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  1. ALT (Alanine Aminotransferase) Test

    MedlinePlus

    ... to help recognize heart or muscle injury. ALT values are often compared to the results of other tests such as alkaline phosphatase (ALP) , total protein , and bilirubin to help determine which form of liver disease is present. ALT is often used to monitor the treatment ...

  2. 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.

  3. 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.

  4. Prevalence of elevated alanine-aminotransferase (ALT) among US adolescents and associated factors: NHANES 1999-2004

    PubMed Central

    Fraser, Abigail; Longnecker, Matthew P.; Lawlor, Debbie A

    2007-01-01

    Background & aims Non-alcoholic fatty liver disease (NAFLD) is a common cause of liver disease in children and adolescents. The majority of studies of NAFLD in children have been in select populations of the clinically obese. Study aims were to estimate the prevalence of elevated alanine-aminotransferase (ALT, as a marker of NAFLD) in a general contemporary adolescent population and to identify leading risk factors for ALT elevation (> 30 U/L). Methods We analysed data of adolescent participants (age 12-19, N=5586) in NHANES 1999-2004, a representative sample of the civilian non-institutionalized U.S population. Results The prevalence of elevated ALT (>30 U/L) was 7∙4% among white adolescents, 11∙5%, among Mexican Americans, and 6∙0%, among black adolescents. It was prevalent in 12∙4% of males compared to 3∙5% of females. Multivariable associations with elevated ALT were found for sex (OR male versus female = 7∙7, 95%CI: 3∙9, 15∙1), ethnicity (OR black versus white=0∙6, 95%CI: 0∙3, 1∙3; OR Mexican American versus white=1∙6, 95%CI: 1∙0, 2∙6), waist circumference (OR per 1 SD=1∙4, 95%CI: 1∙0, 2∙0), and fasting insulin (OR per 1 SD=1∙ 6, 95%CI: 1∙ 2, 2∙ 1). Age, C-reactive protein and triglycerides were also positively, and socio-economic position inversely associated with elevated ALT. The magnitude of associations with ALT was similar across ethnic groups. Conclusions ALT is associated with waist circumference and insulin resistance even in a young population. These characteristics could be utilized to identify adolescents who may benefit from screening for NAFLD, offering an opportunity to prevent disease progression at an early age. PMID:18054554

  5. Paralogous ALT1 and ALT2 Retention and Diversification Have Generated Catalytically Active and Inactive Aminotransferases in Saccharomyces cerevisiae

    PubMed Central

    Peñalosa-Ruiz, Georgina; Aranda, Cristina; Ongay-Larios, Laura; Colon, Maritrini; Quezada, Hector; Gonzalez, Alicia

    2012-01-01

    Background Gene duplication and the subsequent divergence of paralogous pairs play a central role in the evolution of novel gene functions. S. cerevisiae possesses two paralogous genes (ALT1/ALT2) which presumably encode alanine aminotransferases. It has been previously shown that Alt1 encodes an alanine aminotransferase, involved in alanine metabolism; however the physiological role of Alt2 is not known. Here we investigate whether ALT2 encodes an active alanine aminotransferase. Principal Findings Our results show that although ALT1 and ALT2 encode 65% identical proteins, only Alt1 displays alanine aminotransferase activity; in contrast ALT2 encodes a catalytically inert protein. ALT1 and ALT2 expression is modulated by Nrg1 and by the intracellular alanine pool. ALT1 is alanine-induced showing a regulatory profile of a gene encoding an enzyme involved in amino acid catabolism, in agreement with the fact that Alt1 is the sole pathway for alanine catabolism present in S. cerevisiae. Conversely, ALT2 expression is alanine-repressed, indicating a role in alanine biosynthesis, although the encoded-protein has no alanine aminotransferase enzymatic activity. In the ancestral-like yeast L. kluyveri, the alanine aminotransferase activity was higher in the presence of alanine than in the presence of ammonium, suggesting that as for ALT1, LkALT1 expression could be alanine-induced. ALT2 retention poses the questions of whether the encoded protein plays a particular function, and if this function was present in the ancestral gene. It could be hypotesized that ALT2 diverged after duplication, through neo-functionalization or that ALT2 function was present in the ancestral gene, with a yet undiscovered function. Conclusions ALT1 and ALT2 divergence has resulted in delegation of alanine aminotransferase activity to Alt1. These genes display opposed regulatory profiles: ALT1 is alanine-induced, while ALT2 is alanine repressed. Both genes are negatively regulated by the Nrg1

  6. LIMITED ELEVATIONS IN ANTITUBERCULOSIS DRUG-INDUCED SERUM ALANINE AMINOTRANSFERASE (ALT) LEVELS IN A COHORT OF NIGERIANS ON TREATMENT FOR PULMONARY TUBERCULOSIS AND HIV INFECTION IN YENAGOA.

    PubMed

    Ikuabe, Peter Ogie; Ebuenyi, Ikenna Desmond; Harry, Tubonye Clement

    2015-01-01

    This study, undertaken in a major tertiary hospital in the Niger Delta region of Nigeria was designed to examine the incidence of elevation in serum alanine aminotransference (ALT) in our patients who were on treatment for HIV/AIDS with some of them on antituberculosis drugs. Between January and December 2014, all admission records which include HIV status, Acid fast bacilli Status, Chest radiograph, CD4 cell count, degree of hepatotoxicity during antituberculosis drugs treatment according to WHO definition using clinical findings and ALT levels at baseline (ALTI) and at 4 weeks into treatment with antituberculosis drugs (ALT2) of all the patients on HAART with some on antituberculosis drugs were retrieved and retrospectively analyzed. Of the total of 707 patients on HAART, 80 were on both HAART and anti-tuberculosis treatment.There was a statistically significant correlation between ALT I levels in the PTB negative and PTB positive cohort at baseline χ2 10.725,d.f4,P = 0.030. After 4 weeks of antituberculosis treatment and HAART ALT2 level in expectedly, generally showed downward trend with no statistically significant correlation between PTB status and ALT2 (χ2 = 0.789, d.f2.P = 0.674) CONCLUSION: Anti-tuberculosis drug induced elevation in alanine amino transference is unexpectedly low in our patients on treatment for pulmonary tuberculosis and HIV infection. This is a key finding that requires further studies.

  7. 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

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

    2010-03-01

    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. 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. 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. 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.

  8. Serum gamma-glutamyltransferase, alanine aminotransferase, and aspartate aminotransferase activity in Iranian healthy blood donor men.

    PubMed

    Khedmat, Hossein; Fallahian, Farahnaz; Abolghasemi, Hassan; Hajibeigi, Bashir; Attarchi, Zohre; Alaeddini, Farshid; Holisaz, Mohammad Taghi; Pourali, Masoumeh; Sharifi, Shahin; Zarei, Nasrin

    2007-02-14

    To determine serum gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity, and to assess their correlation with demographic and clinical findings in healthy blood donors. This cross-sectional study was performed in 934 male blood donors, aged 18 to 68 years, who consecutively attended Tehran blood transfusion service in 2006. All participants were seronegative for HBV or HCV infections, non alcohol users, and all underwent a standard interview and anthropometric tests. Clinical and biochemical parameters including AST, ALT, and GGT activities were determined. Patients taking drugs known to cause hepatic fat deposition were excluded. For AST, ALT, and GGT variables, we used 33.33 and 66.66 percentiles, so that each of them was divided into three tertiles. Mean AST, ALT, and GGT activities were 25.26 +/- 12.58 U/L (normal range 5-35 U/L), 33.13 +/- 22.98 (normal range 5-35 U/L), and 25.11 +/- 18.32 (normal range 6-37 U/L), respectively. By univariate analyses, there were significant associations between increasing AST, ALT, or GGT tertiles and age, body weight, body mass index, and waist and hip circumferences (P<0.05). By multiple linear regression analyses, ALT was found to be positively correlated with dyslipidemia (B=6.988, P=0.038), whereas ALT and AST were negatively correlated with age. AST, ALT, and GGT levels had positive correlation with family history of liver disease (B=15.763, P<0.001), (B=32.345, P<0.001), (B=24.415, P<0.001), respectively. Although we did not determine the cutoffs of the upper normal limits for AST, ALT, and GGT levels, we would suggest screening asymptomatic patients with dyslipidemia and also subjects with a family history of liver disease.

  9. Correlation of serum alanine aminotransferase and aspartate aminotransferase with coronary heart disease

    PubMed Central

    Shen, Jianying; Zhang, Jingying; Wen, Jing; Ming, Qiang; Zhang, Ji; Xu, Yawei

    2015-01-01

    Objective: This study aimed to explore the relationship between different risk factors (especially serum alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and coronary heart disease (CHD). Methods: A total of 610 inpatients were recruited. Initial coronary angiography (CAG) was performed to evaluate the severity of coronary lesions. On the basis of findings from CAG, patients were divided into control group (n=260) and CHD group (n=350). Logistic regression analysis was employed for the evaluation of clinical characteristics and biochemical parameters, aiming to explore the relationship between risk factors (including AST and ALT) and CHD. Results: Results showed type 2 diabetes, hypertension, dyslipidemia, smoking and family history of CHD were clinical risk factors of CHD. Laboratory examinations showed the serum levels of triglycerides, low-density lipoprotein, AST and ALT in CHD group were significantly higher than those in control group (P<0.05). Of these parameters, the AST was 50.98±8.12 U/L in CHD group and 20.14±3.94 U/L in control group (P<0.01); the ALT was 42.31±8.34 U/L in CHD group and 18.25±6.38 U/L in control group (P<0.01). Conclusion: The serum levels of AST and ALT in CHD patients are higher than those in controls. High serum AST and ALT are biochemical markers which can be used to predict the severity of CHD and are also independent risk factors of CHD. PMID:26064360

  10. 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

  11. Inhibition study of alanine aminotransferase enzyme using sequential online capillary electrophoresis analysis.

    PubMed

    Liu, Lina; Chen, Yuanfang; Yang, Li

    2014-12-15

    We report the study of several inhibitors on alanine aminotransferase (ALT) enzyme using sequential online capillary electrophoresis (CE) assay. Using metal ions (Na(+) and Mg(2+)) as example inhibitors, we show that evolution of the ALT inhibition reaction can be achieved by automatically and simultaneously monitoring the substrate consumption and product formation as a function of reaction time. The inhibition mechanism and kinetic constants of ALT inhibition with succinic acid and two traditional Chinese medicines were derived from the sequential online CE assay. Our study could provide valuable information about the inhibition reactions of ALT enzyme.

  12. Intramitochondrial localization of alanine aminotransferase in rat-liver mitochondria: comparison with glutaminase and aspartate aminotransferase.

    PubMed

    Masola, B; Devlin, T M

    1995-12-01

    The removal of the outer mitochondrial membrane and hence of constituents of the intermembrane space in rat-liver mitochondria using digitonin showed that phosphate-dependent glutaminase, alanine and aspartate aminotransferase were localized in the mitoplasts. Further fractionation of mitoplasts following their sonication resulted in 90% of glutaminase, 98% of alanine aminotransferase and 48% of aspartate aminotransferase being recovered in the soluble fraction while the remainder of each enzyme was recovered in the sonicated vesicles fraction. These results indicated that glutaminase and alanine aminotransferase were soluble matrix enzymes, the little of each enzyme recovered in the sonicated vesicles fraction being probably due to entrapment in the vesicles. Aspartate aminotransferase had dual localization, in the inner membrane and matrix with the high specific activity in sonicated vesicles confirming its association with the membrane. Activation experiments suggested that the membrane-bound enzyme was localized on the inner side of the inner mitochondrial membrane.

  13. Abdominal obesity validates the association between elevated alanine aminotransferase and newly diagnosed diabetes mellitus.

    PubMed

    Yueh, Chen-Yu; Yang, Yao-Hsu; Sung, Yi-Ting; Lee, Li-Wen

    2014-01-01

    To examine how elevated alanine aminotransferase (ALT) could be associated with newly diagnosed diabetes mellitus. We conducted a cross-sectional analysis on a mass health examination. The odds ratios (ORs) for diabetes mellitus and newly diagnosed diabetes mellitus were compared between people with and without abdominal obesity, together with and without elevated ALT levels. 5499 people were included in this study. Two hundred fifty two (4.6%) fulfilled the diagnosis of diabetes mellitus with 178 (3.2%) undiagnosed before. Metabolic syndrome was vigorously associated with diabetes mellitus and newly diagnosed diabetes mellitus (12.4% vs. 1.4% and 9.0% vs. 0.9%), but elevated ALT alone was not. However, coexisting with obesity, elevated ALTs were robustly associated with diabetes mellitus and newly diagnosed diabetes mellitus. For the incidence of newly diagnosed diabetes mellitus, in comparison to non-obese people with normal ALT (1.7%, OR = 1), obese people especially with elevated ALT levels had significantly higher ORs (obese with ALT ≤ 40 U/L: 4.7%, OR 1.73, 95% CI 1.08-2.77, P 0.023; ALT 41-80 U/L: 6.8%, OR 2.06, 95% CI 1.20-3.55, P 0.009; ALT 81-120 U/L: 8.8%, OR 3.07, 95% CI 1.38-6.84, P 0.006; ALT > 120 U/L: 18.2%, OR 7.44, 95% CI 3.04-18.18, P < 0.001). Abdominal obesity validates the association between elevated alanine aminotransferase and diabetes mellitus and newly diagnosed diabetes mellitus. People with abdominal obesity, especially with coexisting elevated ALT levels should be screened for undiagnosed diabetes mellitus.

  14. Molecular and phenotypic characterization of transgenic wheat and sorghum events expressing the barley alanine aminotransferase.

    PubMed

    Peña, Pamela A; Quach, Truyen; Sato, Shirley; Ge, Zhengxiang; Nersesian, Natalya; Dweikat, Ismail M; Soundararajan, Madhavan; Clemente, Tom

    2017-08-11

    The expression of a barley alanine aminotransferase gene impacts agronomic outcomes in a C3 crop, wheat. The use of nitrogen-based fertilizers has become one of the major agronomic inputs in crop production systems. Strategies to enhance nitrogen assimilation and flux in planta are being pursued through the introduction of novel genetic alleles. Here an Agrobacterium-mediated approach was employed to introduce the alanine aminotransferase from barley (Hordeum vulgare), HvAlaAT, into wheat (Triticum aestivum) and sorghum (Sorghum bicolor), regulated by either constitutive or root preferred promoter elements. Plants harboring the transgenic HvAlaAT alleles displayed increased alanine aminotransferase (alt) activity. The enhanced alt activity impacted height, tillering and significantly boosted vegetative biomass relative to controls in wheat evaluated under hydroponic conditions, where the phenotypic outcome across these parameters varied relative to time of year study was conducted. Constitutive expression of HvAlaAT translated to elevation in wheat grain yield under field conditions. In sorghum, expression of HvAlaAT enhanced enzymatic activity, but no changes in phenotypic outcomes were observed. Taken together these results suggest that positive agronomic outcomes can be achieved through enhanced alt activity in a C3 crop, wheat. However, the variability observed across experiments under greenhouse conditions implies the phenotypic outcomes imparted by the HvAlaAT allele in wheat may be impacted by environment.

  15. 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

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

    PubMed

    Marjani, Abdoljalal; Mehrpouya, Masoumeh; Pourhashem, Zeinab

    2016-07-01

    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. To assess serum γ-Glutamyltransferase (GGT), Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST) activities in healthy blood donors in different ethnic groups in Gorgan. 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. 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. 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.

  17. 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. PMID:27630834

  18. Purification of three aminotransferases from Hydrogenobacter thermophilus TK-6--novel types of alanine or glycine aminotransferase: enzymes and catalysis.

    PubMed

    Kameya, Masafumi; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo

    2010-04-01

    Aminotransferases catalyse synthetic and degradative reactions of amino acids, and serve as a key linkage between central carbon and nitrogen metabolism in most organisms. In this study, three aminotransferases (AT1, AT2 and AT3) were purified and characterized from Hydrogenobacter thermophilus, a hydrogen-oxidizing chemolithoautotrophic bacterium, which has been reported to possess unique features in its carbon and nitrogen anabolism. AT1, AT2 and AT3 exhibited glutamate:oxaloacetate aminotransferase, glutamate:pyruvate aminotransferase and alanine:glyoxylate aminotransferase activities, respectively. In addition, both AT1 and AT2 catalysed a glutamate:glyoxylate aminotransferase reaction. Interestingly, phylogenetic analysis showed that AT2 belongs to aminotransferase family IV, whereas known glutamate:pyruvate aminotransferases and glutamate:glyoxylate aminotransferases are members of family Igamma. In contrast, AT3 was classified into family I, distant from eukaryotic alanine:glyoxylate aminotransferases which belong to family IV. Although Thermococcus litoralis alanine:glyoxylate aminotransferase is the sole known example of family I alanine:glyoxylate aminotransferases, it is indicated that this alanine:glyoxylate aminotransferase and AT3 are derived from distinct lineages within family I, because neither high sequence similarity nor putative substrate-binding residues are shared by these two enzymes. To our knowledge, this study is the first report of the primary structure of bacterial glutamate:glyoxylate aminotransferase and alanine:glyoxylate aminotransferase, and demonstrates the presence of novel types of aminotransferase phylogenetically distinct from known eukaryotic and archaeal isozymes.

  19. [Association of metabolic syndrome markers with abnormal alanine aminotransferase levels in healthy children].

    PubMed

    Arancibia, Gabriel; García, Hernán; Jaime, Francisca; Bancalari, Rodrigo; Harris, Paul R

    2012-07-01

    There is a high prevalence of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) among pediatric patients. The identification of clinical predictors of these conditions would allow a timely treatment. To evaluate the relationship between serum alanine aminotransferase levels and parameters of metabolic syndrome in asymptomatic school students without hepatic illness. A randomized sample of 175 children aged between 9 and 14 years (54% females) was selected, from a database of 3010 students living in Santiago, Chile. Weight, height, abdominal circumference, systolic and diastolic blood pressure were measured. A fasting blood sample was obtained to measure glucose, total cholesterol, HDL, LDL-cholesterol, triglycerides, alanine aminotransferase (ALT) and insulin levels. Forty percent of participants were obese, 17% had metabolic syndrome and 13.1% had abnormal ALT levels. Compared with children with normal ALT levels, the latter had significantly higher waist obesity, body mass index, systolic and diastolic blood pressure and triglycerides. However on multivariate analysis, only waist obesity was independently associated with abnormal ALT levels (adjusted odds ratio 3.93, 95% confidence intervals 1.44-10.78, p = 0.008). Only waist obesity was independently associated with abnormal ALT levels in this sample of children.

  20. Eating a healthy lunch improves serum alanine aminotransferase activity.

    PubMed

    Iwamoto, Masako; Yagi, Kaori; Yazumi, Kayoko; Komine, Airi; Shirouchi, Bungo; Sato, Masao

    2013-09-14

    Nutritional guidance and diet control play important roles in the treatment of obesity and non-alcoholic fatty liver. However, in Japan, nutritional guidance is difficult to provide in practice. Therefore, we evaluated the effects of providing the 'once-a-day' intervention of a healthy lunch on various metabolic parameters. For a 1-month preparatory period, 10 subjects generally consumed the lunches that were provided by the worksite cafeteria. This was followed by a 1-week washout period, after which, the subjects consumed healthy, low-calorie, well-balanced lunches for a 1-month test period. After the preparatory and test periods, blood samples were obtained from all subjects. The serum levels of indices relevant to metabolic syndrome and fatty liver were measured. Serum alanine aminotransferase activity significantly decreased by 20.3% after the healthy intervention. However, the indices of metabolic syndrome did not significantly change. Analysis of the relationship between serum alanine aminotransferase activity and nutrient content indicated that the improvement of serum alanine aminotransferase status was due to the higher vegetable content and lower animal-source protein of the meals provided. In summary, the 'once-a-day' intervention of providing a healthy lunch improved serum alanine aminotransferase status. A diet high in vegetables and low in animal-based protein is important in maintaining a healthy condition.

  1. Eating a healthy lunch improves serum alanine aminotransferase activity

    PubMed Central

    2013-01-01

    Background Nutritional guidance and diet control play important roles in the treatment of obesity and non-alcoholic fatty liver. However, in Japan, nutritional guidance is difficult to provide in practice. Therefore, we evaluated the effects of providing the ‘once-a-day’ intervention of a healthy lunch on various metabolic parameters. Methods For a 1-month preparatory period, 10 subjects generally consumed the lunches that were provided by the worksite cafeteria. This was followed by a 1-week washout period, after which, the subjects consumed healthy, low-calorie, well-balanced lunches for a 1-month test period. After the preparatory and test periods, blood samples were obtained from all subjects. The serum levels of indices relevant to metabolic syndrome and fatty liver were measured. Results Serum alanine aminotransferase activity significantly decreased by 20.3% after the healthy intervention. However, the indices of metabolic syndrome did not significantly change. Analysis of the relationship between serum alanine aminotransferase activity and nutrient content indicated that the improvement of serum alanine aminotransferase status was due to the higher vegetable content and lower animal-source protein of the meals provided. Conclusions In summary, the ‘once-a-day’ intervention of providing a healthy lunch improved serum alanine aminotransferase status. A diet high in vegetables and low in animal-based protein is important in maintaining a healthy condition. PMID:24034595

  2. Prevalence and predictors of alanine aminotransferase elevation among normal weight, overweight and obese youth in Mexico.

    PubMed

    Purcell, Maura; Flores, Yvonne N; Zhang, Zuo-Feng; Denova-Gutiérrez, Edgar; Salmeron, Jorge

    2013-09-01

    This study aimed to determine the prevalence of and risk factors associated with elevated alanine aminotransferase (ALT) levels among a sample of normal weight, overweight and obese youth from two urban populations in Central Mexico. Baseline data from 1262 youth aged 8-19 years who participated in the Mexican Health Worker Cohort Study from March 2004 to April 2006 were reviewed, including 680 girls and 582 boys, with a total of 83 participants with elevated ALT level (>40 U/L). Information was obtained from self-administered questionnaires, anthropometric results and clinical measurements. Associations of interest were examined using multivariate logistic regression models. A total of 3.8% of girls and 9.8% of boys had elevated ALT levels. Elevated ALT was observed in 28.9% of the obese and 14.2% of the overweight participants. Metabolic syndrome (MS) occurred in 6.1% of the study population and those with MS had a high percentage of elevated ALT (14.5% of girls and 40.0% of boys, respectively). Abdominal obesity and insulin resistance were also associated with a greater risk of elevated ALT. Obesity and certain metabolic risk factors are important predictors for elevated ALT. Screening for ALT levels in obese youth could help to identify those at risk and reduce the possibility of future liver diseases. © 2013 Wiley Publishing Asia Pty Ltd and Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.

  3. Diurnal variation in serum alanine aminotransferase activity in the US population.

    PubMed

    Ruhl, Constance E; Everhart, James E

    2013-02-01

    Serum alanine aminotransferase (ALT) activity has been reported to be greater in the afternoon than the early morning, but data are scarce. We examined diurnal variation of ALT in a national population-based sample. Participants in the 1999 to 2008 US National Health and Nutrition Examination Survey were randomly assigned to morning (AM; n = 4474 adolescents, 11,235 adults) or afternoon/evening (PM; n = 4887 adolescents, 11,735 adults) examinations. We examined ALT distributions graphically and compared both geometric mean ALT and the prevalence of elevated ALT, defined as >31 IU/L for adolescent boys, >24 IU/L for adolescent girls, >43 IU/L for adult men, and >30 IU/L for adult women, between AM and PM examination groups. The examination groups were similar with the exception in the AM group of a longer fasting time and slightly higher prevalence of diabetes among adolescents and viral hepatitis B among adult women. ALT distributions were similar between examination sessions among the 4 groups. Among adolescents and men, neither mean ALT nor prevalence of abnormal ALT differed by examination group. Among women, mean ALT was statistically significant, but minimally higher in the PM group (19.6 IU/L) than the AM group (19.1 IU/L; P = 0.009). Among 1 subgroup, women with chronic viral hepatitis, there was a higher prevalence of abnormal ALT in the PM group (P = 0.018 in unadjusted analysis). Adjusting for liver injury risk factors had little effect on the difference in mean ALT. In general, clinically significant diurnal variation in ALT activity was not found in the US population.

  4. Clinical features of hepatitis C virus carriers with persistently normal alanine aminotransferase levels.

    PubMed

    Uto, Hirofumi; Mawatari, Seiich; Kumagai, Kotaro; Ido, Akio; Tsubouchi, Hirohito

    2012-02-01

    Hepatitis C virus (HCV) infection causes chronic hepatitis, which frequently leads to hepatic fibrosis and hepatocellular carcinoma (HCC). Alanine aminotransferase (ALT) is a biomarker of hepatocyte injury and is associated with the progression of hepatic fibrosis. Advanced hepatic fibrosis also predisposes HCV carriers to a risk of HCC. In contrast, some cases with persistent HCV infection have normal ALT levels that persist for a long time, and these HCV carriers have no or mild hepatitis and hepatic fibrosis. These HCV carriers are defined as persistent normal ALT (PNALT) cases and their risk of HCC is low compared to HCV carriers with abnormal ALT. However, there are various definitions of normal ALT and PNALT, and advanced hepatic fibrosis may be missed without a liver biopsy. In addition, there is also a risk of ALT elevation in HCV carriers with PNALT, which increases the risk of progression to hepatic fibrosis and HCC. Most HCV carriers with PNALT have asymptomatic or nonspecific symptoms. HCV carriers with PNALT are also considered to be responsive to interferon-based treatment. Thus, assessment of hepatic fibrosis is important in HCV carriers, and the eradication of HCV infection is more likely in HCV carriers with evidence of hepatic fibrosis, regardless of their ALT levels.

  5. Elevated alanine aminotransferase levels in HIV-infected persons without hepatitis B or C virus coinfection.

    PubMed

    Alghamdi, Saad; Alrbiaan, Abdullah; Alaraj, Ali; Alhuraiji, Ahmad; Alghamdi, Mohammad; Alrajhi, Abdulrahman

    2016-01-01

    Mortality related to human immunodeficiency (HIV) has improved with the use of antiretroviral therapy; however, liver disease-related mortality remains a major concern for the HIV population. Elevation of alanine aminotransferase (ALT) has been noted in HIV-infected persons even without viral hepatitis infection. The objective of this study was to determine the incidence and prevalence of chronic alanine ALT elevation among patients infected with HIV who are negative for hepatitis B or C infection. Retrospective chart review. We reviewed the medical records of all patients infected with HIV who had been treated from November 2002 to December 2010. Patients with an unknown or positive HBV or HCV infection status were excluded. We identified patient demographics, route of transmission, peak viral load, and nadir CD4 count. We followed 440 patients for up to 2265 person-years. A total of 123 patients developed chronically elevated ALT levels, with an incidence of 5.8 cases per 100 person-years. Chronically elevated ALT levels were associated with high HIV viral load, mean body mass index, and diabetes mellitus. We found exposure to lamivudine in 58% of the patients, efavirenz in 41%, and zidovudine in 38%. Abdominal ultrasounds revealed fatty liver in 20 of 39 (51%) of the patients. Among patients without viral hepatitis coinfection, the prevalence and incidence of chronic elevated ALT levels were high and accompanied by high HIV RNA levels and increased BMI. The limitations of this report are its retrospective nature and lack of a control group.

  6. Alanine aminotransferase and mortality in patients with type 2 diabetes (ZODIAC-38).

    PubMed

    Deetman, Petronella E; Alkhalaf, Alaa; Landman, Gijs W D; Groenier, Klaas H; Kootstra-Ros, Jenny E; Navis, Gerjan; Bilo, Henk J G; Kleefstra, Nanne; Bakker, Stephan J L

    2015-08-01

    Combined data suggest a bimodal association of alanine aminotransferase (ALT) with mortality in the general population. Little is known about the association of ALT with mortality in patients with type 2 diabetes. We therefore investigated the association of ALT with all-cause, cardiovascular and noncardiovascular mortality in patients with type 2 diabetes. A prospective study was performed in patients with type 2 diabetes, treated in primary care, participating in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study. Cox regression analyses were performed to determine the associations of log2 -transformed baseline ALT with all-cause, cardiovascular and noncardiovascular mortality. In 1187 patients with type 2 diabetes (67 ± 12 years, 45% female), ALT levels were 11 (8-16) U/L. During median follow-up for 11.1 (6.1-14.0) years, 553 (47%) patients died, with 238 (20%) attributable to cardiovascular causes. Overall, ALT was inversely associated with all-cause mortality (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.72-0.92), independently of potential confounders. This was less attributable to cardiovascular mortality (HR 0.87; 95% CI 0.72-1.05), than to noncardiovascular mortality (HR 0.77; 95% CI 0.65-0.90). Despite the overall inverse association of ALT with mortality, it appeared that a bimodal association with all-cause mortality was present with increasing risk for levels of ALT above normal (P = 0.003). In patients with type 2 diabetes, low levels of ALT are associated with an increased risk of all-cause mortality, in particular noncardiovascular mortality, compared to normal levels of ALT, while risk again starts to increase when levels are above normal. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

  7. The Association of Low Serum Alanine Aminotransferase Activity With Mortality in the US Population

    PubMed Central

    Ruhl, Constance E.; Everhart, James E.

    2013-01-01

    Elevated alanine aminotransferase (ALT) activity, an important marker of liver injury, has been associated inconsistently with higher mortality. We evaluated whether persons with nonelevated ALT levels are the most appropriate comparison group by examining the relationships of low ALT with mortality and body composition in the US National Health and Nutrition Examination Survey (NHANES). In NHANES 1988–1994, the mortality risk of persons in ALT deciles 1, 2, 3, and 10 was compared with that of persons in deciles 4–9 (mortality was relatively flat across these deciles) over an 18-year period (through 2006) among 14,950 viral-hepatitis-negative adults. In NHANES 1999–2006, low ALT was evaluated in association with dual-energy x-ray absorptiometry body composition measures among 15,028 adults. Multivariate-adjusted mortality was higher for decile 1 (hazard ratio (HR) = 1.42, 95% confidence interval (CI): 1.24, 1.63), decile 2 (HR = 1.27, 95% CI: 1.06, 1.53), and decile 3 (HR = 1.25, 95% CI: 1.04, 1.50) and nonsignificantly higher for decile 10 (HR = 1.21, 95% CI: 0.91, 1.61) than for deciles 4–9. Adjusted appendicular lean mass was decreased among the lowest ALT deciles. In the US population, low ALT was associated with higher mortality risk, possibly attributable to decreased appendicular lean mass. For mortality studies of elevated ALT levels, the most appropriate comparison group is persons in the middle range of ALT rather than all persons with nonelevated ALT. PMID:24071009

  8. Gender differences in healthy ranges for serum alanine aminotransferase levels in adolescence.

    PubMed

    Poustchi, Hossein; George, Jacob; Esmaili, Saeed; Esna-Ashari, Farzaneh; Ardalan, Gelayol; Sepanlou, Sadaf Ghajarieh; Alavian, Seyed Moayed

    2011-01-01

    There is a worldwide epidemic of obesity among adolescents who subsequently are at increased risk for the development of non alcoholic fatty liver disease (NAFLD). The serum alanine aminotransferase (ALT) is the most frequently used test for screening these individuals, but no age and gender-specific upper limits of normal (ULN) based on healthy population data in children are available. The objective of the present study was to define ULN for ALT in healthy children in order to use this as a tool for case finding. A total of 975 school children (aged 7-18 years) were included in the study cohort. Highly significant correlations (all p<0.001) were noted between ALT values and measures of BMI, systolic and diastolic blood pressure, insulin levels, HOMA-IR, total cholesterol and triglyceride concentrations. In order to define the population with no risk factors, we excluded subjects having abnormal values for factors that correlated with ALT. This population comprised 186 boys and 185 girls. In boys, median serum ALT levels were 16 IU/L and 9, 11, 18, and 30 IU/L for the 5th, 25th, 75th, and 95th percentiles. In girls, median serum ALT was 13, and 7, 9, 16, and 21 IU/L for the 5th, 25th, 75th, and 95th percentiles, respectively. The ULNs for ALT were 30 IU/L and 21 IU/L for boys and girls respectively. We found a linear relationship between age and ALT in females (p<0.001) but not in males. By multiple logistic regression, independent predictors of an elevated ALT included the BMI, waist hip ratio and levels of serum total cholesterol. In females, age was an additional inverse predictor. In children and adolescents, these normal limits for ALT should be applied. Those with persistent elevations should be investigated further.

  9. Association between Serum Uric Acid and Elevated Alanine Aminotransferase in the General Population

    PubMed Central

    Chen, Shuang; Guo, Xiaofan; Yu, Shasha; Sun, Guozhe; Yang, Hongmei; Li, Zhao; Sun, Yingxian

    2016-01-01

    Background: Both the serum uric acid (SUA) level and elevated alanine aminotransferase (ALT) are related to metabolic syndrome. However, the association between SUA and elevated ALT has not been elucidated in the general population. The objective of this study was to investigate the association between SUA and elevated ALT in the general population of China; Methods: A total of 11,572 adults (≥35 years of age) participated in this survey. Elevated ALT was defined as >40 U/L. SUA ≥ 7.0 mg/dL in males or ≥6.0 mg/dL in females was defined as hyperuricemia. SUA within the reference range was divided into quartiles, and its associations with elevated ALT were evaluated by logistic regressions; Results: A total of 7.4% participants had elevated ALT. The prevalence of hyperuricemia was 14.9% in males and 7.3% in females. There was a significantly positive dose-response association between SUA levels and the prevalence of elevated ALT. After adjusting for potential confounders, a positive relationship for elevated ALT was observed in subjects with hyperuricemia (odds ratio [OR]: 2.032, 95% confidence interval [CI]: 1.443–2.861 for men; OR: 2.045, 95% CI: 1.221–3.425 for women, both p < 0.05). Within the reference range, the association between SUA and elevated ALT persisted in the fourth quartile (OR: 1.467, 95% CI: 1.063–2.025 for men; OR: 1.721, 95% CI: 1.146–2.585 for women, both p < 0.05); Conclusions: Our results indicated that an increased SUA level, even within the reference range, was independently associated with elevated ALT in Chinese adults. PMID:27563918

  10. Serum alanine aminotransferase is correlated with hematocrit in healthy human subjects.

    PubMed

    Hu, Yun; Snitker, Soren; Ryan, Kathleen A; Yang, Rongze; Mitchell, Braxton D; Shuldiner, Alan R; Zhu, Dalong; Gong, Da-Wei

    2012-05-01

    Serum alanine aminotransferase (ALT) activity is a widely-used surrogate marker for liver injury. However, mild elevation of serum ALT is frequently observed in apparently healthy individuals, making it sometimes challenging to interpret whether this laboratory abnormality is medically benign or serious. To obtain a better understanding of the factors influencing ALT levels, we examined the relation between ALT and a number of anthropometric and biochemistry measurements in humans. We assessed the associations of ALT with hematocrit (HCT) in 1,200 apparently healthy adults from an Amish population. Multivariate analyses were carried out to determine whether observed associations were independent of other factors known to modulate ALT and HCT, including body mass index (BMI) and sex. The correlation detected in the Amish was then replicated in an independent population sample (N = 9,842) from the National Health and Nutrition Examination Survey (NHANES) III. ALT levels were positively correlated with HCT (r = 0.33, p < 0.0001) in both Amish and NHANES III. The magnitude of association was unchanged after adjustment for BMI, but was reduced by age/sex adjustment to r = 0.18 (p < 0.0001) and r = 0.17 (p < 0.0001) in the Amish and NHANES populations, respectively. HCT accounts for about 3% of the population variation in ALT, which is smaller than the contributions of gender and BMI, but larger than individual blood pressure and cholesterol components. We observed a correlation between ALT and HCT, suggesting that HCT may be a newly identified modulator of ALT in humans.

  11. Serum alanine aminotransferase levels decrease further with carbohydrate than fat restriction in insulin-resistant adults.

    PubMed

    Ryan, Marno Celeste; Abbasi, Fahim; Lamendola, Cindy; Carter, Susan; McLaughlin, Tracey Lynn

    2007-05-01

    Although weight loss interventions have been shown to reduce steatosis in nonalcoholic fatty liver disease (NAFLD), the impact of dietary macronutrient composition is unknown. We assessed the effect on serum alanine aminotransferase (ALT) concentrations of two hypocaloric diets varying in amounts of carbohydrate and fat in obese insulin-resistant individuals, a population at high risk for NAFLD. Post hoc analysis of ALT concentrations was performed in 52 obese subjects with normal baseline values and insulin resistance, as quantified by the steady-state plasma glucose (SSPG) test, who were randomized to hypocaloric diets containing either 60% carbohydrate/25% fat or 40% carbohydrate/45% fat (15% protein) for 16 weeks. The primary end point was change in ALT, which was evaluated according to diet, weight loss, SSPG, and daylong insulin concentrations. Although both diets resulted in significant decreases in weight and SSPG, daylong insulin, and serum ALT concentrations, the 40% carbohydrate diet resulted in greater decreases in SSPG (P < 0.04), circulating insulin (P < 0.01), and ALT (9.5 +/- 9.4 vs. 4.2 +/- 8.3 units/l; P < 0.04) concentrations. ALT changes correlated with improvement in insulin sensitivity (P = 0.04) and daylong insulin (P < 0.01). Individuals with ALT concentrations above the proposed upper limits experienced significant declines in ALT, unlike those with lower ALT levels. In a population at high risk for NAFLD, a hypocaloric diet moderately lower in carbohydrate decreased serum ALT concentrations to a greater degree than a higher-carbohydrate/low-fat diet, despite equal weight loss. This may result from a relatively greater decline in daylong insulin concentrations. Further research with histological end points is needed to further explore this finding.

  12. Histological and Clinical Characteristics of Patients with Chronic Hepatitis C and Persistently Normal Alanine Aminotransferase Levels

    PubMed Central

    Guzman, Grace

    2014-01-01

    Patients with chronic hepatitis C virus (HCV) infection and persistently normal alanine aminotransferase (PNALT) are generally described to have mild liver disease. The aim of this study was to compare clinical and histological features in HCV-infected patients with PNALT and elevated ALT. Patients presenting to the University of Illinois Medical Center, Chicago, who had biopsy proven HCV, an ALT measurement at the time of liver biopsy, at least one additional ALT measurement over the next 12 months, and liver biopsy slides available for review were identified. PNALT was defined as ALT ≤ 30 on at least 2 different occasions over 12 months. Of 1200 patients with HCV, 243 met the study criteria. 13% (32/243) of patients had PNALT while 87% (211/243) had elevated ALT. Significantly more patients with PNALT had advanced fibrosis (F3 and F4) compared to those with elevated ALT (P = 0.007). There was no significant difference in the histology activity index score as well as mean inflammatory score between the two groups. In conclusion, in a well-characterized cohort of patients at a tertiary medical center, PNALT did not distinguish patients with mild liver disease. PMID:24891947

  13. Crystal structures of Aedes aegypti alanine glyoxylate aminotransferase.

    PubMed

    Han, Qian; Robinson, Howard; Gao, Yi Gui; Vogelaar, Nancy; Wilson, Scott R; Rizzi, Menico; Li, Jianyong

    2006-12-01

    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 1.75A 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 2.1A 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.

  14. 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.

  15. Serum alanine aminotransferase elevation during 10 days of acetaminophen administration in non-drinkers

    PubMed Central

    Heard, Kennon J.; Green, Jody L.; Dart, Richard C.

    2011-01-01

    Asymptomatic alanine aminotransferase (ALT) elevations have been detected with acetaminophen use at the maximum daily dose of 4 grams/day (g/d) for more than 3 consecutive days in subjects with and without concurrent ethanol use. The purpose of this study is to describe the changes in serum ALT activity in non-drinkers treated with acetaminophen for 10 days. Methods Study Objective to describe the change in serum ALT in non-drinkers administered acetaminophen for 10 days. Study Design: Prospective, single arm trial. Setting: Outpatients. Interventions: Acetaminophen 4 g/day starting on day study day 1. Measurements: Serum ALT, total billirubin and international normalized ratio (INR) were measured on study day 0, 4, 7, 9, 11 and 14. Main Results Twenty four subjects completed the trial. Median ALT increased from 24 IU/L at day 0 to 39 IU/L by day 7, remained elevated through day 11 (38 IU/L) and began to trend down by day 14 (35 IU/L). The increase in ALT during the study was statistically significant (p= 0.0002). Sixty-six percent of subjects had an ALT above the upper limits of normal at day 11; the largest elevation was 3.8 the upper limits of normal. No subject developed symptoms of liver injury or had an elevation in INR or serum bilirubin. Conclusions Daily use of acetaminophen at the daily maximum dose of 4 g/day for 10 days causes asymptomatic ALT elevations in subjects who do not consume ethanol. PMID:20653358

  16. Endocannabinoid receptor blockade reduces alanine aminotransferase in polycystic ovary syndrome independent of weight loss.

    PubMed

    Dawson, Alison J; Kilpatrick, Eric S; Coady, Anne-Marie; Elshewehy, Abeer M M; Dakroury, Youssra; Ahmed, Lina; Atkin, Stephen L; Sathyapalan, Thozhukat

    2017-07-14

    Evidence suggests that endocannabinoid system activation through the cannabinoid receptor 1 (CB1) is associated with enhanced liver injury, and CB1 antagonism may be beneficial. The aim of this study was to determine the impact of rimonabant (CB1 antagonist) on alanine aminotransferase (ALT), a hepatocellular injury marker, and a hepatic inflammatory cytokine profile. Post hoc review of 2 studies involving 50 obese women with PCOS and well matched for weight, randomised to weight reducing therapy; rimonabant (20 mg od) or orlistat (120 mg tds), or to insulin sensitising therapy metformin, (500 mg tds), or pioglitazone (45 mg od). No subject had non-alcoholic fatty liver disease (NAFLD). Treatment with rimonabant for 12 weeks reduced both ALT and weight (p < 0.01), and there was a negative correlation between Δ ALT and Δ HOMA-IR (p < 0.001), but not between Δ ALT and Δ weight. There was a significant reduction of weight with orlistat (p < 0.01); however, orlistat, metformin and pioglitazone had no effect on ALT. The free androgen index fell in all groups (p < 0.05). The inflammatory marker hs-CRP was reduced by pioglitazone (p < 0.001) alone and did not correlate with changes in ALT. The inflammatory cytokine profile for IL-1β, IL-6, IL-7, IL-10, IL12, TNF-α, MCP-1 and INF-γ did not differ between groups. None of the interventions had an effect on biological variability of ALT. Rimonabant through CB1 receptor blockade decreased serum ALT that was independent of weight loss and hepatic inflammatory markers in obese women with PCOS without NAFLD. ISRCTN58369615 (February 2007; retrospectively registered) ISRCTN75758249 (October 2007; retrospectively registered).

  17. Trunk Fat is Associated with Increased Serum Levels of Alanine Aminotransferase in the US

    PubMed Central

    Ruhl, Constance E.; Everhart, James E.

    2010-01-01

    Background & Aims Liver injury is associated with obesity and related measures such as body mass index (BMI) and waist circumference. The relationship between liver injury and body composition has not been evaluated in a population-based study. Methods Using data from a US population-based survey, we examined the contributions of body composition, measured by dual-energy x-ray absorptiometry (DXA), to increased serum alanine aminotransferase (ALT) activity among 11,821 adults without viral hepatitis. Trunk fat, extremity fat, trunk lean, and extremity lean mass were divided by height squared and used to categorize subjects into quintiles; logistic regression odds ratios (OR) were calculated for increased ALT. Results Increased ALT was associated with higher measures of fat and lean mass (p<0.001) after adjustment for alcohol consumption and other liver injury risk factors in separate models for each DXA measure. Trunk fat was associated with increased ALT (p≤0.001) in models also including any 1 of the other 3 measures. Extremity fat was independently inversely associated among women (p<0.001). Trunk and extremity lean mass were not independently related to increased ALT. In models that contained all 4 DXA measures, the OR (95% confidence interval) for increased ALT for the highest, relative to lowest, quintile of trunk fat/height squared was 13.8 (5.4-35.3) for men and 7.8 (3.9-15.8) for women. When BMI, waist circumference, and trunk fat were considered together, only trunk fat remained independently associated with increased ALT. Conclusions Trunk fat is a major body composition determinant of increased ALT, supporting the hypothesis that liver injury can be induced by metabolically active intra-abdominal fat. PMID:20060831

  18. 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

  19. 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.

  20. 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

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

    PubMed

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

    2016-01-01

    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). 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. 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. On the basis of our study results, IBS may be an important condition in certain patients with elevated ALT levels and MS.

  2. Alanine aminotransferase normalization at week 8 predicts viral response during hepatitis C treatment.

    PubMed

    Dogan, Umit Bilge; Akin, Mustafa Salih; Yalaki, Serkan

    2013-12-14

    To investigate alanine aminotransferase (ALT) and sustained virological response (SVR) in chronic hepatitis C (CHC) during peginterferon-ribavirin treatment. One hundred and fifty-one genotype 1 CHC patients underwent treatment for 48 wk with peginterferon and ribavirin, and were retrospectively divided into two groups as having a rapid virological response (RVR) (Group 1, n = 52) and not having an RVR (Group 2, n = 99). We also subdivided each group into two according to the initial ALT level being high (Group 1h and Group 2h) or normal (Group 1n and Group 2n). HCV RNA and ALT levels were measured at baseline; at 4, 12, 24 and 48 wk during the treatment period; and at 24 wk follow-up. ALT levels were also obtained at 8 wk. According to the results of ALT, patients were enrolled in either the follow-up abnormal or follow-up normalized ALT groups at each interval. Patients with high and normal ALT levels were compared for each interval in terms of SVR. The SVR rates were 83% vs 40% (P = 0.000), 82% vs 84% (P = 0.830), and 37% vs 44% (P = 0.466) when comparing Group 1 with 2, 1h with 1n, and 2h with 2n, respectively. In Group 2h, the SVR rates were 34% vs 40% (P = 0.701), 11% vs 52% (P = 0.004), 12% vs 50% (P = 0.007), 7% vs 50% (P = 0.003), 6% vs 53% (P = 0.001), and 0% vs 64% (P = 0.000) when comparing patients with high and normalized ALT levels at week 4, 8, 12, 24, 48 and 72, respectively. The multiple logistic regression analysis revealed that RVR (OR = 7.05; 95%CI: 3.1-16.05, P = 0.000), complete early virological response (cEVR) (OR = 17.55; 95%CI: 6.32-48.76, P = 0.000), normalization of ALT at 8 wk (OR = 3.04; 95%CI: 1.31-7.06, P = 0.008), and at 12 wk (OR = 4.21; 95%CI: 1.65-10.76, P = 0.002) were identified as independent significant predictive factors for SVR. Normalization of ALT at 8 wk may predict viral response during peginterferon-ribavirin treatment in genotype-1 CHC patients especially without RVR.

  3. Yield of diagnostic tests in obese children with an elevated alanine aminotransferase.

    PubMed

    Rudolph, Bryan; Rivas, Yolanda; Kulak, Shulamit; Pan, Debra; Ewart, Michelle; Levin, Terry L; Thompson, John F; Scharbach, Kathryn

    2015-12-01

    Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and affects roughly 10% of children. However, NAFLD is often diagnosed by exclusion - that is, obese children with an elevated alanine aminotransferase (ALT) are screened for other liver diseases in the absence of a biopsy. This testing is nonstandardized, and professional society recommendations differ. This study examines the yield of testing for disorders other than NAFLD in this patient population. A retrospective study was performed in 120 obese, asymptomatic, noncholestatic children with an ALT ≥40 U/L and additional diagnostic testing. No patients were found to have Wilson's, hepatitis A, hepatitis B, hepatitis C, cytomegalovirus, alpha-1 antitrypsin deficiency, autoimmune hepatitis, celiac disease or Epstein-Barr virus. Only one patient (1/120) was identified with definite disease other than NAFLD, which was muscular dystrophy. The positive predictive value of a screening test was 5%, and the specificity was 97%. Of 70 children with an abdominal ultrasound, no significant abnormalities were identified. Extensive testing in asymptomatic, noncholestatic, obese children with an elevated ALT may be of limited diagnostic value and false-positive tests are likely. Large, prospective studies are needed to help focus the work up in this patient population. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  4. Alanine Aminotransferase Variants Conferring Diverse NUE Phenotypes in Arabidopsis thaliana

    PubMed Central

    McAllister, Chandra H.; Good, Allen G.

    2015-01-01

    Alanine aminotransferase (AlaAT, E.C. 2.6.1.2), is a pyridoxal-5’-phosphate-dependent (PLP) enzyme that catalyzes the reversible transfer of an amino group from alanine to 2-oxoglutarate to produce glutamate and pyruvate, or vice versa. It has been well documented in both greenhouse and field studies that tissue-specific over-expression of AlaAT from barley (Hordeum vulgare, HvAlaAT) results in a significant increase in plant NUE in both canola and rice. While the physical phenotypes associated with over-expression of HvAlaAT have been well characterized, the role this enzyme plays in vivo to create a more N efficient plant remains unknown. Furthermore, the importance of HvAlaAT, in contrast to other AlaAT enzyme homologues in creating this phenotype has not yet been explored. To address the role of AlaAT in NUE, AlaAT variants from diverse sources and different subcellular locations, were expressed in the wild-type Arabidopsis thaliana Col-0 background and alaat1;2 (alaat1-1;alaat2-1) knockout background in various N environments. The analysis and comparison of both the physical and physiological properties of AlaAT over-expressing transgenic plants demonstrated significant differences between plants expressing the different AlaAT enzymes under different external conditions. This analysis indicates that the over-expression of AlaAT variants other than HvAlaAT in crop plants could further increase the NUE phenotype(s) previously observed. PMID:25830496

  5. Alanine aminotransferase variants conferring diverse NUE phenotypes in Arabidopsis thaliana.

    PubMed

    McAllister, Chandra H; Good, Allen G

    2015-01-01

    Alanine aminotransferase (AlaAT, E.C. 2.6.1.2), is a pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes the reversible transfer of an amino group from alanine to 2-oxoglutarate to produce glutamate and pyruvate, or vice versa. It has been well documented in both greenhouse and field studies that tissue-specific over-expression of AlaAT from barley (Hordeum vulgare, HvAlaAT) results in a significant increase in plant NUE in both canola and rice. While the physical phenotypes associated with over-expression of HvAlaAT have been well characterized, the role this enzyme plays in vivo to create a more N efficient plant remains unknown. Furthermore, the importance of HvAlaAT, in contrast to other AlaAT enzyme homologues in creating this phenotype has not yet been explored. To address the role of AlaAT in NUE, AlaAT variants from diverse sources and different subcellular locations, were expressed in the wild-type Arabidopsis thaliana Col-0 background and alaat1;2 (alaat1-1;alaat2-1) knockout background in various N environments. The analysis and comparison of both the physical and physiological properties of AlaAT over-expressing transgenic plants demonstrated significant differences between plants expressing the different AlaAT enzymes under different external conditions. This analysis indicates that the over-expression of AlaAT variants other than HvAlaAT in crop plants could further increase the NUE phenotype(s) previously observed.

  6. Elevated aspartate and alanine aminotransferase levels and natural death among patients with methamphetamine dependence.

    PubMed

    Kuo, Chian-Jue; Tsai, Shang-Ying; Liao, Ya-Tang; Conwell, Yeates; Lee, Wen-Chung; Huang, Ming-Chyi; Lin, Shih-Ku; Chen, Chiao-Chicy; Chen, Wei J

    2012-01-01

    Methamphetamine is one of the fastest growing illicit drugs worldwide, causing multiple organ damage and excessive natural deaths. The authors aimed to identify potential laboratory indices and clinical characteristics associated with natural death through a two-phase study. Methamphetamine-dependent patients (n = 1,254) admitted to a psychiatric center in Taiwan between 1990 and 2007 were linked with a national mortality database for causes of death. Forty-eight subjects died of natural causes, and were defined as the case subjects. A time-efficient sex- and age-matched nested case-control study derived from the cohort was conducted first to explore the potential factors associated with natural death through a time-consuming standardized review of medical records. Then the identified potential factors were evaluated in the whole cohort to validate the findings. In phase I, several potential factors associated with natural death were identified, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), comorbid alcohol use disorder, and the prescription of antipsychotic drugs. In phase II, these factors were confirmed in the whole cohort using survival analysis. For the characteristics at the latest hospital admission, Cox proportional hazards models showed that the adjusted hazard ratios for natural death were 6.75 (p<0.001) in the group with markedly elevated AST (>80 U/L) and 2.66 (p<0.05) in the group with mildly elevated AST (40-80 U/L), with reference to the control group (<40 U/L). As for ALT, the adjusted hazard ratios were 5.41 (p<0.001), and 1.44 (p>0.05). Comorbid alcohol use disorder was associated with an increased risk of natural death, whereas administration of antipsychotic drugs was not associated with lowered risk. This study highlights the necessity of intensive follow-up for those with elevated AST and ALT levels and comorbid alcohol use disorder for preventing excessive natural deaths.

  7. Observations of alanine aminotransferase and aspartate aminotransferase in THRIVE studies treated orally with ximelagatran.

    PubMed

    Harenberg, Job; Jörg, Ingrid; Weiss, Christel

    2006-01-01

    Treatment of acute venous thromboembolism (VTE) and prophylaxis of recurrent events has been investigated in the THRIVE (THRombin Inhibitor in Venous Thrombe Embolism) Treatment and the THRIVE III trial using the oral direct thrombin inhibitor ximelagatran. Alanine aminotransferase (ALAT) increased in 9.6% and 6.4% of patients in the THRIVE Treatment and THRIVE III trials, respectively. The authors analysed the time course of the ALAT and in additionally of aspartate aminotransferase (ASAT) in blood from 52 and 23 patients participating in the THRIVE Treatment and the THRIVE III trials in Germany. Analysis of variance for repeated measures and t test were performed. In the THRIVE Treatment trial, ALAT was significantly higher at week 2 for enoxaparin/warfarin (p => .0039, t test) and at months 3 and 6 for ximelagatran (p = .0453, p = .0014, respectively). ASAT and ASAT/ALAT ratio values did not increase and not differ for both groups. In the THRIVE III trial, ALAT and ASAT did not increase and did not differ compared to the comparator placebo. 2 x 36 mg Ximelagatran, induced higher ALAT values at months 3 and 6 compared to 2 x 24 mg ximelagatran (p = .0105, p = .0063, respectively). ASAT did not differ between the two doses of ximelagatran. The ASAT/ALAT ratios were lower at week 2 for enoxaparin/warfarin (t-test, p = .0032) and at month 3 and 6 for 2 x 36 mg versus warfarin or 2 x 24 mg Ximelagatran (p between .0187 and .0002). The authors conclude that ALAT increases dose dependently during therapy with ximelagatran. The less frequent and lower increase of ASAT values compared to ALAT values indicates a nontoxic effect of ximelagatran on liver cells.

  8. Insulin resistance is associated with elevated transaminases and low aspartate aminotransferase/alanine aminotransferase ratio in young adults with normal weight.

    PubMed

    Simental-Mendía, Luis E; Rodríguez-Morán, Martha; Gómez-Díaz, Rita; Wacher, Niels H; Rodríguez-Hernández, Heriberto; Guerrero-Romero, Fernando

    2017-04-01

    The aim of this study is to determine whether insulin resistance is associated with elevation of transaminases levels and aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio in normal-weight healthy young adults. Apparently healthy nonpregnant women and men, aged 18-23 years, were enrolled in a cross-sectional study. According to the homeostasis model assessment of insulin resistance, the participants were allocated into groups of patients with (>2.5) and without (≤2.5) insulin resistance. Normal weight was defined by BMI of at least 18.5 and less than 25.0 kg/m. A multiple logistic regression analysis was carried out to determine the association between insulin resistance and elevated transaminases and AST/ALT ratio of 1 or less. A total of 1732 young adults were enrolled and allocated into groups with (n=287) and without (n=1445) insulin resistance. The prevalence of insulin resistance was 16.6% in the overall population. The multivariate logistic regression analysis adjusted by age, sex, waist circumference, and BMI indicated that the odds ratio (OR) between insulin resistance and elevated ALT concentrations is 1.65 [95% confidence interval (CI): 1.04-2.62, P=0.03], for AST/ALT ratio lower than 1 OR is 1.69 (95% CI: 1.27-2.26, P<0.001), and for elevated AST levels OR is 1.31 (95% CI: 0.71-2.43, P=0.377). The results of the present study suggest that insulin resistance is significantly associated with elevated ALT levels and AST/ALT ratio of lower than 1, but not with elevated AST levels.

  9. Serum Alanine Aminotransferase Levels, Hematocrit Rate and Body Weight Correlations Before and After Hemodialysis Session

    PubMed Central

    Lopes, Edmundo Pessoa; Sette, Luis Henrique B. C.; Sette, Jorge Bezerra C.; Luna, Carlos F.; Andrade, Amaro M.; Moraes, Maviael; Sette, Paulo C. A.; Menezes, Roberto; Cavalcanti, Rui L.; Conceição, Sergio C.

    2009-01-01

    PURPOSE To evaluate alanine aminotransferase levels before and after a hemodialysis session and to correlate these values with the hematocrit rate and weight loss during hemodialysis. PATIENTS AND METHODS The serum alanine aminotransferase levels, hematocrit rate and body weight were measured and correlated before and after a single hemodialysis session for 146 patients with chronic renal failure. An receiver operating characteristic (ROC) curve for the serum alanine aminotransferase levels collected before and after hemodialysis was plotted to identify hepatitis C virus-infected patients. RESULTS The mean weight loss of the 146 patients during hemodialysis was 5.3% (p < 0.001). The mean alanine aminotransferase levels before and after hemodialysis were 18.8 and 23.9 IU/, respectively, denoting a significant 28.1% increase. An equally significant increase of 16.4% in the hematocrit rate also occurred after hemodialysis. The weight loss was inversely correlated with the rise in both the alanine aminotransferase level (r = 0.3; p < 0.001) and hematocrit rate (r = 0.5; p < 0.001). A direct correlation was found between the rise in alanine aminotransferase levels and the hematocrit during the hemodialysis session (r = 0.4; p < 0.001). Based on the ROC curve, the upper limit of the normal alanine aminotransferase level should be reduced by 40% relative to the upper limit of normal if the blood samples are collected before the hemodialysis session or by 60% if blood samples are collected after the session. CONCLUSION In the present study, significant elevations in the serum alanine aminotransferase levels and hematocrit rates occurred in parallel to a reduction in body weight after the hemodialysis session. These findings suggest that one of the factors for low alanine aminotransferase levels prior to hemodialysis could be hemodilution in patients with chronic renal failure. PMID:19841699

  10. Ethanol reduces lifespan, body weight, and serum alanine aminotransferase level of aldehyde dehydrogenase 2 knockout mouse.

    PubMed

    Matsumoto, Akiko; Vasiliou, Vasilis; Kawamoto, Toshihiro; Tanaka, Keitaro; Ichiba, Masayoshi

    2014-07-01

    The aldehyde dehydrogenase 2 (Aldh2) knockout mouse is an animal model of a polymorphism at the human ALDH2 locus (ALDH2*2). To detect differences in the basic phenotype of this animal model, lifespan, body weight (BW), and serum alanine aminotransferase (ALT) level were evaluated. Aldh2(+/+) , Aldh2(+/-) , and Aldh2(-/-) mice were maintained, from 10 weeks of age, on standard solid food, with liquid supplied as ethanol (EtOH) solution at a concentration of 0 to 20% (forced EtOH consumption). For animals provided with water (without EtOH), mice of the distinct genotypes exhibited no difference in lifespan, with the mean values ranging from 90 to 96 weeks for female mice and 97 to 105 weeks for male mice. For animals provided with EtOH, there was a dose-dependent reduction of lifespan in Aldh2(-/-) mice with p for trend <0.001. For example, the mean lifespans of the Aldh2(-/-) females in the 0, 3, 10, and 20% groups were 95, 85, 70, and 29 weeks, respectively. No influence on lifespan was found for Aldh2(+/+) and Aldh2(+/-) mice. BW and ALT level of Aldh2(-/-) mice were significantly lower than those of Aldh2(+/+) mice when the mice were treated with EtOH. While multiple regression analysis suggested that the BW and ALT level in Aldh2(-/-) mice correlated with lifespan, adjustment for EtOH concentration revealed that this correlation was not significant (i.e., reflected EtOH dependence). Aldh2(-/-) mice were unchanged in terms of their basic phenotype under standard laboratory conditions. However, chronic EtOH administration (forced consumption) in these mice resulted in dose-dependent reductions in lifespan, BW, and serum ALT level. Copyright © 2014 by the Research Society on Alcoholism.

  11. Effect of low-zinc status and essential fatty acids deficiency on the activities of aspartate aminotransferase and alanine aminotransferase in liver and serum of albino rats.

    PubMed

    Ajayi, Olubunmi Bolanle; Odutuga, Adewale

    2004-04-01

    The effects of dietary deficiencies of zinc and essential fatty acids (EFAs) or both on aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were investigated in young growing rats. Four groups of albino rats were fed diets deficient in either EFA (4% hydrogenated coconut oil) or zinc (6 ppm) or both. The control diet was adequate in EFA (4% soybean oil) and zinc (100 ppm). The feeding trial lasted eight weeks and the activities of AST and ALT were determined in the liver and serum. EFA deficiency had no significant (p > 0.05) effect on liver AST. However, zinc and the double deficiencies depressed AST activity in the organ. Deficiencies of EFA, zinc and their combination depressed ALT activity in the liver significantly (p < 0.05) with a concomitant increase recorded in the serum. The data suggested alteration in endothelial permeability of the plasma membrane and thus leakage of membrane constituents in the tissue studied. It is therefore considered that these deficient diets may affect liver tissue negatively in view of the role of these enzymes in amino acid metabolism.

  12. Dose-Response Relationship between Alanine Aminotransferase Levels within the Reference Interval and Metabolic Syndrome in Chinese Adults

    PubMed Central

    Wu, Peipei; Chen, Qicai; Chen, Lili; Zhang, Pengpeng; Xiao, Juan; Chen, Xiaoxiao; Liu, Meng

    2017-01-01

    Purpose Elevation in serum alanine aminotransferase (ALT) levels is a biomarker for metabolic syndrome (MS); however, the relationship has not been fully investigated within the reference interval of ALT levels. Our objective was to explore the relationship between serum ALT levels within the reference interval and MS in Chinese adults. Materials and Methods This cross-sectional study included 16028 adults, who attended routine health check-ups at Shengli Oilfield Central Hospital from January 2006 to March 2012. The reference interval of serum ALT level was defined as less than 40 U/L. Logistic regression models and restricted cubic spline were used to evaluate the association of ALT with MS. Results The prevalence of MS in the total population was 13.7% (6.4% for females and 18.4% for males). Multiple logistic regression showed that ALT levels were positively associated with MS after adjustment for potential confounding factors. The odds ratio of MS in the top quartile was 4.830 [95% confidence interval (CI): 2.980–7.829] in females and 3.168 (95% CI: 2.649–3.790) in males, compared with the ALT levels in the bottom quartile. The restricted cubic spline models revealed a positive non-linear dose-response relationship between ALT levels and the risk of MS in women (p for nonlinearity was 0.0327), but a positive linear dose-response relationship in men (p for nonlinearity was 0.0659). Conclusion Serum ALT levels within the reference interval are positively associated with MS in a dose-response manner. Elevated ALT levels, even within the reference interval, may reflect early dysmetabolic changes. PMID:27873509

  13. Elevated Aspartate and Alanine Aminotransferase Levels and Natural Death among Patients with Methamphetamine Dependence

    PubMed Central

    Kuo, Chian-Jue; Tsai, Shang-Ying; Liao, Ya-Tang; Conwell, Yeates; Lee, Wen-Chung; Huang, Ming-Chyi; Lin, Shih-Ku; Chen, Chiao-Chicy; Chen, Wei J.

    2012-01-01

    Background Methamphetamine is one of the fastest growing illicit drugs worldwide, causing multiple organ damage and excessive natural deaths. The authors aimed to identify potential laboratory indices and clinical characteristics associated with natural death through a two-phase study. Methods Methamphetamine-dependent patients (n = 1,254) admitted to a psychiatric center in Taiwan between 1990 and 2007 were linked with a national mortality database for causes of death. Forty-eight subjects died of natural causes, and were defined as the case subjects. A time-efficient sex- and age-matched nested case-control study derived from the cohort was conducted first to explore the potential factors associated with natural death through a time-consuming standardized review of medical records. Then the identified potential factors were evaluated in the whole cohort to validate the findings. Results In phase I, several potential factors associated with natural death were identified, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), comorbid alcohol use disorder, and the prescription of antipsychotic drugs. In phase II, these factors were confirmed in the whole cohort using survival analysis. For the characteristics at the latest hospital admission, Cox proportional hazards models showed that the adjusted hazard ratios for natural death were 6.75 (p<0.001) in the group with markedly elevated AST (>80 U/L) and 2.66 (p<0.05) in the group with mildly elevated AST (40–80 U/L), with reference to the control group (<40 U/L). As for ALT, the adjusted hazard ratios were 5.41 (p<0.001), and 1.44 (p>0.05). Comorbid alcohol use disorder was associated with an increased risk of natural death, whereas administration of antipsychotic drugs was not associated with lowered risk. Conclusions This study highlights the necessity of intensive follow-up for those with elevated AST and ALT levels and comorbid alcohol use disorder for preventing excessive natural

  14. Ceruloplasmin, a reliable marker of fibrosis in chronic hepatitis B virus patients with normal or minimally raised alanine aminotransferase

    PubMed Central

    Zeng, Da-Wu; Dong, Jing; Jiang, Jia-Ji; Zhu, Yue-Yong; Liu, Yu-Rui

    2016-01-01

    AIM To develop a non-invasive model to evaluate significant fibrosis and cirrhosis by investigating the association between serum ceruloplasmin (CP) levels and liver fibrosis in chronic hepatitis B (CHB) patients with normal or minimally raised alanine aminotransferase (ALT). METHODS Serum samples and liver biopsy were obtained from 193 CHB patients with minimally raised or normal ALT who were randomly divided into a training group (n = 97) and a validation group (n = 96). Liver histology was evaluated by the METAVIR scoring system. Receiver operator characteristic curves were applied to the diagnostic value of CP for measuring liver fibrosis in CHB patients. Spearman rank correlation analyzed the relationship between CP and liver fibrosis. A non-invasive model was set up through multivariate logistic regression analysis. RESULTS Serum CP levels individualized various fibrosis stages via area under the curve (AUC) values. Multivariate analysis revealed that CP levels were significantly related to liver cirrhosis. Combining CP with serum GGT levels, a CG model was set up to predict significant fibrosis and liver cirrhosis in CHB patients with normal or minimally raised ALT. The AUC, sensitivity, specificity, positive predictive value, and negative predictive value were 0.84, 83.1%, 78.6%, 39.6%, and 96.5% to predict liver cirrhosis, and 0.789, 80.26%, 68.38%, 62.25%, and 84.21% to predict significant fibrosis. This model expressed a higher AUC than FIB-4 (age, ALT, aspartate aminotransferase, platelets) and GP (globulin, platelets) models to predict significant fibrosis (P = 0.019 and 0.022 respectively) and revealed a dramatically greater AUC than FIB-4 (P = 0.033) to predict liver cirrhosis. CONCLUSION The present study showed that CP was independently and negatively associated with liver fibrosis. Furthermore, we developed a novel promising model (CG), based on routine serum markers, for predicting liver fibrosis in CHB patients with normal or minimally raised

  15. Histological features and HLA class II alleles in hepatitis C virus chronically infected patients with persistently normal alanine aminotransferase levels.

    PubMed

    Renou, C; Halfon, P; Pol, S; Cacoub, P; Jouve, E; Bronowicki, J P; Arpurt, J P; Rifflet, H; Picon, M; Causse, X; Canva, V; Denis, J; Tran, A; Bourliére, M; Ouzan, D; Pariente, A; Dantin, S; Alric, L; Cartier, V; Reville, M; Caillat-Zucman, S

    2002-10-01

    A significant proportion of individuals with chronic hepatitis C virus (HCV) infection have persistently normal alanine aminotransferase (ALT) levels. Although data are controversial, such patients usually have weaker histological damage and a lower progression rate of fibrosis. The aims of this study were: (1) to compare demographic, virological, and histological parameters of HCV patients with normal ALT values with those of HCV patients with elevated ALT levels; and (2) to determine whether HLA class II alleles contribute to the persistence of normal ALT levels in HCV patients. Eighty three patients with chronic HCV infection and persistently normal ALT values (group 1) and 233 patients with chronic HCV infection and elevated ALT levels (group 2) were studied. Histological features were expressed using Knodell and Metavir scores. HLA DRB1* and DQB1* genotyping was performed using hybridisation with sequence specific oligonucleotides after genomic amplification. The kappa2 and Fisher's exact tests were used to compare discrete variables and phenotype frequencies between the two groups, and Wilcoxon's test was used for continuous variables. A multivariate logistic regression model was used to determine which variables predicted normal ALT values. ALT levels were correlated with the severity of liver damage. In group 1, 93% of patients had an F0 or F1 Metavir index of fibrosis compared with 47% of patients in group 2 (p<0.001). A longer duration of infection (p<0.001) and increased DRB1*11 phenotype frequency (pc=0.03) were observed among patients with normal ALT. The two groups did not differ with regard to the mode of contamination or viral genotype. After logistic regression, young age (p=0.0008), female sex (p=0.01), long duration of infection (p=0.0001), and HLA DRB1*11 (p=0.050) were more strongly associated with persistence of normal ALT. Our study confirms that patients with chronic hepatitis C and normal ALT levels have less severe liver disease than those

  16. [Levels of aspartate aminotransferase and alanine aminotransferase in two factories with various hepato-toxic risks].

    PubMed

    Bavazzano, P; Benassi, S; Forzieri, R; Petrioli, G

    1981-12-01

    The Authors have studied AST and ALT enzymatic activities in the workers of two firms, the former of which (tannery) with a high and the latter (boot and shoe factory) with a low level of hepatic-toxic risk. The influence of various trouble factors such as age, sex and seniority was eliminated through appropriate statistical techniques. A significant difference was evidenced between AST and ALT levels in two firms, chiefly attributable to the quantity and quality of the substances utilized in the two technological cycles: trichloroethylene, chromium, sulphuric acid, mineral oils, ammonia, N-hexane, pentanes acetone, ciclo hexane, methanol, ethyl acetate, isopropyl acetate, toluene, methylene chloride.

  17. Effect of Caffeine-Containing Beverage Consumption on Serum Alanine Aminotransferase Levels in Patients with Chronic Hepatitis C Virus Infection: A Hospital-Based Cohort Study

    PubMed Central

    Sasaki, Yachiyo; Ohfuji, Satoko; Fukushima, Wakaba; Tamori, Akihiro; Enomoto, Masaru; Habu, Daiki; Iwai, Shuji; Uchida-Kobayashi, Sawako; Fujii, Hideki; Shiomi, Susumu; Kawada, Norifumi; Hirota, Yoshio

    2013-01-01

    Introduction To date, there have been no prospective studies examining the effect of coffee consumption on serum alanine aminotransferase (ALT) level among individuals infected with the hepatitis C virus (HCV). We conducted a hospital-based cohort study among patients with chronic HCV infection to assess an association between baseline coffee consumption and subsequent ALT levels for 12 months. Materials and Methods From 1 August 2005 to 31 July 2006, total 376 HCV-RNA positive patients were recruited. A baseline questionnaire elicited information on the frequency of coffee consumption and other caffeine-containing beverages. ALT level as a study outcome was followed through the patients’ medical records during 12 months. The association between baseline beverage consumption and subsequent ALT levels was evaluated separately among patients with baseline ALT levels within normal range (≤45 IU/L) and among those with higher ALT levels (>45 IU/L). Results Among 229 patients with baseline ALT levels within normal range, 186 (81%) retained normal ALT levels at 12 months after recruitment. Daily drinkers of filtered coffee were three times more likely to preserve a normal ALT level than non-drinkers (OR=2.74; P=0.037). However, decaffeinated coffee drinkers had a somewhat inverse effect for sustained normal ALT levels, with marginal significance (OR=0.26; P=0.076). In addition, among 147 patients with higher baseline ALT levels, 39 patients (27%) had ALT reductions of ≥20 IU/L at 12 months after recruitment. Daily drinkers of filtered coffee had a significantly increased OR for ALT reduction (OR=3.79; P=0.034). However, in decaffeinated coffee drinkers, OR could not be calculated because no patients had ALT reduction. Conclusion Among patients with chronic HCV infection, daily consumption of filtered coffee may have a beneficial effect on the stabilization of ALT levels. PMID:24349501

  18. Effect of caffeine-containing beverage consumption on serum alanine aminotransferase levels in patients with chronic hepatitis C virus infection: a hospital-based cohort study.

    PubMed

    Sasaki, Yachiyo; Ohfuji, Satoko; Fukushima, Wakaba; Tamori, Akihiro; Enomoto, Masaru; Habu, Daiki; Iwai, Shuji; Uchida-Kobayashi, Sawako; Fujii, Hideki; Shiomi, Susumu; Kawada, Norifumi; Hirota, Yoshio

    2013-01-01

    To date, there have been no prospective studies examining the effect of coffee consumption on serum alanine aminotransferase (ALT) level among individuals infected with the hepatitis C virus (HCV). We conducted a hospital-based cohort study among patients with chronic HCV infection to assess an association between baseline coffee consumption and subsequent ALT levels for 12 months. From 1 August 2005 to 31 July 2006, total 376 HCV-RNA positive patients were recruited. A baseline questionnaire elicited information on the frequency of coffee consumption and other caffeine-containing beverages. ALT level as a study outcome was followed through the patients' medical records during 12 months. The association between baseline beverage consumption and subsequent ALT levels was evaluated separately among patients with baseline ALT levels within normal range (≤45 IU/L) and among those with higher ALT levels (>45 IU/L). Among 229 patients with baseline ALT levels within normal range, 186 (81%) retained normal ALT levels at 12 months after recruitment. Daily drinkers of filtered coffee were three times more likely to preserve a normal ALT level than non-drinkers (OR=2.74; P=0.037). However, decaffeinated coffee drinkers had a somewhat inverse effect for sustained normal ALT levels, with marginal significance (OR=0.26; P=0.076). In addition, among 147 patients with higher baseline ALT levels, 39 patients (27%) had ALT reductions of ≥20 IU/L at 12 months after recruitment. Daily drinkers of filtered coffee had a significantly increased OR for ALT reduction (OR=3.79; P=0.034). However, in decaffeinated coffee drinkers, OR could not be calculated because no patients had ALT reduction. Among patients with chronic HCV infection, daily consumption of filtered coffee may have a beneficial effect on the stabilization of ALT levels.

  19. High alanine aminotransferase is associated with decreased hepatic insulin sensitivity and predicts the development of type 2 diabetes.

    PubMed

    Vozarova, Barbora; Stefan, Norbert; Lindsay, Robert S; Saremi, Aramesh; Pratley, Richard E; Bogardus, Clifton; Tataranni, P Antonio

    2002-06-01

    It has been proposed that liver dysfunction may contribute to the development of type 2 diabetes. The aim of the present study was to examine whether elevated hepatic enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], or gamma -glutamyltranspeptidase [GGT]) are associated with prospective changes in liver or whole-body insulin sensitivity and/or insulin secretion and whether these elevated enzymes predict the development of type 2 diabetes in Pima Indians. We measured ALT, AST, and GGT in 451 nondiabetic (75-g oral glucose tolerance test) Pima Indians (aged 30 +/- 6 years, body fat 33 +/- 8%, ALT 45 +/- 29 units/l, AST 34 +/- 18 units/l, and GGT 56 +/- 40 units/l [mean +/- SD]) who were characterized for body composition (hydrodensitometry or dual-energy X-ray absorptiometry), whole-body insulin sensitivity (M), and hepatic insulin sensitivity (hepatic glucose output [HGO] during the low-dose insulin infusion of a hyperinsulinemic clamp) and acute insulin response (AIR) (25-g intravenous glucose challenge). Sixty-three subjects developed diabetes over an average follow-up of 6.9 +/- 4.9 years. In 224 subjects, who remained nondiabetic, follow-up measurements of M and AIR were available. At baseline, ALT, AST, and GGT were related to percent body fat (r = 0.16, 0.17, and 0.11, respectively), M (r = -0.32, - 0.28, and -0.24), and HGO (r = 0.27, 0.12, and 0.14; all P < 0.01). In a proportional hazard analysis with adjustment for age, sex, body fat, M, and AIR, higher ALT [relative hazard 90th vs. 10th centiles (95% CI): 1.9 (1.1-3.3), P = 0.02], but not AST or GGT, predicted diabetes. Elevated ALT at baseline was associated prospectively with an increase in HGO (r = 0.21, P = 0.001) but not with changes in M or AIR (both P = 0.1). Higher ALT concentrations were cross-sectionally associated with obesity and whole-body and hepatic insulin resistance and prospectively associated with a decline in hepatic insulin sensitivity and the development of

  20. Factors Associated With Persistent Increase in Level of Alanine Aminotransferase in Patients With Chronic Hepatitis B Receiving Oral Antiviral Therapy.

    PubMed

    Jacobson, Ira M; Washington, Mary K; Buti, Maria; Thompson, Alexander; Afdhal, Nezam; Flisiak, Robert; Akarca, Ulus Salih; Tchernev, Konstantin G; Flaherty, John F; Aguilar Schall, Raul; Myers, Robert P; Subramanian, G Mani; McHutchison, John G; Younossi, Zobair; Marcellin, Patrick; Patel, Keyur

    2017-07-01

    Despite complete suppression of viral DNA with antiviral agents, in some patients with chronic hepatitis B (CHB), serum levels of alanine aminotransferase (ALT) do not normalize. We investigated factors associated with persistent increases in ALT level in patients with CHB given long-term tenofovir disoproxil fumarate. We analyzed data from 471 hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients with CHB participating in 2 phase 3 trials. We identified patients with an increased level of ALT (above the upper limit of normal range) after 5 years (240 weeks) of tenofovir disoproxil fumarate therapy. We analyzed findings from liver biopsy specimens collected from 467 patients (99%) at baseline and 339 patients (72%) at year 5 of treatment; biopsy specimens were evaluated by an independent pathologist. We performed stepwise, forward, multivariate regression analyses of specified baseline characteristics and on-treatment response parameters to identify factors associated with persistent increases in ALT level. Of the 471 patients, 87 (18%) still had an increased ALT level at year 5 of treatment. Factors associated significantly with a persistent increase in ALT level were a steatosis score of 5% or greater (grade 1 or more) at baseline (odds ratio [OR], 2.236; 95% confidence interval [CI], 1.031-4.852; P = .042) and at year 5 (OR, 3.392; 95% CI, 1.560 ≥ 7.375; P = .002), HBeAg seropositivity at baseline (OR, 3.297; 95% CI, 1.653-6.576; P < .001), and age 40 years or older (OR, 2.099; 95% CI, 1.014-4.342; P = .046). Of the 42 HBeAg-positive patients with steatosis at baseline, 21 (50%) had an increased ALT level at year 5 of treatment. Patients with persistent increases in ALT level were more likely to have an increase in steatosis at year 5 than those with a normal ALT level. HBeAg seropositivity and hepatic steatosis contribute to persistent increases in ALT level in patients with CHB receiving suppressive antiviral treatment. Clinical

  1. Interaction between obesity and the Hypoxia Inducible Factor 3 Alpha Subunit rs3826795 polymorphism in relation with plasma alanine aminotransferase.

    PubMed

    Wang, Shuo; Song, Jieyun; Yang, Yide; Zhang, Yining; Chawla, Nitesh V; Ma, Jun; Wang, Haijun

    2017-07-28

    Hypoxia Inducible Factor 3 Alpha Subunit (HIF3A) DNA has been demonstrated to be associated with obesity in the methylation level, and it also has a Body Mass Index (BMI)-independent association with plasma alanine aminotransferase (ALT). However, the relation among obesity, plasma ALT, HIF3A polymorphism and methylation remains unclear. This study aims to identify the association between HIF3A polymorphism and plasma ALT, and further to determine whether the effect of HIF3A polymorphism on ALT could be modified by obesity or mediated by DNA methylation. The HIF3A rs3826795 polymorphism was genotyped in a case-control study including 2030 Chinese children aged 7-18 years (705 obese cases and 1325 non-obese controls). Furthermore, the HIF3A DNA methylation of the peripheral blood was measured in 110 severely obese children and 110 age- and gender- matched normal-weight controls. There was no overall association between the HIF3A rs3826795 polymorphism and ALT. A significant interaction between obesity and rs3826795 in relation with ALT was found (P inter = 0.042), with rs3826795 G-allele number elevating ALT significantly only in obese children (β' = 0.075, P = 0.037), but not in non-obese children (β' = -0.009, P = 0.741). Additionally, a mediation effect of HIF3A methylation was found in the association between the HIF3A rs3826795 polymorphism and ALT among obese children (β' = 0.242, P = 0.014). This is the first study to report the interaction between obesity and HIF3A gene in relation with ALT, and also to reveal a mediation effect among the HIF3A polymorphism, methylation and ALT. This study provides new evidence to the function of HIF3A gene, which would be helpful for future risk assessment and personalized treatment of liver diseases.

  2. SAFETY study: Alanine aminotransferase cutoff values are set too high for reliable detection of pediatric chronic liver disease

    PubMed Central

    Schwimmer, Jeffrey B.; Dunn, Winston; Norman, Gregory J.; Pardee, Perrie E.; Middleton, Michael S.; Kerkar, Nanda; Sirlin, Claude B.

    2010-01-01

    Background & Aims The appropriate alanine aminotransferase (ALT) threshold value to use for diagnosis of chronic liver disease in children is unknown. We sought to develop sex-specific, biology-based, pediatric ALT thresholds. Methods The screening ALT for elevation in today’s youth (SAFETY) study collected observational data from acute care children’s hospitals, the national health and nutrition examination survey (NHANES, 1999–2006), overweight children with and without non-alcoholic fatty liver disease (NAFLD), and children with chronic Hepatitis B virus (HBV) or Hepatitis C virus (HCV) infections. The study compared the sensitivity and specificity of ALT thresholds currently used by children’s hospitals versus study-derived, sex-specific, biology-based, ALT thresholds for detecting children with NAFLD, HCV, or HBV. Results The median upper limit of ALT at children’s hospitals was 53 U/L (range, 30–90). The 95th percentile levels for ALT in healthy weight, metabolically normal, liver disease-free, NHANES pediatric participants were 25.8 U/L (boys) and 22.1 U/L (girls). The concordance statistics of these NHANES-derived thresholds for liver disease detection were 0.85 (95% confidence interval [CI] 0.74–0.96) in boys and 0.91 (95% CI 0.83–0.99) in girls for NAFLD, 0.80 (95% CI 0.70–0.91) in boys and 0.79 (95% CI 0.69–0.89) in girls for HBV, and 0.86 (95% CI 0.77–0.95) in boys and 0.84 (95% CI 0.75–0.93) in girls for HCV. Using current children’s hospitals ALT thresholds, the median sensitivity for detection of NAFLD, HBV, and HCV ranged from 32% to 48%; median specificity was 92% (boys) and 96% (girls). Using NHANES-derived thresholds, the sensitivities were 72% (boys) and 82% (girls); specificities were 79% (boys) and 85% (girls). Conclusions The upper limit of ALT used in children’s hospitals varies widely and is set too high to reliably detect chronic liver disease. Biology-based thresholds provide higher sensitivity and only

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

    DOEpatents

    Jessen, Holly Jean [Chanhassen, MN; Liao, Hans H [Eden Prairie, MN; Gort, Steven John [Apple Valley, MN; Selifonova, Olga V [Plymouth, MN

    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.

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

    SciTech Connect

    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.

  5. 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 Chemistry...

  6. 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 Chemistry...

  7. 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 Chemistry...

  8. 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 Chemistry...

  9. 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 Chemistry...

  10. 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

  11. Identification and expression analyses of the alanine aminotransferase (AlaAT) gene family in poplar seedlings

    PubMed Central

    Xu, Zhiru; Ma, Jing; Qu, Chunpu; Hu, Yanbo; Hao, Bingqing; Sun, Yan; Liu, Zhongye; Yang, Han; Yang, Chengjun; Wang, Hongwei; Li, Ying; Liu, Guanjun

    2017-01-01

    Alanine aminotransferase (AlaAT, E.C.2.6.1.2) catalyzes the reversible conversion of pyruvate and glutamate to alanine and α-oxoglutarate. The AlaAT gene family has been well studied in some herbaceous plants, but has not been well characterized in woody plants. In this study, we identified four alanine aminotransferase homologues in Populus trichocarpa, which could be classified into two subgroups, A and B. AlaAT3 and AlaAT4 in subgroup A encode AlaAT, while AlaAT1 and AlaAT2 in subgroup B encode glutamate:glyoxylate aminotransferase (GGAT), which catalyzes the reaction of glutamate and glyoxylate to α-oxoglutarate and glycine. Four AlaAT genes were cloned from P. simonii × P. nigra. PnAlaAT1 and PnAlaAT2 were expressed predominantly in leaves and induced by exogenous nitrogen and exhibited a diurnal fluctuation in leaves, but was inhibited in roots. PnAlaAT3 and PnAlaAT4 were mainly expressed in roots, stems and leaves, and was induced by exogenous nitrogen. The expression of PnAlaAT3 gene could be regulated by glutamine or its related metabolites in roots. Our results suggest that PnAlaAT3 gene may play an important role in nitrogen metabolism and is regulated by glutamine or its related metabolites in the roots of P. simonii × P. nigra. PMID:28378825

  12. Identification and expression analyses of the alanine aminotransferase (AlaAT) gene family in poplar seedlings.

    PubMed

    Xu, Zhiru; Ma, Jing; Qu, Chunpu; Hu, Yanbo; Hao, Bingqing; Sun, Yan; Liu, Zhongye; Yang, Han; Yang, Chengjun; Wang, Hongwei; Li, Ying; Liu, Guanjun

    2017-04-05

    Alanine aminotransferase (AlaAT, E.C.2.6.1.2) catalyzes the reversible conversion of pyruvate and glutamate to alanine and α-oxoglutarate. The AlaAT gene family has been well studied in some herbaceous plants, but has not been well characterized in woody plants. In this study, we identified four alanine aminotransferase homologues in Populus trichocarpa, which could be classified into two subgroups, A and B. AlaAT3 and AlaAT4 in subgroup A encode AlaAT, while AlaAT1 and AlaAT2 in subgroup B encode glutamate:glyoxylate aminotransferase (GGAT), which catalyzes the reaction of glutamate and glyoxylate to α-oxoglutarate and glycine. Four AlaAT genes were cloned from P. simonii × P. nigra. PnAlaAT1 and PnAlaAT2 were expressed predominantly in leaves and induced by exogenous nitrogen and exhibited a diurnal fluctuation in leaves, but was inhibited in roots. PnAlaAT3 and PnAlaAT4 were mainly expressed in roots, stems and leaves, and was induced by exogenous nitrogen. The expression of PnAlaAT3 gene could be regulated by glutamine or its related metabolites in roots. Our results suggest that PnAlaAT3 gene may play an important role in nitrogen metabolism and is regulated by glutamine or its related metabolites in the roots of P. simonii × P. nigra.

  13. How to manage HBeAg-negative chronic HBV infection with normal alanine aminotransferase levels in clinical practice?

    PubMed

    Puoti, Claudio

    2013-03-01

    Many HBsAg-positive/HBeAg-negative patients show normal alanine aminotransferase levels. However, in this group of patients two different virological and clinical subsets do exist: inactive HBV carriers and patients with chronic hepatitis B with transient virological and biochemical remission. Natural history and outcome, severity of liver damage and need for liver biopsy and antiviral treatment differ significantly between these groups of patients. It is not always easy to distinguish between inactive HBV carriers and patients suffering from HBeAg-negative chronic hepatitis with transient disease remission, as they share similar biochemical (normal serum ALT values) and virological (HBeAg negativity and low HBV DNA levels) features. In clinical practice, it is very important to differentiate inactive carriers from patients with chronic hepatitis B with spontaneous transient remission, as the former have a good prognosis with a very low risk of complications, while the latter have active liver disease with a high risk of progression to advanced hepatic fibrosis, cirrhosis and hepatocellular carcinoma. Thus, a careful assessment and adequate follow-up periods are needed. The aim of this review, written in the form of a dialog between a hepatologist and a newly diagnosed patient with HBV infection and normal alanine aminotransferase levels, is to give evidence-based suggestions for the management in clinical practice of HBsAg patients, on the basis of more recent international guidelines, covering many aspects of the condition, including advice on lifestyle and vaccination, indications for liver biopsy and treatment, the types and side effects of treatment and treatment endpoints. Copyright © 2012 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  14. Trihalomethane exposure and biomonitoring for the liver injury indicator, alanine aminotransferase, in the United States population (NHANES 1999–2006)

    PubMed Central

    Burch, James B.; Everson, Todd M.; Seth, Ratanesh K.; Wirth, Michael D.; Chatterjee, Saurabh

    2015-01-01

    Exposure to trihalomethanes (or THMs: chloroform, bromoform, bromodichloromethane, and dibromochloromethane [DBCM]) formed via drinking water disinfection has been associated with adverse reproductive outcomes and cancers of the digestive or genitourinary organs. However, few studies have examined potential associations between THMs and liver injury in humans, even though experimental studies suggest that these agents exert hepatotoxic effects, particularly among obese individuals. This study examined participants in the National Health and Nutrition Examination Survey (1999–2006, N = 2781) to test the hypothesis that THMs are associated with liver injury as assessed by alanine aminotransferase (ALT) activity in circulation. Effect modification by body mass index (BMI) or alcohol consumption also was examined. Associations between blood THM concentrations and ALT activity were assessed using unconditional multiple logistic regression to calculate prevalence odds ratios (ORs) with 95% confidence intervals (CIs) for exposure among cases with elevated ALT activity (men: >40 IU/L, women: >30 IU/L) relative to those with normal ALT, after adjustment for variables that may confound the relationship between ALT and THMs. Compared to controls, cases were 1.35 times more likely (95% CI: 1.02, 1.79) to have circulating DBCM concentrations exceeding median values in the population. There was little evidence for effect modification by BMI, although the association varied by alcohol consumption. Among non-drinkers, cases were more likely than controls to be exposed to DBCM (OR: 3.30, 95% CI: 1.37–7.90), bromoform (OR: 2.88, 95% CI: 1.21–6.81), or brominated THMs (OR: 4.00, 95% CI: 1.31–12.1), but no association was observed among participants with low, or moderate to heavy alcohol consumption. Total THM levels exceeding benchmark exposure limits continue to be reported both in the United States and globally. Results from this study suggest a need for further

  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. PMID:27182252

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

    PubMed

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

    2016-01-01

    To evaluate the associations between adverse perinatal outcomes and serum transaminase levels at the time of diagnosis in patients with intrahepatic cholestasis of pregnancy. 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). 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. Patients with intrahepatic cholestasis of pregnancy and high alanineaminotransferase levels should be followed up for possible adverse perinatal outcomes.

  17. Plasma sphingolipids as potential indicators of hepatic necroinflammation in patients with chronic hepatitis C and normal alanine aminotransferase level.

    PubMed

    Li, Jun-Feng; Qu, Feng; Zheng, Su-Jun; Ren, Jin-Yu; Wu, Hui-Li; Liu, Mei; Liu, Hui; Ren, Feng; Chen, Yu; Zhang, Jin-Lan; Duan, Zhong-Ping

    2014-01-01

    Accurate estimation of hepatic necroinflammation caused by chronic hepatitis C (CHC) is crucial for prediction of prognosis and design of therapeutic strategy, which is particularly true for CHC patients with normal alanine aminotransferase (ALT) level. Recent studies have shown that sphingolipids have a close relationship with hepatitis C virus infection. The present study aimed to identify plasma sphingolipids related to hepatic necroinflammation. We included 120 treatment-naïve CHC patients and 64/120 had normal ALT levels (<40 U/L). CHC patients who underwent liver biopsies were subjected to Scheuer scoring analysis for scope of hepatic inflammation. Plasma sphingolipids were detected by high-performance liquid chromatography tandem mass spectrometry. Our results showed 44 plasma sphingolipids were detected altogether. Of all detected sphingolipids, hexosylceramide (HexCer) (d18∶1/22∶0) and HexCer (d18∶1/24∶0) showed a significant difference among G0/G1, G2, and G3/G4 (P<0.05). For identifying hepatic necroinflammation (G≥2), after adjusting other factors, the odds ratio (OR) of HexCer (d18∶1/22∶0) reached 1.01 (95% confidence interval [CI]: 1.00-1.02). Furthermore, the area under the curve (AUC) of HexCer (d18∶1/22∶0) was 0.7 (P = 0.01) and approached that of ALT (AUC = 0.78). However, in CHC patients with normal ALT, HexCer (d18∶1/22∶0) was an independent factor (OR: 1.02, 95% CI: 1.01-1.03) to identify the hepatic necroinflammation (G≥2). HexCer (d18∶1/22∶0) not only showed the largest AUC (0.78, P = 0.001), but also exhibited the highest specificity of all indicators. These results indicate that plasma HexCer (d18∶1/22∶0) is a potential indicator to distinguish hepatic necroinflammation in CHC patients. For CHC with normal ALT, the ability of HexCer (d18∶1/22∶0) to distinguish hepatic necroinflammation might be superior to conventional serum indicators.

  18. Plasma Sphingolipids as Potential Indicators of Hepatic Necroinflammation in Patients with Chronic Hepatitis C and Normal Alanine Aminotransferase Level

    PubMed Central

    Ren, Jin-Yu; Wu, Hui-Li; Liu, Mei; Liu, Hui; Ren, Feng; Chen, Yu; Zhang, Jin-Lan; Duan, Zhong-Ping

    2014-01-01

    Accurate estimation of hepatic necroinflammation caused by chronic hepatitis C (CHC) is crucial for prediction of prognosis and design of therapeutic strategy, which is particularly true for CHC patients with normal alanine aminotransferase (ALT) level. Recent studies have shown that sphingolipids have a close relationship with hepatitis C virus infection. The present study aimed to identify plasma sphingolipids related to hepatic necroinflammation. We included 120 treatment-naïve CHC patients and 64/120 had normal ALT levels (<40 U/L). CHC patients who underwent liver biopsies were subjected to Scheuer scoring analysis for scope of hepatic inflammation. Plasma sphingolipids were detected by high-performance liquid chromatography tandem mass spectrometry. Our results showed 44 plasma sphingolipids were detected altogether. Of all detected sphingolipids, hexosylceramide (HexCer) (d18∶1/22∶0) and HexCer (d18∶1/24∶0) showed a significant difference among G0/G1, G2, and G3/G4 (P<0.05). For identifying hepatic necroinflammation (G≥2), after adjusting other factors, the odds ratio (OR) of HexCer (d18∶1/22∶0) reached 1.01 (95% confidence interval [CI]: 1.00–1.02). Furthermore, the area under the curve (AUC) of HexCer (d18∶1/22∶0) was 0.7 (P = 0.01) and approached that of ALT (AUC = 0.78). However, in CHC patients with normal ALT, HexCer (d18∶1/22∶0) was an independent factor (OR: 1.02, 95% CI: 1.01–1.03) to identify the hepatic necroinflammation (G≥2). HexCer (d18∶1/22∶0) not only showed the largest AUC (0.78, P = 0.001), but also exhibited the highest specificity of all indicators. These results indicate that plasma HexCer (d18∶1/22∶0) is a potential indicator to distinguish hepatic necroinflammation in CHC patients. For CHC with normal ALT, the ability of HexCer (d18∶1/22∶0) to distinguish hepatic necroinflammation might be superior to conventional serum indicators. PMID:24736528

  19. The association of liver fat content and serum alanine aminotransferase with bone mineral density in middle-aged and elderly Chinese men and postmenopausal women.

    PubMed

    Xia, Ming-Feng; Lin, Huan-Dong; Yan, Hong-Mei; Bian, Hua; Chang, Xin-Xia; Zhang, Lin-Shan; He, Wan-Yuan; Gao, Xin

    2016-01-13

    Recent studies have linked non-alcoholic fatty liver disease (NAFLD) to a reduced bone mineral density (BMD). We aimed to detect the quantitative association of liver fat content (LFC) and serum alanine aminotransferase (ALT) with BMD in a middle-aged and elderly Chinese population. The lumbar spine, hip and whole body BMDs were measured using dual-energy x-ray absorptiometry (Lunar iDXA, GE Healthcare) in 1659 Chinese (755 men and 1028 postmenopausal women) from Shanghai Changfeng community. Liver fat content was quantified via an ultrasound quantitative method. Multivariate linear regression analyses were carried out to determine the independent association of LFC and serum ALT with BMD and bone metabolic biomarkers. We also attempted to investigate the synergistic association between LFC and ALT as risk factors for bone mineral loss in Chinese. Subjects with higher LFC had significantly lower BMD at all skeletal sites. Univariate correlation analysis showed that both LFC and ALT were inversely associated with BMD at the spine (r = -0.116, P < 0.001 and r = -0.102, P = 0.005), hip (r = -0.095, P = 0.014 and r = -0.075, P = 0.041) and whole body sites (r = -0.134, P < 0.001 and r = -0.164, P < 0.001) in men. After confounders were controlled for, LFC and ALT remained associated with BMD and bone formation biomarkers in men, but not postmenopausal women. When both NAFLD and elevation of ALT were present, there was a significant synergistic worsening of the BMDs at all bone sites. Liver fat content and serum ALT were inversely correlated with BMD in middle-aged and elderly men. The underlying mechanism might relate to a reduction in osteoblast activity. Elevation of the hepatotoxic biomarker ALT may indicate high risk for osteoporosis in patients with NAFLD.

  20. Alanine aminotransferase elevation in obese infants and children: a marker of early onset non alcoholic Fatty liver disease.

    PubMed

    Engelmann, Guido; Hoffmann, Georg Friedrich; Grulich-Henn, Juergen; Teufel, Ulrike

    2014-04-01

    Elevated aminotransferases serve as surrogate markers of non-alcoholic fatty liver disease, a feature commonly associated with the metabolic syndrome. Studies on the prevalence of fatty liver disease in obese children comprise small patient samples or focus on those patients with liver enzyme elevation. We have prospectively analyzed liver enzymes in all overweight and obese children coming to our tertiary care centre. In a prospective study 224 healthy, overweight or obese children aged 1 - 12 years were examined. Body Mass Index-Standard Deviation Score, alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl-transpeptidase were measured. Elevated alanine aminotransferase was observed in 29% of children. 26 % of obese and 30 % of overweight children had liver enzyme elevations. Obese children had significantly higher alanine aminotransferase levels than overweight children (0.9 vs. 0.7 times the Upper Limit of Normal; P = 0.04). Elevation of liver enzymes appears in 29 % obese children in a tertiary care centre. Absolute alanine aminotransferase levels are significantly higher in obese than in overweight children. Even obese children with normal liver enzymes show signs of fatty liver disease as demonstrated by liver enzymes at the upper limit of normal.

  1. Alanine Aminotransferase Elevation in Obese Infants and Children: A Marker of Early Onset Non Alcoholic Fatty Liver Disease

    PubMed Central

    Engelmann, Guido; Hoffmann, Georg Friedrich; Grulich-Henn, Juergen; Teufel, Ulrike

    2014-01-01

    Background: Elevated aminotransferases serve as surrogate markers of non-alcoholic fatty liver disease, a feature commonly associated with the metabolic syndrome. Studies on the prevalence of fatty liver disease in obese children comprise small patient samples or focus on those patients with liver enzyme elevation. Objectives: We have prospectively analyzed liver enzymes in all overweight and obese children coming to our tertiary care centre. Patients and Methods: In a prospective study 224 healthy, overweight or obese children aged 1 - 12 years were examined. Body Mass Index-Standard Deviation Score, alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl-transpeptidase were measured. Results: Elevated alanine aminotransferase was observed in 29% of children. 26 % of obese and 30 % of overweight children had liver enzyme elevations. Obese children had significantly higher alanine aminotransferase levels than overweight children (0.9 vs. 0.7 times the Upper Limit of Normal; P = 0.04). Conclusions: Elevation of liver enzymes appears in 29 % obese children in a tertiary care centre. Absolute alanine aminotransferase levels are significantly higher in obese than in overweight children. Even obese children with normal liver enzymes show signs of fatty liver disease as demonstrated by liver enzymes at the upper limit of normal. PMID:24748893

  2. Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings.

    PubMed

    Kendziorek, Maria; Paszkowski, Andrzej; Zagdańska, Barbara

    2012-06-01

    Wheat (Triticum aestivum L.) seedlings contain four alanine aminotransferase (AlaAT) homologues. Two of them encode AlaAT enzymes, whereas two homologues act as glumate:glyoxylate aminotransferase (GGAT). To address the function of the distinct AlaAT homologues a comparative examination of the changes in transcript level together with the enzyme activity and alanine and glutamate content in wheat seedlings subjected to low oxygen availability, nitrogen and light deficiency has been studied. Shoots of wheat seedlings were more tolerant to hypoxia than the roots as judging on the basis of enzyme activity and transcript level. Hypoxia induced AlaAT1 earlier in roots than in shoots, while AlaAT2 and GGAT were unaffected. The increase in AlaAT activity lagged behind the increase in alanine content. Nitrogen deficiency has little effect on the activity of GGAT. In contrast, lower activity of AlaAT and the level of mRNA for AlaAT1 and AlaAT2 in wheat seedlings growing on a nitrogen-free medium seems to indicate that AlaAT is regulated by the availability of nitrogen. Both AlaAT and GGAT activities were present in etiolated wheat seedlings but their activity was half of that observed in light-grown seedlings. Exposure of etiolated seedlings to light caused an increase in enzyme activities and up-regulated GGAT1. It is proposed that hypoxia-induced AlaAT1 and light-induced peroxisomal GGAT1 appears to be crucial for the regulation of energy availability in plants grown under unfavourable environmental conditions. Key message In young wheat seedlings, both AlaAT and GGAT are down-regulated by nitrogen deficiency, whereas AlaAT1 is upregulated by hypoxia and GGAT1 by light.

  3. Inhibition of Alanine Aminotransferase in Silico and in Vivo Promotes Mitochondrial Metabolism to Impair Malignant Growth*

    PubMed Central

    Beuster, Gregor; Zarse, Kim; Kaleta, Christoph; Thierbach, René; Kiehntopf, Michael; Steinberg, Pablo; Schuster, Stefan; Ristow, Michael

    2011-01-01

    Cancer cells commonly exhibit increased nonoxidative d-glucose metabolism whereas induction of mitochondrial metabolism may impair malignant growth. We have first used an in silico method called elementary mode analysis to identify inhibition of ALAT (l-alanine aminotransferase) as a putative target to promote mitochondrial metabolism. We then experimentally show that two competitive inhibitors of ALAT, l-cycloserine and β-chloro-l-alanine, inhibit l-alanine production and impair d-glucose uptake of LLC1 Lewis lung carcinoma cells. The latter inhibition is linked to an initial energy deficit, as quantified by decreased ATP content, which is then followed by an activation of AMP-activated protein kinase and subsequently increased respiration rates and mitochondrial production of reactive oxygen species, culminating in ATP replenishment in ALAT-inhibited LLC1 cells. Moreover, we observe altered phosphorylation of p38 MAPK (mitogen-activated protein kinase 14), ERK (extracellular signal-regulated kinase 1/2), and Rb1 (retinoblastoma 1) proteins, as well as decreased expression of Cdc25a (cell decision cycle 25 homolog A) and Cdk4 (cyclin-dependent kinase 4). Importantly, these sequelae of ALAT inhibition culminate in similarly reduced anchorage-dependent and anchorage-independent growth rates of LLC1 cells, together suggesting that inhibition of ALAT efficiently impairs cancer growth by counteracting the Warburg effect due to compensatory activation of mitochondrial metabolism. PMID:21540181

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

    PubMed Central

    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

  5. Complex Association between Alanine Aminotransferase Activity and Mortality in General Population: A Systematic Review and Meta-Analysis of Prospective Studies

    PubMed Central

    Que, Shuping; Wang, Linlin; Qin, Xue

    2014-01-01

    Objective Controversy exists in using alanine aminotransferase (ALT) activity for predicting long-term survival. Therefore, this research study investigated the association between ALT activity and mortality through a systematic review and meta-analysis of previous prospective studies. Methods Electronic literature databases, including PubMed, Embase, and the Institute for Scientific Information (ISI), were searched for relevant prospective observational studies (published before Dec 30, 2013) on the association between baseline ALT activity and ensuing all-cause/disease-specific mortality. Information on nationality, sample size, participant characteristics, follow-up duration, comparison, outcome assessment, hazard ratios (HRs) and adjusted covariates was extracted. Pooled HRs and corresponding 95% confidence intervals (CIs) were separately calculated for categorical risk estimates (highest vs. lowest ALT categories) and continuous risk estimates (per 5 U/l of ALT increment) in subgroups separated by age (<70/≥70 years). Results A total of twelve prospective cohort studies, totaling 206,678 participants and 16,249 deaths, were identified and analyzed. In the younger age group, the pooled HR for mortality related to liver-disease was about 1.24 (95% CI: 1.23–1.25) per 5 U/l of ALT increment. The dose-response HRs of all-cause mortality, cardiovascular (CV) disease-related mortality, and cancer-related mortality were 0.91 (0.88–0.94), 0.91 (0.85–0.96), 0.92 (0.86–0.98) respectively per 5 U/l of ALT elevation, with insignificant heterogeneity in the older population. There was an approximate decrease of 4‰ observed on HRs of all-cause, CV-related, and cancer-related mortality followed with one year's increment through meta-regression (all P<0.05). Conclusions The ALT-mortality association was inconsistent and seems particularly susceptible to age after synthesizing the previous prospective studies. In terms of the age, ALT activity was more valuable in

  6. Complex association between alanine aminotransferase activity and mortality in general population: a systematic review and meta-analysis of prospective studies.

    PubMed

    Liu, Zhengtao; Ning, Huaijun; Que, Shuping; Wang, Linlin; Qin, Xue; Peng, Tao

    2014-01-01

    Controversy exists in using alanine aminotransferase (ALT) activity for predicting long-term survival. Therefore, this research study investigated the association between ALT activity and mortality through a systematic review and meta-analysis of previous prospective studies. Electronic literature databases, including PubMed, Embase, and the Institute for Scientific Information (ISI), were searched for relevant prospective observational studies (published before Dec 30, 2013) on the association between baseline ALT activity and ensuing all-cause/disease-specific mortality. Information on nationality, sample size, participant characteristics, follow-up duration, comparison, outcome assessment, hazard ratios (HRs) and adjusted covariates was extracted. Pooled HRs and corresponding 95% confidence intervals (CIs) were separately calculated for categorical risk estimates (highest vs. lowest ALT categories) and continuous risk estimates (per 5 U/l of ALT increment) in subgroups separated by age (<70/≥ 70 years). A total of twelve prospective cohort studies, totaling 206,678 participants and 16,249 deaths, were identified and analyzed. In the younger age group, the pooled HR for mortality related to liver-disease was about 1.24 (95% CI: 1.23-1.25) per 5 U/l of ALT increment. The dose-response HRs of all-cause mortality, cardiovascular (CV) disease-related mortality, and cancer-related mortality were 0.91 (0.88-0.94), 0.91 (0.85-0.96), 0.92 (0.86-0.98) respectively per 5 U/l of ALT elevation, with insignificant heterogeneity in the older population. There was an approximate decrease of 4‰ observed on HRs of all-cause, CV-related, and cancer-related mortality followed with one year's increment through meta-regression (all P<0.05). The ALT-mortality association was inconsistent and seems particularly susceptible to age after synthesizing the previous prospective studies. In terms of the age, ALT activity was more valuable in predicting mortality in the older population

  7. Determination of Alanine Aminotransferase with an Electrochemical Nano Ir-C Biosensor for the Screening of Liver Diseases

    PubMed Central

    Hsueh, Chang-Jung; Wang, Joanne H.; Dai, Liming; Liu, Chung-Chiun

    2011-01-01

    Alanine aminotransaminase (ALT), is an enzyme that normally resides in serum and body tissues, especially in the liver. It is released into the serum as a result of tissue injury; hence the concentration of ALT in the serum may be increased with acute damage to hepatic cells. A single use, disposable biosensor, comprising iridium nano-particle as catalyst dispersed on carbon paste, has been developed for the determination of ALT concentration. The biosensor is based on quantifying H2O2 concentration produced by a serial of ALT enzymatic reactions. It operates well at room temperature in different physiological fluids: phosphate buffer, calf serum and human serum for ALT concentration of 0–544 ng/mL. Experimental results in human serum are compared to those obtained by spectrophotometric assays with excellent agreement. Therefore, the Ir/C biosensor shows good relationship on the dilution of concentrated ALT clinical applications. PMID:25586923

  8. The Symptoms of Gastroesophageal Reflux Disease Correlate with High Body Mass Index, the Aspartate Aminotransferase/Alanine Aminotransferase Ratio and Insulin Resistance in Japanese Patients with Non-alcoholic Fatty Liver Disease.

    PubMed

    Fujiwara, Motoshi; Eguchi, Yuichiro; Fukumori, Norio; Eguchi, Hitoshi; Tomonaga, Motosuke; Yoshioka, Tsuneaki; Hyakutake, Masaki; Sakanishi, Yuta; Kyoraku, Itaru; Sugioka, Takashi; Fujimoto, Kazuma; Kusano, Motoyasu; Yamashita, Shu-ichi

    2015-01-01

    This study was designed to compare the association between the body mass index (BMI) and symptoms of gastroesophageal reflux disease (GERD) in allegedly normal subjects undergoing regular medical checkups and subjects diagnosed with non-alcoholic fatty liver disease (NAFLD). Additionally, the correlation between the BMI and GERD symptoms was evaluated in subjects with NAFLD. This study included 50 patients with NAFLD and 228 normal subjects evaluated during regular medical checkups. The height, weight, BMI, frequency scale for the symptoms of GERD (FSSG), and serum concentrations of triglycerides and γ-GTP were compared between the two groups. In the NAFLD group, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations were measured and insulin resistance was calculated using the quantitative insulin sensitivity check index (QUICKI). The total FSSG score moderately correlated with the BMI in the NAFLD group (r=0.342, p=0.015), but correlated negatively in the control group (r=-0.014, p=0.831). The FSSG score in the NAFLD group also negatively correlated with the AST/ALT ratio (r=-0.319) and insulin resistance calculated using the QUICKI score (r=-0.288). The BMI in the NAFLD group moderately correlated with the acid-reflux related score on the FSSG (r=0.389), and both the AST/ALT ratio (r=-0.344) and QUICKI score (r=-0.330) negatively correlated with the dyspepsia score on the FSSG. Obesity evaluated by the BMI was a significant risk factor for the exacerbation of GERD symptoms in subjects with NAFLD.

  9. Alanine and aspartate aminotransferase and glutamine-cycling pathway: their roles in pathogenesis of metabolic syndrome.

    PubMed

    Sookoian, Silvia; Pirola, Carlos J

    2012-08-07

    Although new research technologies are constantly used to look either for genes or biomarkers in the prediction of metabolic syndrome (MS), the pathogenesis and pathophysiology of this complex disease remains a major challenge. Interestingly, Cheng et al recently investigated possible pathways underlying MS by high-throughput metabolite profiling in two large and well characterized community-based cohorts. The authors explored by liquid chromatography and mass spectrometry the plasma concentrations of 45 distinct metabolites and examined their relation to cardiometabolic risk, and observed that metabolic risk factors such as obesity, insulin resistance (IR), high blood pressure, and dyslipidemia were associated with several metabolites, including branched-chain amino acids, other hydrophobic amino acids, tryptophan breakdown products, and nucleotide metabolites. In addition, the authors found a significant association of IR traits with glutamine, glutamate and the glutamine-to-glutamate ratio. These data provide new insight into the pathogenesis of MS-associated phenotypes and introduce a crucial role of glutamine-cycling pathway as prominently involved in the development of metabolic risk. We consider that the hypothesis about the role of abnormal glutamate metabolism in the pathogenesis of the MS is certainly challenging and suggests the critical role of the liver in the global metabolic modulation as glutamate metabolism is linked with aminotransferase reactions. We discuss here the critical role of the "liver metabolism" in the pathogenesis of the MS and IR, and postulate that before fatty liver develops, abnormal levels of liver enzymes, such as alanine and aspartate aminotransferases might reflect high levels of hepatic transamination of amino acids in the liver.

  10. 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.

  11. Folate Deficiency Was Associated with Increased Alanine Aminotransferase and Glutamyl Transpeptidase Concentrations in a Chinese Hypertensive Population: A Cross-Sectional Study.

    PubMed

    Li, Wen-Xing; Li, Wei; Cao, Jia-Qian; Yan, Haiyue; Sun, Yuanyuan; Zhang, Hong; Zhang, Qiang; Tang, Ling; Wang, Manman; Huang, Jing-Fei; Liu, Dahai

    2016-01-01

    Alanine aminotransferase (ALT), aspartate transaminase (AST), and glutamyl transpeptidase (GGT) were three key enzymes in the hepatic metabolism. This study aimed to investigate the effect of homocysteine (Hcy) metabolism gene polymorphisms and serum Hcy and folate level on the hepatic functions in a Chinese hypertensive population. A representative sample with 480 subjects aged 28-75 was enrolled in 2005.9-2005.12 from six hospitals in different Chinese regions. Serum ALT, AST and GGT were measured by using an automatic biochemistry analyzer. Serum Hcy was measured by high-performance liquid chromatography, and serum folate was measured by chemiluminescent immunoassay. Known genotypes were detected by PCR-RFLP methods. The results showed that the MTHFR C677T mutation was related a decreased serum AST level (r=-0.11, p=0.026), whereas the MTHFR A1298C mutation elevated serum AST level (r=0.11, p=0.032). Furthermore, multiple regression analysis showed that folate deficiency was associated with higher serum ALT (β (SE): 0.13 (0.06), p=0.031) and GGT level (β (SE): 0.18 (0.07), p=0.011). However, serum Hcy level may not affect the hepatic functions. Our data suggested that hepatic functions were affected by MTHFR gene polymorphisms and serum folate level. Further studies are needed to confirm these correlations in a larger population.

  12. Construction, purification and characterization of untagged human liver alanine-glyoxylate aminotransferase expressed in Escherichia coli.

    PubMed

    Cellini, Barbara; Montioli, Riccardo; Bianconi, Silvia; López-Alonso, Jorge P; Voltattorni, Carla Borri

    2008-01-01

    His-tagging is commonly used to aid and expedite the purification of recombinant proteins. It is commonly assumed, though less frequently tested, that the His-tag affects neither the structure nor the stability of the protein. Alanine:glyoxylate aminotransferase (AGT) is a peroxisomal pyridoxal 5'-phosphate (PLP) dependent enzyme which catalyzes the transamination of alanine and glyoxylate to pyruvate and glycine. AGT is a clinically relevant enzyme whose deficiency causes an inherited rare metabolic disorder named primary hyperoxaluria type I. Until now, the structure and function of this enzyme have been studied using recombinant wild-type AGT and variants purified using a hexa-histidine tag. However, the study of the functional roles of the N- and C-termini in the dimerization process and on the import into the peroxisome, respectively, requires the preparation of human liver AGT without histidine tags. We report for the first time the expression of untagged AGT together with a new rapid protocol for its purification. In addition, the kinetic parameters for the forward and reverse transamination catalyzed by untagged AGT as well as the spectroscopic features, the K(D(PLP)), the pH and thermal stability of the enzyme in the holo- and apo-form have been determined. This investigation will be the starting point for a detailed understanding of the contributions of the N- and C-termini on the dimerization and folding of AGT, and on its import into the peroxisome. This is prerequisite to understand how pathological mutations affect the proper native quaternary and tertiary structure, stability, and targeting of the enzyme.

  13. Structure of GroEL in Complex with an Early Folding Intermediate of Alanine Glyoxylate Aminotransferase*

    PubMed Central

    Albert, Armando; Yunta, Cristina; Arranz, Rocío; Peña, Álvaro; Salido, Eduardo; Valpuesta, José María; Martín-Benito, Jaime

    2010-01-01

    Primary hyperoxaluria type 1 is a rare autosomal recessive disease caused by mutations in the alanine glyoxylate aminotransferase gene (AGXT). We have previously shown that P11L and I340M polymorphisms together with I244T mutation (AGXT-LTM) represent a conformational disease that could be amenable to pharmacological intervention. Thus, the study of the folding mechanism of AGXT is crucial to understand the molecular basis of the disease. Here, we provide biochemical and structural data showing that AGXT-LTM is able to form non-native folding intermediates. The three-dimensional structure of a complex between the bacterial chaperonin GroEL and a folding intermediate of AGXT-LTM mutant has been solved by cryoelectron microscopy. The electron density map shows the protein substrate in a non-native extended conformation that crosses the GroEL central cavity. Addition of ATP to the complex induces conformational changes on the chaperonin and the internalization of the protein substrate into the folding cavity. The structure provides a three-dimensional picture of an in vivo early ATP-dependent step of the folding reaction cycle of the chaperonin and supports a GroEL functional model in which the chaperonin promotes folding of the AGXT-LTM mutant protein through forced unfolding mechanism. PMID:20056599

  14. Frequency of hepatitis C viral RNA in anti-hepatitis C virus non- reactive blood donors with raised alanine aminotransferase.

    PubMed

    Ali, Nadir; Ahmed, Syed Azhar; Moinuddin; Hoch, Susan Fisher; Chotani, Rashid A

    2011-12-01

    The objective of this study was to find out the frequency of HCV RNA in anti-HCV non-reactive blood donors with raised alanine amino transferase (ALT). The study was conducted at Baqai Institute of Haematology, Baqai Medical University, Karachi, in collaboration with Combined Military Hospital, Malir Cantt, Karachi. The demographic data of blood donors was recorded, and anti-HCV, HBsAg and HIV were screened. Four hundred consecutive donors with raised ALT above the reference range were included in study. HCV RNA RT-PCR was performed on 5 sample minipools using Bio-Rad Real time PCR equipment. HCV RNA was detected in 1/400 (0.25%) blood donors. Finding of raised ALT in blood donors warrants further investigations. In case, if raised ALT is unexplained presence of HCV RNA may be suspected.

  15. 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.

  16. Molecular Requirements for Peroxisomal Targeting of Alanine-Glyoxylate Aminotransferase as an Essential Determinant in Primary Hyperoxaluria Type 1

    PubMed Central

    Fodor, Krisztián; Wolf, Janina; Erdmann, Ralf; Schliebs, Wolfgang; Wilmanns, Matthias

    2012-01-01

    Alanine-glyoxylate aminotransferase is a peroxisomal enzyme, of which various missense mutations lead to irreversible kidney damage via primary hyperoxaluria type 1, in part caused by improper peroxisomal targeting. To unravel the molecular mechanism of its recognition by the peroxisomal receptor Pex5p, we have determined the crystal structure of the respective cargo–receptor complex. It shows an extensive protein/protein interface, with contributions from residues of the peroxisomal targeting signal 1 and additional loops of the C-terminal domain of the cargo. Sequence segments that are crucial for receptor recognition and hydrophobic core interactions within alanine-glyoxylate aminotransferase are overlapping, explaining why receptor recognition highly depends on a properly folded protein. We subsequently characterized several enzyme variants in vitro and in vivo and show that even minor protein fold perturbations are sufficient to impair Pex5p receptor recognition. We discuss how the knowledge of the molecular parameters for alanine-glyoxylate aminotransferase required for peroxisomal translocation could become useful for improved hyperoxaluria type 1 treatment. PMID:22529745

  17. 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

  18. Absolute quantification of serum microRNA-122 and its correlation with liver inflammation grade and serum alanine aminotransferase in chronic hepatitis C patients.

    PubMed

    Wang, Jiang-hua; Jiang, Dong; Rao, Hui-yng; Zhao, Jing-min; Wang, Yu; Wei, Lai

    2015-01-01

    MicroRNA-122 has been shown to be crucial for efficient HCV RNA replication in vitro. Pretreatment intrahepatic microRNA-122 levels in chronic hepatitis C (CHC) patients have been associated with the outcomes of interferon therapy. Here, we determined microRNA-122 serum levels in CHC patients and healthy donors using an absolute quantification approach and evaluated the correlation with liver inflammation grades and serum alanine aminotransferase (ALT) levels. Serum samples were collected from 105 treatment-naive CHC patients, 11 acute hepatitis patients, and 33 healthy donors. Serum microRNA-122 was measured using the TaqMan RT-qPCR. The cycle threshold values were converted to copy numbers by drawing a standard curve using a chemical synthetic standard. For accurate quantification, copy numbers were further normalized according to the recovery ratios of spiked-in cel-miR-39. Serum levels of microRNA-122 were significantly higher in acute hepatitis and CHC patients than in healthy donors (p<0.001). However, there was no significant association between microRNA-122 and ALT serum levels or liver inflammation grades. The present study showed that serum microRNA-122 was elevated in acute and chronic hepatitis patients. However, this biomarker for acute liver injury did not reflect the liver inflammation activity in CHC patients. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Modest weight loss and physical activity in overweight patients with chronic liver disease results in sustained improvements in alanine aminotransferase, fasting insulin, and quality of life.

    PubMed

    Hickman, I J; Jonsson, J R; Prins, J B; Ash, S; Purdie, D M; Clouston, A D; Powell, E E

    2004-03-01

    Obesity is a risk factor for progression of fibrosis in chronic liver diseases such as non-alcoholic fatty liver disease and hepatitis C. The aim of this study was to investigate the longer term effect of weight loss on liver biochemistry, serum insulin levels, and quality of life in overweight patients with liver disease and the effect of subsequent weight maintenance or regain. Thirty one patients completed a 15 month diet and exercise intervention. On completion of the intervention, 21 patients (68%) had achieved and maintained weight loss with a mean reduction of 9.4 (4.0)% body weight. Improvements in serum alanine aminotransferase (ALT) levels were correlated with the amount of weight loss (r = 0.35, p = 0.04). In patients who maintained weight loss, mean ALT levels at 15 months remained significantly lower than values at enrollment (p = 0.004), while in regainers (n = 10), mean ALT levels at 15 months were no different to values at enrollment (p = 0.79). Improvements in fasting serum insulin levels were also correlated with weight loss (r = 0.46, p = 0.04), and subsequent weight maintenance sustained this improvement. Quality of life was significantly improved after weight loss. Weight maintainers sustained recommended levels of physical activity and had higher fasting insulin levels (p = 0.03) at enrollment than weight regainers. In summary, these findings demonstrate that maintenance of weight loss and exercise in overweight patients with liver disease results in a sustained improvement in liver enzymes, serum insulin levels, and quality of life. Treatment of overweight patients should form an important component of the management of those with chronic liver disease.

  20. The aspartate aminotransferase-to-alanine aminotransferase ratio predicts all-cause and cardiovascular mortality in patients with type 2 diabetes

    PubMed Central

    Zoppini, Giacomo; Cacciatori, Vittorio; Negri, Carlo; Stoico, Vincenzo; Lippi, Giuseppe; Targher, Giovanni; Bonora, Enzo

    2016-01-01

    Abstract An increased aspartate aminotransferase-to-alanine aminotransferase ratio (AAR) has been widely used as a marker of advanced hepatic fibrosis. Increased AAR was also shown to be significantly associated with the risk of developing cardiovascular (CV) disease. The aim of this study was to assess the relationship between the AAR and mortality risk in a well-characterized cohort of patients with type 2 diabetes. A cohort of 2529 type 2 diabetic outpatients was followed-up for 6 years to collect cause-specific mortality. Cox regression analyses were modeled to estimate the independent association between AAR and the risk of all-cause and CV mortality. Over the 6-year follow-up period, 12.1% of patients died, 47.5% of whom from CV causes. An increased AAR, but not its individual components, was significantly associated with an increased risk of all-cause (adjusted-hazard risk 1.83, confidence interval [CI] 95% 1.14–2.93, P = 0.012) and CV (adjusted-hazard risk 2.60, CI 95% 1.38–4.90, P < 0.003) mortality after adjustment for multiple clinical risk factors and potential confounding variables. The AAR was independently associated with an increased risk of both all-cause and CV mortality in patients with type 2 diabetes. These findings suggest that an increased AAR may reflect more systemic derangements that are not simply limited to liver damage. Further studies are needed to elucidate the pathophysiological implications of an increased AAR. PMID:27787357

  1. The ribavirin analog ICN 17261 demonstrates reduced toxicity and antiviral effects with retention of both immunomodulatory activity and reduction of hepatitis-induced serum alanine aminotransferase levels.

    PubMed

    Tam, R C; Ramasamy, K; Bard, J; Pai, B; Lim, C; Averett, D R

    2000-05-01

    The demonstrated utility of the nucleoside analog ribavirin in the treatment of certain viral diseases can be ascribed to its multiple distinct properties. These properties may vary in relative importance in differing viral disease conditions and include the direct inhibition of viral replication, the promotion of T-cell-mediated immune responses via an enhanced type 1 cytokine response, and a reduction of circulating alanine aminotransferase (ALT) levels associated with hepatic injury. Ribavirin also has certain known toxicities, including the induction of anemia upon chronic administration. To determine if all these properties are linked, we compared the D-nucleoside ribavirin to its L-enantiomer (ICN 17261) with regard to these properties. Strong similarities were seen for these two compounds with respect to induction of type 1 cytokine bias in vitro, enhancement of type 1 cytokine responses in vivo, and the reduction of serum ALT levels in a murine hepatitis model. In contrast, ICN 17261 had no in vitro antiviral activity against a panel of RNA and DNA viruses, while ribavirin exhibited its characteristic activity profile. Importantly, the preliminary in vivo toxicology profile of ICN 17261 is significantly more favorable than that of ribavirin. Administration of 180 mg of ICN 17261 per kg of body weight to rats by oral gavage for 4 weeks generated substantial serum levels of drug but no observable clinical pathology, whereas equivalent doses of ribavirin induced a significant anemia and leukopenia. Thus, structural modification of ribavirin can dissociate its immunomodulatory properties from its antiviral and toxicologic properties, resulting in a compound (ICN 17261) with interesting therapeutic potential.

  2. Liver peroxisomal alanine:glyoxylate aminotransferase and the effects of mutations associated with Primary Hyperoxaluria Type I: An overview.

    PubMed

    Oppici, Elisa; Montioli, Riccardo; Cellini, Barbara

    2015-09-01

    Liver peroxisomal alanine:glyoxylate aminotransferase (AGT) (EC 2.6.1.44) catalyses the conversion of l-alanine and glyoxylate to pyruvate and glycine, a reaction that allows glyoxylate detoxification. Inherited mutations on the AGXT gene encoding AGT lead to Primary Hyperoxaluria Type I (PH1), a rare disorder characterized by the deposition of calcium oxalate crystals primarily in the urinary tract. Here we describe the results obtained on the biochemical features of AGT as well as on the molecular and cellular effects of polymorphic and pathogenic mutations. A complex scenario on the molecular pathogenesis of PH1 emerges in which the co-inheritance of polymorphic changes and the condition of homozygosis or compound heterozygosis are two important factors that determine the enzymatic phenotype of PH1 patients. All the reported data represent relevant steps toward the understanding of genotype/phenotype correlations, the prediction of the response of the patients to the available therapies, and the development of new therapeutic approaches. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.

  3. BarR, an Lrp-type transcription factor in Sulfolobus acidocaldarius, regulates an aminotransferase gene in a β-alanine responsive manner.

    PubMed

    Liu, Han; Orell, Alvaro; Maes, Dominique; van Wolferen, Marleen; Lindås, Ann-Christin; Bernander, Rolf; Albers, Sonja-Verena; Charlier, Daniel; Peeters, Eveline

    2014-05-01

    In archaea, nothing is known about the β-alanine degradation pathway or its regulation. In this work, we identify and characterize BarR, a novel Lrp-like transcription factor and the first one that has a non-proteinogenic amino acid ligand. BarR is conserved in Sulfolobus acidocaldarius and Sulfolobus tokodaii and is located in a divergent operon with a gene predicted to encode β-alanine aminotransferase. Deletion of barR resulted in a reduced exponential growth rate in the presence of β-alanine. Furthermore, qRT-PCR and promoter activity assays demonstrated that BarR activates the expression of the adjacent aminotransferase gene, but only upon β-alanine supplementation. In contrast, auto-activation proved to be β-alanine independent. Heterologously produced BarR is an octamer in solution and forms a single complex by interacting with multiple sites in the 170 bp long intergenic region separating the divergently transcribed genes. In vitro, DNA binding is specifically responsive to β-alanine and site-mutant analyses indicated that β-alanine directly interacts with the ligand-binding pocket. Altogether, this work contributes to the growing body of evidence that in archaea, Lrp-like transcription factors have physiological roles that go beyond the regulation of α-amino acid metabolism.

  4. Difference in serum complement component C4a levels between hepatitis C virus carriers with persistently normal alanine aminotransferase levels or chronic hepatitis C.

    PubMed

    Imakiire, Kazuyuki; Uto, Hirofumi; Sato, Yuko; Sasaki, Fumisato; Mawatari, Seiichi; Ido, Akio; Shimoda, Kazuya; Hayashi, Katsuhiro; Stuver, Sherri O; Ito, Yoshito; Okanoue, Takeshi; Tsubouchi, Hirohito

    2012-08-01

    Certain hepatitis C virus (HCV) carriers exhibit persistently normal alanine aminotransferase (ALT) levels (PNALT) (≤ 30 IU/l) accompanied by normal platelet counts (≥ 15 x 10(4)/µl); these individuals show milder disease activity and slower progression to cirrhosis. This study aimed to elucidate the characteristics of HCV carriers with PNALT using serum proteomics. The first group of subjects, who underwent clinical evaluation in the hospital, consisted of 19 HCV carriers with PNALT (PNALT-1) and 20 chronic hepatitis C (CHC-1) patients. The second group of subjects was part of a cohort study on the natural history of liver disease, and included 37 PNALT (PNALT-2) and 30 CHC (CHC-2) patients. Affinity bead-purified serum protein was subjected to matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis. Serum proteomics showed that 6 protein peaks with mass-to-charge ratios ranging from 1,000 to 3,000 differed significantly between the PNALT-1 and CHC-1 groups. Among these peaks, a 1738-m/z peak protein was identified as a fragment of complement component 4 (C4) and correlated significantly with serum C4a concentrations as determined by enzyme immunoassay. Serum C4a levels were also significantly higher in the PNALT-2 group compared to the CHC-2 group and healthy volunteers. Furthermore, in the PNALT-2 group, serum C4a levels negatively correlated with transaminase levels, but not with other biochemical tests, HCV core antigen levels, peripheral blood cell counts or serum hepatic fibrosis markers. This study indicates that host factors such as C4a not only differ between HCV carriers with PNALT and CHC, but that proteomic approaches could also contribute to the elucidation of factors in PNALT as more differences are discovered.

  5. The association between the genetic polymorphism of HLA-DQA1, DQB1, and DRB1 and serum alanine aminotransferase levels in chronic hepatitis C in the Chinese population.

    PubMed

    Yu, Rong-Bin; Hong, Xin; Ding, Wei-Liang; Tan, Yong-Fei; Zhang, Yong-Xiang; Sun, Nan-Xiong; Wu, Guan-Ling; Zhan, Sheng-Wei; Ge, Da-Fang

    2008-09-01

    To investigate a possible association between HLA genes with serum alanine aminotransferase (ALT) levels and evaluate whether the HLA-DQA1, DQB1, and DRB1 genes could influence the development of liver damage in chronic hepatitis C. A total of 145 patients with chronic hepatitis C virus (HCV) infection (36 patients with persistently normal ALT values; 109 patients with elevated ALT levels) and 160 uninfected healthy controls were examined for HLA-DQA1, DQB1, and DRB1 molecules by using polymerase chain reaction-sequencing based typing (PCR-SBT). Among the patients chronically infected with HCV, the frequencies of DQA1*0501, DQB1*0301, and DRB1*0401 alleles were significantly increased in the normal ALT group compared with those with abnormal ALT levels, whereas that of DQB1*0201 was significantly lower. As compared to uninfected healthy controls, DQA1*0501, DQB1*0301, and DRB1*0401 allele frequencies were also statistically higher in the normal ALT group, whereas that of DQB1*0201 was the inverse. The haplotype frequencies of DQA1*0301-DQB1*0301, DQA1*0501-DQB1*0301, and DRB1*1101-DQB1*0301 were found to be significantly higher in the normal ALT group. Multivariate logistic regression indicated that female sex, and the DQB1*0301 allele and DRB1*0401 allele were independently associated with normal ALT values, whereas DQB1*0201 allele was the inverse. These results suggest that particular HLA alleles may have an influence on the serum ALT level of chronic HCV infection as a host genetic factor in the Chinese population. The DQA1*0501, DQB1*0301, and DRB1*0401 alleles, and the DQA1*0301-DQB1*0301, DQA1*0501-DQB1*0301, and DRB1*1101-DQB1*0301 haplotypes seem to be associated with low hepatitis activity; whereas DQB1*0201 allele is closely correlated with the progression of liver injury in chronic HCV infection.

  6. Peroxisomal Alanine: Glyoxylate Aminotransferase AGT1 Is Indispensable for Appressorium Function of the Rice Blast Pathogen, Magnaporthe oryzae

    PubMed Central

    Bhadauria, Vijai; Banniza, Sabine; Vandenberg, Albert; Selvaraj, Gopalan; Wei, Yangdou

    2012-01-01

    The role of β-oxidation and the glyoxylate cycle in fungal pathogenesis is well documented. However, an ambiguity still remains over their interaction in peroxisomes to facilitate fungal pathogenicity and virulence. In this report, we characterize a gene encoding an alanine, glyoxylate aminotransferase 1 (AGT1) in Magnaporthe oryzae, the causative agent of rice blast disease, and demonstrate that AGT1 is required for pathogenicity of M. oryzae. Targeted deletion of AGT1 resulted in the failure of penetration via appressoria; therefore, mutants lacking the gene were unable to induce blast symptoms on the hosts rice and barley. This penetration failure may be associated with a disruption in lipid mobilization during conidial germination as turgor generation in the appressorium requires mobilization of lipid reserves from the conidium. Analysis of enhanced green fluorescent protein expression using the transcriptional and translational fusion with the AGT1 promoter and open reading frame, respectively, revealed that AGT1 expressed constitutively in all in vitro grown cell types and during in planta colonization, and localized in peroxisomes. Peroxisomal localization was further confirmed by colocalization with red fluorescent protein fused with the peroxisomal targeting signal 1. Surprisingly, conidia produced by the Δagt1 mutant were unable to form appressoria on artificial inductive surfaces, even after prolonged incubation. When supplemented with nicotinamide adenine dinucleotide (NAD+)+pyruvate, appressorium formation was restored on an artificial inductive surface. Taken together, our data indicate that AGT1-dependent pyruvate formation by transferring an amino group of alanine to glyoxylate, an intermediate of the glyoxylate cycle is required for lipid mobilization and utilization. This pyruvate can be converted to non-fermentable carbon sources, which may require reoxidation of NADH generated by the β-oxidation of fatty acids to NAD+ in peroxisomes

  7. Predictors of treatment requirement in HBeAg-negative chronic hepatitis B patients with persistently normal alanine aminotransferase and high serum HBV DNA levels.

    PubMed

    Ormeci, Aslı; Aydın, Yucel; Sumnu, Abdullah; Baran, Bulent; Soyer, Ozlem Mutluay; Pınarbasi, Binnur; Gokturk, Suut; Gulluoglu, Mine; Onel, Derya; Badur, Selim; Akyuz, Filiz; Karaca, Cetin; Demir, Kadir; Besisik, Fatih; Kaymakoglu, Sabahattin

    2016-11-01

    Serum alanine aminotransferase (ALT) is a controversial marker for disease monitoring in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients. The aim of this study was to determine the fibrosis stage and histological activity index (HAI) in HBeAg-negative CHB patients with persistently normal ALT (PNALT) and high serum HBV DNA (≥2000 IU/ml) and to investigate clinical risk factors for the requirement of treatment through the examination of liver biopsy specimens. HBeAg-negative CHB patients with PNALT (≤40 IU/l) and high serum HBV DNA (≥2000 IU/ml) were included. HBV fibrosis stage and HAI were scored according to the Ishak system. Multivariate logistic regression analysis was used to estimate the independent risk factors for fibrosis stage ≥2 and/or HAI ≥6. Receiver operating characteristic curve analysis was used to determine an optimal age cut-off for liver biopsy. A total 120 patients were enrolled. These patients had a mean HBV DNA level of 123680±494500 IU/ml; the HBV DNA load was 2000-20000 IU/ml in 68 patients (56.6%) and ≥20000 IU/ml in 52 (43.4%). Eighteen patients (15%) had moderate-to-severe histological activity (HAI ≥6). Forty-three patients (35.9%) had a fibrosis stage ≥2. Forty-eight patients (40%) had a fibrosis stage ≥2 and/or HAI ≥6. On multivariate logistic regression analysis, independent variables associated with fibrosis stage ≥2 and/or HAI ≥6 included age and HBV DNA viral load. Patients with HBV DNA 2000-20000 IU/ml were more likely to require treatment compared to those with a viral load ≥20000 IU/ml. The optimal age cut-off to predict fibrosis stage ≥2 and/or HAI ≥6 was 46 years. Significant liver damage was detected in 40% of CHB patients with PNALT and high HBV DNA upon biopsy. Age and HBV DNA viral load were independent predictors of significant liver damage. A biopsy to determine the degree of liver damage is advisable for CHB patients older than 46 years. Copyright © 2016 The

  8. A Novel Pathway for Metabolism of the Cardiovascular Risk Factor Homoarginine by alanine:glyoxylate aminotransferase 2

    PubMed Central

    Rodionov, Roman N.; Oppici, Elisa; Martens-Lobenhoffer, Jens; Jarzebska, Natalia; Brilloff, Silke; Burdin, Dmitrii; Demyanov, Anton; Kolouschek, Anne; Leiper, James; Maas, Renke; Cellini, Barbara; Weiss, Norbert; Bode-Böger, Stefanie M.

    2016-01-01

    Low plasma concentrations of L-homoarginine are associated with an increased risk of cardiovascular events, while homoarginine supplementation is protective in animal models of metabolic syndrome and stroke. Catabolism of homoarginine is still poorly understood. Based on the recent findings from a Genome Wide Association Study we hypothesized that homoarginine can be metabolized by alanine:glyoxylate aminotransferase 2 (AGXT2). We purified human AGXT2 from tissues of AGXT2 transgenic mice and demonstrated its ability to metabolize homoarginine to 6-guanidino-2-oxocaproic acid (GOCA). After incubation of HepG2 cells overexpressing AGXT2 with isotope-labeled homoarginine-d4 we were able to detect labeled GOCA in the medium. We injected wild type mice with labeled homoarginine and detected labeled GOCA in the plasma. We found that AGXT2 knockout (KO) mice have higher homoarginine and lower GOCA plasma levels as compared to wild type mice, while the reverse was true for AGXT2 transgenic (Tg) mice. In summary, we experimentally proved the presence of a new pathway of homoarginine catabolism – its transamination by AGXT2 with formation of GOCA and demonstrated that endogenous AGXT2 is required for maintenance of homoarginine levels in mice. Our findings may lead to development of novel therapeutic approaches for cardiovascular pathologies associated with homoarginine deficiency. PMID:27752063

  9. 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.

  10. Natural and Unnatural Compounds Rescue Folding Defects of Human Alanine: Glyoxylate Aminotransferase Leading to Primary Hyperoxaluria Type I.

    PubMed

    Oppici, Elisa; Montioli, Riccardo; Dindo, Mirco; Cellini, Barbara

    2016-01-01

    The functional deficit of alanine:glyoxylate aminotransferase (AGT) in human hepatocytes leads to a rare recessive disorder named primary hyperoxaluria type I (PH1). PH1 is characterized by the progressive accumulation and deposition of calcium oxalate stones in the kidneys and urinary tract, leading to a life-threatening and potentially fatal condition. In the last decades, substantial progress in the clarification of the molecular pathogenesis of the disease have been made. They resulted in the understanding that many mutations cause AGT deficiency by affecting the folding pathway of the protein leading to a reduced expression level, an increased aggregation propensity, and/or an aberrant mitochondrial localization. Thus, PH1 can be considered a misfolding disease and possibly treated by approaches aimed at counteracting the conformational defects of the variants. In this review, we summarize recent advances in the development of new strategies to identify molecules able to rescue AGT folding and trafficking either by acting as pharmacological chaperones or by preventing the mistargeting of the protein.

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

    PubMed Central

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

    2016-01-01

    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 0.3 μM 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

  12. Genetic variations in the alanine-glyoxylate aminotransferase 2 (AGXT2) gene and dimethylarginines levels in rheumatoid arthritis.

    PubMed

    Dimitroulas, Theodoros; Hodson, James; Panoulas, Vasileios F; Sandoo, Aamer; Smith, Jacqueline; Kitas, George

    2017-03-29

    Rheumatoid arthritis (RA) is associated with high rates of cardiovascular events mainly due to coronary and cerebrovascular atherosclerotic disease. Asymmetric (ADMA) and symmetric (SDMA) dimethylarginines are endogenous inhibitors of nitric oxide synthase and have been repeatedly linked with adverse cardiovascular outcomes in the general population and various disease settings. Alanine-glyoxylate aminotransferase 2 (AGTX2) is considered an alternative metabolic pathway contributing to the clearance of dimethylarginines in humans. The aim of the current study was to investigate the effect of specific AGXT-2 gene polymorphisms on circulating levels of ADMA or SDMA in patients with RA. Serum ADMA and SDMA levels were measured in 201 individuals with RA [median age: 67 years (IQR: 59-73), 155 females]. Two single nucleotide polymorphisms (SNPs) in the AGXT-2 gene-rs37369 and rs28305-were genotyped. Distributions of SDMA and ADMA were skewed, hence comparisons across the gene polymorphisms were performed using Kruskal-Wallis tests, and summarized using medians and interquartile ranges. Univariable analysis did not demonstrate a significant difference in the levels of SDMA or ADMA amongst the different genotypic groups of either rs37369AGXT2 (p = 0.800, 0.977) or rs28305AGXT2 (p = 0.463, 0.634). In multivariable analyses, ADMA levels were found to be significantly associated with erythrocyte sedimentation rate and estimated glomerular filtration rate, whilst SDMA levels were significantly associated with estimated glomerular filtration rate and quantitative insulin sensitivity check index. After adjustments for these factors, the relationship between the AGXT2 gene variants and both ADMA and SDMA remained non-significant. Our study in a well-characterized RA population did not show an association between serum concentrations of dimethylarginines and genetic variants of the AGXT2 gene.

  13. Identification of mutations associated with peroxisome-to-mitochondrion mistargeting of alanine/glyoxylate aminotransferase in primary hyperoxaluria type 1

    PubMed Central

    1990-01-01

    We have previously shown that in some patients with primary hyperoxaluria type 1 (PH1), disease is associated with mistargeting of the normally peroxisomal enzyme alanine/glyoxylate aminotransferase (AGT) to mitochondria (Danpure, C.J., P.J. Cooper, P.J. Wise, and P.R. Jennings. J. Cell Biol. 108:1345-1352). We have synthesized, amplified, cloned, and sequenced AGT cDNA from a PH1 patient with mitochondrial AGT (mAGT). This identified three point mutations that cause amino acid substitutions in the predicted AGT protein sequence. Using PCR and allele-specific oligonucleotide hybridization, a range of PH1 patients and controls were screened for these mutations. This revealed that all eight PH1 patients with mAGT carried at least one allele with the same three mutations. Two were homozygous for this allele and six were heterozygous. In at least three of the heterozygotes, it appeared that only the mutant allele was expressed. All three mutations were absent from PH1 patients lacking mAGT. One mutation encoding a Gly----Arg substitution at residue 170 was not found in any of the control individuals. However, the other two mutations, encoding Pro----Leu and Ile----Met substitutions at residues 11 and 340, respectively, cosegregated in the normal population at an allelic frequency of 5-10%. In an individual homozygous for this allele (substitutions at residues 11 and 340) only a small proportion of AGT appeared to be rerouted to mitochondria. It is suggested that the substitution at residue 11 generates an amphiphilic alpha-helix with characteristics similar to recognized mitochondrial targeting sequences, the full functional expression of which is dependent upon coexpression of the substitution at residue 170, which may induce defective peroxisomal import. PMID:1703535

  14. Diet and the frequency of the alanine:glyoxylate aminotransferase Pro11Leu polymorphism in different human populations.

    PubMed

    Caldwell, Elizabeth F; Mayor, Lianne R; Thomas, Mark G; Danpure, Christopher J

    2004-11-01

    The intermediary metabolic enzyme alanine:glyoxylate aminotransferase (AGT) contains a Pro11Leu polymorphism that decreases its catalytic activity by a factor of three and causes a small proportion to be mistargeted from its normal intracellular location in the peroxisomes to the mitochondria. These changes are predicted to have significant effects on the synthesis and excretion of the metabolic end-product oxalate and the deposition of insoluble calcium oxalate in the kidney and urinary tract. Based on the evolution of AGT targeting in mammals, we have previously hypothesised that this polymorphism would be advantageous for individuals who have a meat-rich diet, but disadvantageous for those who do not. If true, the frequency distribution of Pro11Leu in different extant human populations should have been shaped by their dietary history so that it should be more common in populations with predominantly meat-eating ancestral diets than it is in populations in which the ancestral diets were predominantly vegetarian. In the present study, we have determined frequency of Pro11Leu in 11 different human populations with divergent ancestral dietary lifestyles. We show that the Pro11Leu allelic frequency varies widely from 27.9% in the Saami, a population with a very meat-rich ancestral diet, to 2.3% in Chinese, who are likely to have had a more mixed ancestral diet. FST analysis shows that the differences in Pro11Leu frequency between some populations (particularly Saami vs Chinese) was very high when compared with neutral loci, suggesting that its frequency might have been shaped by dietary selection pressure.

  15. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Molecular defects of the glycine 41 variants of alanine glyoxylate aminotransferase associated with primary hyperoxaluria type I

    PubMed Central

    Cellini, Barbara; Montioli, Riccardo; Paiardini, Alessandro; Lorenzetto, Antonio; Maset, Fabio; Bellini, Tiziana; Oppici, Elisa; Voltattorni, Carla Borri

    2010-01-01

    G41 is an interfacial residue located within the α-helix 34–42 of alanine:glyoxylate aminotransferase (AGT). Its mutations on the major (AGT-Ma) or the minor (AGT-Mi) allele give rise to the variants G41R-Ma, G41R-Mi, and G41V-Ma causing hyperoxaluria type 1. Impairment of dimerization in these variants has been suggested to be responsible for immunoreactivity deficiency, intraperoxisomal aggregation, and sensitivity to proteasomal degradation. However, no experimental evidence supports this view. Here we report that G41 mutations, besides increasing the dimer-monomer equilibrium dissociation constant, affect the protein conformation and stability, and perturb its active site. As compared to AGT-Ma or AGT-Mi, G41 variants display different near-UV CD and intrinsic emission fluorescence spectra, larger exposure of hydrophobic surfaces, sensitivity to Met53-Tyr54 peptide bond cleavage by proteinase K, decreased thermostability, reduced coenzyme binding affinity, and catalytic efficiency. Additionally, unlike AGT-Ma and AGT-Mi, G41 variants under physiological conditions form insoluble inactive high-order aggregates (∼5,000 nm) through intermolecular electrostatic interactions. A comparative molecular dynamics study of the putative structures of AGT-Mi and G41R-Mi predicts that G41 → R mutation causes a partial unwinding of the 34–42 α-helix and a displacement of the first 44 N-terminal residues including the active site loop 24–32. These simulations help us to envisage the possible structural basis of AGT dysfunction associated with G41 mutations. The detailed insight into how G41 mutations act on the structure-function of AGT may contribute to achieve the ultimate goal of correcting the effects of these mutations. PMID:20133649

  17. Molecular defects of the glycine 41 variants of alanine glyoxylate aminotransferase associated with primary hyperoxaluria type I.

    PubMed

    Cellini, Barbara; Montioli, Riccardo; Paiardini, Alessandro; Lorenzetto, Antonio; Maset, Fabio; Bellini, Tiziana; Oppici, Elisa; Voltattorni, Carla Borri

    2010-02-16

    G41 is an interfacial residue located within the alpha-helix 34-42 of alanine:glyoxylate aminotransferase (AGT). Its mutations on the major (AGT-Ma) or the minor (AGT-Mi) allele give rise to the variants G41R-Ma, G41R-Mi, and G41V-Ma causing hyperoxaluria type 1. Impairment of dimerization in these variants has been suggested to be responsible for immunoreactivity deficiency, intraperoxisomal aggregation, and sensitivity to proteasomal degradation. However, no experimental evidence supports this view. Here we report that G41 mutations, besides increasing the dimer-monomer equilibrium dissociation constant, affect the protein conformation and stability, and perturb its active site. As compared to AGT-Ma or AGT-Mi, G41 variants display different near-UV CD and intrinsic emission fluorescence spectra, larger exposure of hydrophobic surfaces, sensitivity to Met53-Tyr54 peptide bond cleavage by proteinase K, decreased thermostability, reduced coenzyme binding affinity, and catalytic efficiency. Additionally, unlike AGT-Ma and AGT-Mi, G41 variants under physiological conditions form insoluble inactive high-order aggregates (approximately 5,000 nm) through intermolecular electrostatic interactions. A comparative molecular dynamics study of the putative structures of AGT-Mi and G41R-Mi predicts that G41 --> R mutation causes a partial unwinding of the 34-42 alpha-helix and a displacement of the first 44 N-terminal residues including the active site loop 24-32. These simulations help us to envisage the possible structural basis of AGT dysfunction associated with G41 mutations. The detailed insight into how G41 mutations act on the structure-function of AGT may contribute to achieve the ultimate goal of correcting the effects of these mutations.

  18. Glycolysis and the tricarboxylic acid cycle are linked by alanine aminotransferase during hypoxia induced by waterlogging of Lotus japonicus.

    PubMed

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

    2010-03-01

    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.

  19. Plasma aminotransferase concentrations in preterm infants.

    PubMed

    Victor, S; Dickinson, H; Turner, M A

    2011-03-01

    The aim of this study was to generate reference ranges for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in preterm infants by describing the observed plasma concentration of these enzymes in babies born between 22 and 36 weeks' gestation. A service evaluation was conducted in babies admitted to two large neonatal intensive care units in the UK. 7006 blood samples from 1860 infants admitted to the two units between 2004 and 2008 were included. Extremely premature infants had high plasma enzyme activities when compared to babies at a later corrected gestational age. This may be due to more severe illness immediately after birth.

  20. delta-Aminolevulinic acid formation. Purification and properties of alanine:4,5-dioxovalerate, aminotransferase and isolation of 4,5-dioxovalerate from Clostridium tetanomorphum.

    PubMed

    Bajkowski, A S; Friedmann, H C

    1982-03-10

    L-Alanine:4,5-dioxovalerate aminotransferase, the enzyme that catalyzes the transamination between alanine and 4,5-dioxovalerate to yield delta-aminolevulinate and pyruvate, has been purified from extracts Clostridium tetanomorphum by acetone precipitation and successive tetanomorphum by acetone precipitation and successive chromatography on Sephadex G-150, hydroxyapatite, Octyl-Sepharose, and SP-Sephadex C-50. The enzyme is pure by the criterion of disc gel electrophoresis with varying polyacrylamide concentrations. It is dimeric, and has an apparent molecular weight of 111,000. Each molecule contains 2 molecules of pyridoxal 5-phosphate. The apparent Km values for 4,5-dioxovalerate and L-alanine are 0.26 and 1.96 mM, respectively. In addition to alanine, glutamate also is an effective amino group donor. The enzyme is inhibited by various keto acids as well as by inhibitors of pyridoxal phosphate-containing enzymes. It was possible to show that 4,5-dioxovalerate is formed by cultures of C. tetanomorphum when grown in the presence of 0.2 M levulinate, an inhibitor of 5-aminolevulinate dehydratase.

  1. Analysis of alanine aminotransferase in various organs of soybean (Glycine max) and in dependence of different nitrogen fertilisers during hypoxic stress.

    PubMed

    Rocha, Marcio; Sodek, Ladaslav; Licausi, Francesco; Hameed, Muhammad Waqar; Dornelas, Marcelo Carnier; van Dongen, Joost T

    2010-10-01

    Alanine aminotransferase (AlaAT) catalyses the reversible conversion of pyruvate and glutamate into alanine and oxoglutarate. In soybean, two subclasses were identified, each represented by two highly similar members. To investigate the role of AlaAT during hypoxic stress in soybean, changes in transcript level of both subclasses were analysed together with the enzyme activity and alanine content of the tissue. Moreover, the dependency of AlaAT activity and gene expression was investigated in relation to the source of nitrogen supplied to the plants. Using semi-quantitative PCR, GmAlaAT genes were determined to be highest expressed in roots and nodules. Under normal growth conditions, enzyme activity of AlaAT was detected in all organs tested, with lowest activity in the roots. Upon waterlogging-induced hypoxia, AlaAT activity increased strongly. Concomitantly, alanine accumulated. During re-oxygenation, AlaAT activity remained high, but the transcript level and the alanine content decreased. Our results show a role for AlaAT in the catabolism of alanine during the initial period of re-oxygenation following hypoxia. GmAlaAT also responded to nitrogen availability in the solution during waterlogging. Ammonium as nitrogen source induced both gene expression and enzyme activity of AlaAT more than when nitrate was supplied in the nutrient solution. The work presented here indicates that AlaAT might not only be important during hypoxia, but also during the recovery phase after waterlogging, when oxygen is available to the tissue again.

  2. Analysis of alanine aminotransferase in various organs of soybean (Glycine max) and in dependence of different nitrogen fertilisers during hypoxic stress

    PubMed Central

    Rocha, Marcio; Sodek, Ladaslav; Licausi, Francesco; Hameed, Muhammad Waqar; Dornelas, Marcelo Carnier

    2010-01-01

    Alanine aminotransferase (AlaAT) catalyses the reversible conversion of pyruvate and glutamate into alanine and oxoglutarate. In soybean, two subclasses were identified, each represented by two highly similar members. To investigate the role of AlaAT during hypoxic stress in soybean, changes in transcript level of both subclasses were analysed together with the enzyme activity and alanine content of the tissue. Moreover, the dependency of AlaAT activity and gene expression was investigated in relation to the source of nitrogen supplied to the plants. Using semi-quantitative PCR, GmAlaAT genes were determined to be highest expressed in roots and nodules. Under normal growth conditions, enzyme activity of AlaAT was detected in all organs tested, with lowest activity in the roots. Upon waterlogging-induced hypoxia, AlaAT activity increased strongly. Concomitantly, alanine accumulated. During re-oxygenation, AlaAT activity remained high, but the transcript level and the alanine content decreased. Our results show a role for AlaAT in the catabolism of alanine during the initial period of re-oxygenation following hypoxia. GmAlaAT also responded to nitrogen availability in the solution during waterlogging. Ammonium as nitrogen source induced both gene expression and enzyme activity of AlaAT more than when nitrate was supplied in the nutrient solution. The work presented here indicates that AlaAT might not only be important during hypoxia, but also during the recovery phase after waterlogging, when oxygen is available to the tissue again. PMID:20414691

  3. Non-alcoholic steatohepatitis with normal aminotransferase values.

    PubMed

    Uslusoy, Hüseyin Saadettin; Nak, Selim Giray; Gülten, Macit; Biyikli, Zeynep

    2009-04-21

    To investigate the aspects of liver histology in patients with non-alcoholic steatohepatitis (NASH) who had normal aminotransferase levels. Thirty-four patients diagnosed with liver steatosis by ultrasonographic examination participated in the study. We compared all non-alcoholic fatty liver disease and NASH cases, according to aminotransferase level, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio and presence of metabolic syndrome. Sixteen of 25 patients with high aminotransferase levels were diagnosed with NASH and nine with simple fatty liver according to liver histology. Among the nine patients with normal aminotransferase levels, seven had NASH and two had simple fatty liver. The patients with normal and high liver enzyme levels had almost the same prevalence of NASH and metabolic syndrome. Liver histology did not reveal any difference according to aminotransferase levels and AST/ALT ratio. Aminotransferase levels and AST/ALT ratio do not seem to be reliable predictors for NASH. Despite numerous non-invasive biomarkers, all patients with fatty liver should undergo liver biopsy.

  4. Non-alcoholic steatohepatitis with normal aminotransferase values

    PubMed Central

    Uslusoy, Hüseyin Saadettin; Nak, Selim Giray; Gülten, Macit; Bıyıklı, Zeynep

    2009-01-01

    AIM: To investigate the aspects of liver histology in patients with non-alcoholic steatohepatitis (NASH) who had normal aminotransferase levels. METHODS: Thirty-four patients diagnosed with liver steatosis by ultrasonographic examination participated in the study. We compared all non-alcoholic fatty liver disease and NASH cases, according to aminotransferase level, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio and presence of metabolic syndrome. RESULTS: Sixteen of 25 patients with high aminotransferase levels were diagnosed with NASH and nine with simple fatty liver according to liver histology. Among the nine patients with normal aminotransferase levels, seven had NASH and two had simple fatty liver. The patients with normal and high liver enzyme levels had almost the same prevalence of NASH and metabolic syndrome. Liver histology did not reveal any difference according to aminotransferase levels and AST/ALT ratio. CONCLUSION: Aminotransferase levels and AST/ALT ratio do not seem to be reliable predictors for NASH. Despite numerous non-invasive biomarkers, all patients with fatty liver should undergo liver biopsy. PMID:19370784

  5. Aminooxy acetic acid: a selective inhibitor of alanine:glyoxylate aminotransferase and its use in the diagnosis of primary hyperoxaluria type I.

    PubMed

    Andy, V; Horváth, P; Wanders, R J

    1995-12-29

    The diagnosis of primary hyperoxaluria type I is usually based on the determination of the activity of the hepatic peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). The activity observed, however, is due to the action of at least one more enzyme, i.e. glutamate:glyoxylate aminotransferase (GGT). Correction for the AGT activity displayed by GGT is usually made by use of a correction factor which correlates the activity of GGT with the amount of 'AGT' activity exhibited by GGT. This method, however, has a number of drawbacks: it corrects for only one other enzyme and it requires a second, rather insensitive and laborious enzyme assay to be performed which cannot be adapted to a centrifugal analyser. We therefore developed a simple and direct method for measurement of 'true' AGT activity which uses 100 mumol/l aminooxy acetic acid. Under these conditions AGT is completely inhibited and the contribution of GGT (and possibly other transaminases) to the L-alanine mediated transamination of glyoxylate can be measured directly. The 'true' AGT activities measured by this method correlated well with those measured in samples depleted of AGT by immunoprecipitation. Finally, this method proved to be fully compatible with the automated assay of AGT in a centrifugal analyser.

  6. A novel C-S lyase from the latex-producing plant Taraxacum brevicorniculatum displays alanine aminotransferase and l-cystine lyase activity.

    PubMed

    Munt, Oliver; Prüfer, Dirk; Schulze Gronover, Christian

    2013-01-01

    We isolated a novel pyridoxal-5-phosphate-dependent l-cystine lyase from the dandelion Taraxacum brevicorniculatum. Real time qPCR analysis showed that C-S lyase from Taraxacum brevicorniculatum (TbCSL) mRNA is expressed in all plant tissues, although at relatively low levels in the latex and pedicel. The 1251 bp TbCSL cDNA encodes a protein with a calculated molecular mass of 46,127 kDa. It is homologous to tyrosine and alanine aminotransferases (AlaATs) as well as to an Arabidopsis thaliana carbon-sulfur lyase (C-S lyase) (SUR1), which has a role in glucosinolate metabolism. TbCSL displayed in vitrol-cystine lyase and AlaAT activities of 4 and 19nkatmg(-1) protein, respectively. However, we detected no in vitro tyrosine aminotransferase (TyrAT) activity and RNAi knockdown of the enzyme had no effect on phenotype, showing that TbCSL substrates might be channeled into redundant pathways. TbCSL is in vivo localized in the cytosol and functions as a C-S lyase or an aminotransferase in planta, but the purified enzyme converts at least two substrates specifically, and can thus be utilized for further in vitro applications. Copyright © 2012 Elsevier GmbH. All rights reserved.

  7. 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.

  8. Frequency of hepatitis C viral RNA in anti-hepatitis C virus non- reactive blood donors with normal alanine aminotransferase.

    PubMed

    Ali, Nadir; Moinuddin; Ahmed, Syed Azhar; Chotani, Rashid A; Fisher-Hoch, Susan P

    2010-10-01

    To determine the frequency of HCV RNA in an anti-HCV non-reactive blood donor population with normal ALT, and its cost effectiveness. An observational study. Baqai Institute of Haematology, Baqai Medical University, Karachi, and Combined Military Hospital, Malir Cantt, Karachi, from May 2006 to April 2008. After initial interview and mini-medical examination, demographic data of blood donors was recorded, and anti-HCV, HBsAg and HIV were screened by third generation ELISA. Those reactive to anti-HCV, HbsAg and/or HIV were excluded. Four hundred consecutive donors with ALT within the reference range of 15-41 units/L were included in study. HCV RNA RT-PCR was performed on 5 sample mini-pools using Bio-Rad Real time PCR equipment. All 400 donors were male, with mean age 27 years SD + 6.2. ALT of blood donors varied between 15-41 U/L with mean of 31.5+6.4 U/L, HCV RNA was detected in 2/400 (0.5%) blood donors. Screening one blood bag for HCV RNA costs Rs 4,000.00 equivalent to 50 US dollars, while screening through 5 sample mini-pools was Rs. 800.00 equivalent to approximately 10 US dollars. HCV RNA frequency was 0.5% (2/400) in the studied anti-HCV non-reactive normal ALT blood donors. Screening through mini-pools is more cost-effective.

  9. CaAlaAT1 catalyzes the alanine: 2-oxoglutarate aminotransferase reaction during the resistance response against Tobacco mosaic virus in hot pepper.

    PubMed

    Kim, Ki-Jeong; Park, Chang-Jin; An, Jong-Min; Ham, Byung-Kook; Lee, Boo-Ja; Paek, Kyung-Hee

    2005-08-01

    Hot pepper (Capsicum annuum L. cv. Bugang) plants exhibit a hypersensitive response (HR) upon infection by Tobacco mosaic virus (TMV) pathotype P0. To elucidate molecular mechanism that underlies this resistance, hot pepper cv. Bugang leaves were inoculated with TMV-P0 and genes specifically up-regulated during the HR were isolated by differential screening. One of the clones, CaAlaAT1 encoding a putative alanine aminotransferase (EC 2.6.1.2) exhibited organ-specific expression pattern and the transcript accumulated abundantly in red (ripe) fruit tissues. CaAlaAT1 transcript was also induced in older leaves during senescence. The expression of CaAlaAT1 gene was increased in the incompatible interaction with TMV-P0 but was not in the compatible interaction with TMV-P1.2. When a strain of Xanthomonas campestris pv. vesicatoria (Xcv) carrying an AvrBs2 gene was infiltrated into the leaves of a pepper cv. ECW 20R carrying Bs2 resistance gene, a marked induction and maintenance of CaAlaAT1 gene expression was observed. The expression of CaAlaAT1 gene was triggered by salicylic acid (SA) and ethylene but not by methyl jasmonate (MeJA). CaAlaAT1 seemed to be localized mostly at the cytosol from the polyethylene glycol (PEG)-mediated transformation experiment. CaAlaAT1 seemed to catalyze alanine: 2-oxoglutarate aminotransferase (AKT) reaction, which was a main activity among the four activities in vitro, during the resistance response against TMV in hot pepper. These results suggest that CaAlaAT1, a protein known to be involved in metabolic reactions, might be one of the components in the plant's defense signal pathway against pathogens.

  10. Relationships Between Alanine Aminotransferase, Serum Triglycerides, Body Mass Index and Nonalcoholic Fatty Liver Disease in an Outpatient Pediatric Clinic Population.

    PubMed

    Cohen, Deborah; Gonzales-Pacheco, Diana; Myers, Orrin

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in children and adolescents. The goal of this study was to describe the demographic, anthropometric and biochemical data of children and adolescents diagnosed with NAFLD during a seven-year period in an outpatient pediatric clinic in the Southwest region of the US and to evaluate relationships between race, BMI, ALT, triglyceride levels, age and gender with a diagnosis of NAFLD. A retrospective medical record review of patients who attended an outpatient pediatric clinic with a billing diagnosis ICD-9 code of 571.8 was conducted. Forty-one patients met these criteria. The majority was male (74%) Hispanic (32%), Hispanic/Latino (68%) and obese. The small number of patients diagnosed with NAFLD in our study is consistent with previously reported results. Our results indicate that the population of this culturally diverse, high-risk population has significant clinical markers that are indicative of NAFLD. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Crystal structure of the S187F variant of human liver alanine: Aminotransferase associated with primary hyperoxaluria type I and its functional implications

    PubMed Central

    Oppici, Elisa; Fodor, Krisztian; Paiardini, Alessandro; Williams, Chris; Voltattorni, Carla Borri; Wilmanns, Matthias; Cellini, Barbara

    2013-01-01

    The substitution of Ser187, a residue located far from the active site of human liver peroxisomal alanine:glyoxylate aminotransferase (AGT), by Phe gives rise to a variant associated with primary hyperoxaluria type I. Unexpectedly, previous studies revealed that the recombinant form of S187F exhibits a remarkable loss of catalytic activity, an increased pyridoxal 5′-phosphate (PLP) binding affinity and a different coenzyme binding mode compared with normal AGT. To shed light on the structural elements responsible for these defects, we solved the crystal structure of the variant to a resolution of 2.9 Å. Although the overall conformation of the variant is similar to that of normal AGT, we noticed: (i) a displacement of the PLP-binding Lys209 and Val185, located on the re and si side of PLP, respectively, and (ii) slight conformational changes of other active site residues, in particular Trp108, the base stacking residue with the pyridine cofactor moiety. This active site perturbation results in a mispositioning of the AGT-pyridoxamine 5′-phosphate (PMP) complex and of the external aldimine, as predicted by molecular modeling studies. Taken together, both predicted and observed movements caused by the S187F mutation are consistent with the following functional properties of the variant: (i) a 300- to 500-fold decrease in both the rate constant of L-alanine half-transamination and the kcat of the overall transamination, (ii) a different PMP binding mode and affinity, and (iii) a different microenvironment of the external aldimine. Proposals for the treatment of patients bearing S187F mutation are discussed on the basis of these results. Proteins 2013; 81:1457–1465. © 2013 Wiley Periodicals, Inc. PMID:23589421

  12. Crystal structure of the S187F variant of human liver alanine: glyoxylate [corrected] aminotransferase associated with primary hyperoxaluria type I and its functional implications.

    PubMed

    Oppici, Elisa; Fodor, Krisztian; Paiardini, Alessandro; Williams, Chris; Voltattorni, Carla Borri; Wilmanns, Matthias; Cellini, Barbara

    2013-08-01

    The substitution of Ser187, a residue located far from the active site of human liver peroxisomal alanine:glyoxylate aminotransferase (AGT), by Phe gives rise to a variant associated with primary hyperoxaluria type I. Unexpectedly, previous studies revealed that the recombinant form of S187F exhibits a remarkable loss of catalytic activity, an increased pyridoxal 5'-phosphate (PLP) binding affinity and a different coenzyme binding mode compared with normal AGT. To shed light on the structural elements responsible for these defects, we solved the crystal structure of the variant to a resolution of 2.9 Å. Although the overall conformation of the variant is similar to that of normal AGT, we noticed: (i) a displacement of the PLP-binding Lys209 and Val185, located on the re and si side of PLP, respectively, and (ii) slight conformational changes of other active site residues, in particular Trp108, the base stacking residue with the pyridine cofactor moiety. This active site perturbation results in a mispositioning of the AGT-pyridoxamine 5'-phosphate (PMP) complex and of the external aldimine, as predicted by molecular modeling studies. Taken together, both predicted and observed movements caused by the S187F mutation are consistent with the following functional properties of the variant: (i) a 300- to 500-fold decrease in both the rate constant of L-alanine half-transamination and the kcat of the overall transamination, (ii) a different PMP binding mode and affinity, and (iii) a different microenvironment of the external aldimine. Proposals for the treatment of patients bearing S187F mutation are discussed on the basis of these results.

  13. The consensus-based approach for gene/enzyme replacement therapies and crystallization strategies: the case of human alanine-glyoxylate aminotransferase.

    PubMed

    Mesa-Torres, Noel; Yunta, Cristina; Fabelo-Rosa, Israel; Gonzalez-Rubio, Juana María; Sánchez-Ruiz, José M; Salido, Eduardo; Albert, Armando; Pey, Angel L

    2014-09-15

    Protein stability is a fundamental issue in biomedical and biotechnological applications of proteins. Among these applications, gene- and enzyme-replacement strategies are promising approaches to treat inherited diseases that may benefit from protein engineering techniques, even though these beneficial effects have been largely unexplored. In the present study we apply a sequence-alignment statistics procedure (consensus-based approach) to improve the activity and stability of the human AGT (alanine-glyoxylate aminotransferase) protein, an enzyme which causes PH1 (primary hyperoxaluria type I) upon mutation. By combining only five consensus mutations, we obtain a variant (AGT-RHEAM) with largely enhanced in vitro thermal and kinetic stability, increased activity, and with no side effects on foldability and peroxisomal targeting in mammalian cells. The structure of AGT-RHEAM reveals changes at the dimer interface and improved electrostatic interactions responsible for increased kinetic stability. Consensus-based variants maintained the overall protein fold, crystallized more easily and improved the expression as soluble proteins in two different systems [AGT and CIPK24 (CBL-interacting serine/threonine-protein kinase) SOS2 (salt-overly-sensitive 2)]. Thus the consensus-based approach also emerges as a simple and generic strategy to increase the crystallization success for hard-to-get protein targets as well as to enhance protein stability and function for biomedical applications.

  14. Gly161 mutations associated with Primary Hyperoxaluria Type I induce the cytosolic aggregation and the intracellular degradation of the apo-form of alanine:glyoxylate aminotransferase.

    PubMed

    Oppici, Elisa; Roncador, Alessandro; Montioli, Riccardo; Bianconi, Silvia; Cellini, Barbara

    2013-12-01

    Primary Hyperoxaluria Type I (PH1) is a severe rare disorder of metabolism due to inherited mutations on liver peroxisomal alanine:glyoxylate aminotransferase (AGT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme whose deficiency causes the deposition of calcium oxalate crystals in the kidneys and urinary tract. PH1 is an extremely heterogeneous disease and there are more than 150 disease-causing mutations currently known, most of which are missense mutations. Moreover, the molecular mechanisms by which missense mutations lead to AGT deficiency span from structural, functional to subcellular localization defects. Gly161 is a highly conserved residue whose mutation to Arg, Cys or Ser is associated with PH1. Here we investigated the molecular bases of the AGT deficit caused by Gly161 mutations with expression studies in a mammalian cellular system paired with biochemical analyses on the purified recombinant proteins. Our results show that the mutations of Gly161 (i) strongly reduce the expression levels and the intracellular half-life of AGT, and (ii) make the protein in the apo-form prone to an electrostatically-driven aggregation in the cell cytosol. The coenzyme PLP, by shifting the equilibrium from the apo- to the holo-form, is able to reduce the aggregation propensity of the variants, thus partly decreasing the effect of the mutations. Altogether, these results shed light on the mechanistic details underlying the pathogenicity of Gly161 variants, thus expanding our knowledge of the enzymatic phenotypes leading to AGT deficiency.

  15. Diabetes-linked transcription factor HNF4α regulates metabolism of endogenous methylarginines and β-aminoisobutyric acid by controlling expression of alanine-glyoxylate aminotransferase 2

    PubMed Central

    Burdin, Dmitry V.; Kolobov, Alexey A.; Brocker, Chad; Soshnev, Alexey A.; Samusik, Nikolay; Demyanov, Anton V.; Brilloff, Silke; Jarzebska, Natalia; Martens-Lobenhoffer, Jens; Mieth, Maren; Maas, Renke; Bornstein, Stefan R.; Bode-Böger, Stefanie M.; Gonzalez, Frank; Weiss, Norbert; Rodionov, Roman N.

    2016-01-01

    Elevated levels of circulating asymmetric and symmetric dimethylarginines (ADMA and SDMA) predict and potentially contribute to end organ damage in cardiovascular diseases. Alanine-glyoxylate aminotransferase 2 (AGXT2) regulates systemic levels of ADMA and SDMA, and also of beta-aminoisobutyric acid (BAIB)-a modulator of lipid metabolism. We identified a putative binding site for hepatic nuclear factor 4 α (HNF4α) in AGXT2 promoter sequence. In a luciferase reporter assay we found a 75% decrease in activity of Agxt2 core promoter after disruption of the HNF4α binding site. Direct binding of HNF4α to Agxt2 promoter was confirmed by chromatin immunoprecipitation assay. siRNA-mediated knockdown of Hnf4a led to an almost 50% reduction in Agxt2 mRNA levels in Hepa 1–6 cells. Liver-specific Hnf4a knockout mice exhibited a 90% decrease in liver Agxt2 expression and activity, and elevated plasma levels of ADMA, SDMA and BAIB, compared to wild-type littermates. Thus we identified HNF4α as a major regulator of Agxt2 expression. Considering a strong association between human HNF4A polymorphisms and increased risk of type 2 diabetes our current findings suggest that downregulation of AGXT2 and subsequent impairment in metabolism of dimethylarginines and BAIB caused by HNF4α deficiency might contribute to development of cardiovascular complications in diabetic patients. PMID:27752141

  16. Diabetes-linked transcription factor HNF4α regulates metabolism of endogenous methylarginines and β-aminoisobutyric acid by controlling expression of alanine-glyoxylate aminotransferase 2.

    PubMed

    Burdin, Dmitry V; Kolobov, Alexey A; Brocker, Chad; Soshnev, Alexey A; Samusik, Nikolay; Demyanov, Anton V; Brilloff, Silke; Jarzebska, Natalia; Martens-Lobenhoffer, Jens; Mieth, Maren; Maas, Renke; Bornstein, Stefan R; Bode-Böger, Stefanie M; Gonzalez, Frank; Weiss, Norbert; Rodionov, Roman N

    2016-10-18

    Elevated levels of circulating asymmetric and symmetric dimethylarginines (ADMA and SDMA) predict and potentially contribute to end organ damage in cardiovascular diseases. Alanine-glyoxylate aminotransferase 2 (AGXT2) regulates systemic levels of ADMA and SDMA, and also of beta-aminoisobutyric acid (BAIB)-a modulator of lipid metabolism. We identified a putative binding site for hepatic nuclear factor 4 α (HNF4α) in AGXT2 promoter sequence. In a luciferase reporter assay we found a 75% decrease in activity of Agxt2 core promoter after disruption of the HNF4α binding site. Direct binding of HNF4α to Agxt2 promoter was confirmed by chromatin immunoprecipitation assay. siRNA-mediated knockdown of Hnf4a led to an almost 50% reduction in Agxt2 mRNA levels in Hepa 1-6 cells. Liver-specific Hnf4a knockout mice exhibited a 90% decrease in liver Agxt2 expression and activity, and elevated plasma levels of ADMA, SDMA and BAIB, compared to wild-type littermates. Thus we identified HNF4α as a major regulator of Agxt2 expression. Considering a strong association between human HNF4A polymorphisms and increased risk of type 2 diabetes our current findings suggest that downregulation of AGXT2 and subsequent impairment in metabolism of dimethylarginines and BAIB caused by HNF4α deficiency might contribute to development of cardiovascular complications in diabetic patients.

  17. Alanine transaminase (ALT) blood test

    MedlinePlus

    ... liver damage. Normal Results The normal range is: Male: 10 to 40 U/L Female: 7 to 35 U/L Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your ...

  18. Statin-related aminotransferase elevation according to baseline aminotransferases level in real practice in Korea.

    PubMed

    Kim, H-S; Lee, S H; Kim, H; Lee, S-H; Cho, J H; Lee, H; Yim, H W; Kim, S-H; Choi, I-Y; Yoon, K-H; Kim, J H

    2016-06-01

    Higher rate of statin-related hepatotoxicity has been reported for Koreans than for Westerners. Moreover, statin-related aminotransferase elevation for those who show borderline levels of aspartate transaminase (AST) and alanine transaminase (ALT) (≤×3 of UNL) at baseline has not been fully investigated. Post-statin changes AST/ALT levels during the first year for 21 233 Korean outpatients at two large academic teaching hospitals from January 2009 to December 2013 were analysed using electronic health record data. The date of the first statin prescription was set as baseline. We also performed a comparative analysis of statin-related AST/ALT elevations according to the type of statin, followed by an analysis of clinical risk factors. The progression rate to abnormal AST/ALT values [>×3 the upper normal limit (UNL)] was significantly higher (2·4-16% vs. 0·3-1·7%, P < 0·001) in subjects with borderline (>×1, but ≤×3 of UNL) compared with normal AST/ALT values at baseline. Those with normal baseline AST/ALT did not show significantly different progression rate between different statin medications (P = 0·801). However, patients taking pitavastatin (HR = 0·76, P = 0·657) were least likely to develop abnormal AST/ALT, whereas those taking fluvastatin (HR = 2·96, P = 0·029) were the most likely to develop abnormal AST/ALT compared with atorvastatin for patients who were with baseline borderline AST/ALT. However, given the small sample sizes and the observational nature of our study, these need further study. It is advisable to regularly monitor AST/ALT levels even in patients with AST/ALT increases >×1. Future studies should aim to determine the possible risk factors for each specific statin type by analysing various confounding variables. © 2016 The Authors. Journal of Clinical Pharmacy and Therapeutics Published by John Wiley & Sons Ltd.

  19. Human wild-type alanine:glyoxylate aminotransferase and its naturally occurring G82E variant: functional properties and physiological implications.

    PubMed

    Cellini, Barbara; Bertoldi, Mariarita; Montioli, Riccardo; Paiardini, Alessandro; Borri Voltattorni, Carla

    2007-11-15

    Human hepatic peroxisomal AGT (alanine:glyoxylate aminotransferase) is a PLP (pyridoxal 5'-phosphate)-dependent enzyme whose deficiency causes primary hyperoxaluria Type I, a rare autosomal recessive disorder. To acquire experimental evidence for the physiological function of AGT, the K(eq),(overall) of the reaction, the steady-state kinetic parameters of the forward and reverse reactions, and the pre-steady-state kinetics of the half-reactions of the PLP form of AGT with L-alanine or glycine and the PMP (pyridoxamine 5'-phosphate) form with pyruvate or glyoxylate have been measured. The results indicate that the enzyme is highly specific for catalysing glyoxylate to glycine processing, thereby playing a key role in glyoxylate detoxification. Analysis of the reaction course also reveals that PMP remains bound to the enzyme during the catalytic cycle and that the AGT-PMP complex displays a reactivity towards oxo acids higher than that of apoAGT in the presence of PMP. These findings are tentatively related to possible subtle rearrangements at the active site also indicated by the putative binding mode of catalytic intermediates. Additionally, the catalytic and spectroscopic features of the naturally occurring G82E variant have been analysed. Although, like the wild-type, the G82E variant is able to bind 2 mol PLP/dimer, it exhibits a significant reduced affinity for PLP and even more for PMP compared with wild-type, and an altered conformational state of the bound PLP. The striking molecular defect of the mutant, consisting in the dramatic decrease of the overall catalytic activity (approximately 0.1% of that of normal AGT), appears to be related to the inability to undergo an efficient transaldimination of the PLP form of the enzyme with amino acids as well as an efficient conversion of AGT-PMP into AGT-PLP. Overall, careful biochemical analyses have allowed elucidation of the mechanism of action of AGT and the way in which the disease causing G82E mutation affects

  20. Human wild-type alanine:glyoxylate aminotransferase and its naturally occurring G82E variant: functional properties and physiological implications

    PubMed Central

    Cellini, Barbara; Bertoldi, Mariarita; Montioli, Riccardo; Paiardini, Alessandro; Borri Voltattorni, Carla

    2007-01-01

    Human hepatic peroxisomal AGT (alanine:glyoxylate aminotransferase) is a PLP (pyridoxal 5′-phosphate)-dependent enzyme whose deficiency causes primary hyperoxaluria Type I, a rare autosomal recessive disorder. To acquire experimental evidence for the physiological function of AGT, the Keq,overall of the reaction, the steady-state kinetic parameters of the forward and reverse reactions, and the pre-steady-state kinetics of the half-reactions of the PLP form of AGT with L-alanine or glycine and the PMP (pyridoxamine 5′-phosphate) form with pyruvate or glyoxylate have been measured. The results indicate that the enzyme is highly specific for catalysing glyoxylate to glycine processing, thereby playing a key role in glyoxylate detoxification. Analysis of the reaction course also reveals that PMP remains bound to the enzyme during the catalytic cycle and that the AGT–PMP complex displays a reactivity towards oxo acids higher than