter recovery took place for 28days. Zln, 100μg/kg, was given s.c. on the day of delivery, and again 4 and 8days later. Mechanical testing, μCT, and dynamic histomorphometry were performed. At L4, lactation resulted in a substantial loss of bone strength (-55% vs. Pregnant, p<0.01), BV/TV (-40% vs. Pregnant, p<0.01), and trabecular thickness (Tb.Th) (-29% vs. Pregnant, p<0.001). Treatment with Zln completely prevented lactation induced loss of bone strength, BV/TV, and Tb.Th at L4. Full recovery of micro-architectural and mechanical properties was found 28days after weaning in vehicle-treated mice. Interestingly, the recovery group treated with Zln during the lactation period had higher BV/TV (+45%, p<0.01) and Tb.Th (+16%, p<0.05) compared with virgin controls. Similar results were found at the proximal tibia and femur. This indicates that Zln did not interfere with the bone formation taking place after weaning. On this background, we conclude that post-lactation bone formation is not dependent on a preceding lactation induced bone loss. PMID:27021151

  7. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...)(4), (c)(4) (where N = 100). The requirement of 40 CFR 721.91(a)(4) that the amount of the substance...-, salt. 721.520 Section 721.520 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical...

  8. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)(4), (c)(4) (where N = 100). The requirement of 40 CFR 721.91(a)(4) that the amount of the substance...-, salt. 721.520 Section 721.520 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical...

  9. Growth and characterization of pure and semiorganic nonlinear optical Lithium Sulphate admixtured l-alanine crystal

    NASA Astrophysics Data System (ADS)

    Vela, T.; Selvarajan, P.; Freeda, T. H.; Balasubramanian, K.

    2013-04-01

    Lithium sulphate admixtured l-alanine (LSLA) salt was synthesized and the solubility of the commercially available l-alanine and the synthesized LSLA sample was determined in de-ionized water at various temperatures. In accordance with the solubility data, the saturated aqueous solutions of l-alanine and lithium admixtured l-alanine were prepared separately and the single crystals of the samples were grown by the solution method with a slow evaporation technique. Studying single x-ray diffraction shows that pure and LSLA crystal belong to the orthorhombic system with a non-centrosymmetric space group P212121. Using the powder x-ray diffraction study, the crystallinity of the grown crystals is confirmed and the diffraction peaks are indexed. The various functional groups present in the pure and LSLA crystal are elucidated from Fourier transform infrared spectroscopy study. UV-visible transmittance is recorded to study the optical transmittance range for the grown crystals. The powder second harmonic generation test confirms the nonlinear optical property of the grown crystals. From the microhardness test, the hardness of the grown crystals is estimated. The dielectric behaviour, such as the dielectric constant and the loss of the sample, are measured as a function of temperature and frequency. The ac conductivity of the grown crystals is also studied and the activation energy is calculated.

  10. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  11. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  12. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  13. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  14. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  15. Synthesis, characterization, and biocompatible properties of alanine-grafted chitosan copolymers.

    PubMed

    Park, Gyu Han; Kang, Min-Sil; Knowles, Jonathan C; Gong, Myoung-Seon

    2016-04-01

    In order to overcome major problems regarding the lack of affinity to solvents and limited reactivity of the free amines of chitosan, introduction of appropriate spacer arms having terminal amine function is considered of interest.L-Alanine-N-carboxyanhydride was grafted onto chitosan via anionic ring-opening polymerization. The chemical and structural characterizations ofL-alanine-grafted chitosan (Ala-g-Cts) were confirmed through Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy ((1)H NMR). In addition, the viscoelastic properties ofAla-g-Cts were examined by means of a rotational viscometer, and thermal analysis was carried out with a thermogravimetric analyzer and differential scanning calorimetry. Morphological changes in the chitosanL-alanine moiety were determined by x-ray diffraction. To determine the feasibility of using these films as biomedical materials, we investigated the effects of theirL-alanine content on physical and mechanical properties. The biodegradation results of crosslinkedAla-g-Cts films were evaluated in phosphate-buffered solution containing lysozyme at 37℃. Proliferation of MC3T3-E1 cells on crosslinkedAla-g-Cts films was also investigated with use of the CCK-8 assay. PMID:26767393

  16. AlaScan: A Graphical User Interface for Alanine Scanning Free-Energy Calculations.

    PubMed

    Ramadoss, Vijayaraj; Dehez, François; Chipot, Christophe

    2016-06-27

    Computation of the free-energy changes that underlie molecular recognition and association has gained significant importance due to its considerable potential in drug discovery. The massive increase of computational power in recent years substantiates the application of more accurate theoretical methods for the calculation of binding free energies. The impact of such advances is the application of parent approaches, like computational alanine scanning, to investigate in silico the effect of amino-acid replacement in protein-ligand and protein-protein complexes, or probe the thermostability of individual proteins. Because human effort represents a significant cost that precludes the routine use of this form of free-energy calculations, minimizing manual intervention constitutes a stringent prerequisite for any such systematic computation. With this objective in mind, we propose a new plug-in, referred to as AlaScan, developed within the popular visualization program VMD to automate the major steps in alanine-scanning calculations, employing free-energy perturbation as implemented in the widely used molecular dynamics code NAMD. The AlaScan plug-in can be utilized upstream, to prepare input files for selected alanine mutations. It can also be utilized downstream to perform the analysis of different alanine-scanning calculations and to report the free-energy estimates in a user-friendly graphical user interface, allowing favorable mutations to be identified at a glance. The plug-in also assists the end-user in assessing the reliability of the calculation through rapid visual inspection. PMID:27214306

  17. Mechanism of inactivation of alanine racemase by beta, beta, beta-trifluoroalanine

    SciTech Connect

    Faraci, W.S.; Walsh, C.T.

    1989-01-24

    The alanine racemases are a group of PLP-dependent bacterial enzymes that catalyze the racemization of alanine, providing D-alanine for cell wall synthesis. Inactivation of the alanine racemases from the Gram-negative organism Salmonella typhimurium and Gram-positive organism Bacillus stearothermophilus with beta, beta, beta-trifluoroalanine has been studied. The inactivation occurs with the same rate constant as that for formation of a broad 460-490-nm chromophore. Loss of two fluoride ions per mole of inactivated enzyme and retention of (1-/sup 14/C)trifluoroalanine label accompany inhibition, suggesting a monofluoro enzyme adduct. Partial denaturation (1 M guanidine) leads to rapid return of the initial 420-nm chromophore, followed by a slower (t1/2 approximately 30 min-1 h) loss of the fluoride ion and /sup 14/CO/sub 2/ release. At this point, reduction by NaB/sub 3/H/sub 4/ and tryptic digestion yield a single radiolabeled peptide. Purification and sequencing of the peptide reveals that lysine-38 is covalently attached to the PLP cofactor. A mechanism for enzyme inactivation by trifluoroalanine is proposed and contrasted with earlier results on monohaloalanines, in which nucleophilic attack of released aminoacrylate on the PLP aldimine leads to enzyme inactivation. For trifluoroalanine inactivation, nucleophilic attack of lysine-38 on the electrophilic beta-difluoro-alpha, beta-unsaturated imine provides an alternative mode of inhibition for these enzymes.

  18. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...)(4), (c)(4) (where N = 100). The requirement of 40 CFR 721.91(a)(4) that the amount of the substance...-, salt. 721.520 Section 721.520 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical...

  19. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...)(4), (c)(4) (where N = 100). The requirement of 40 CFR 721.91(a)(4) that the amount of the substance...-, salt. 721.520 Section 721.520 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical...

  20. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...)(4), (c)(4) (where N = 100). The requirement of 40 CFR 721.91(a)(4) that the amount of the substance...-, salt. 721.520 Section 721.520 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical...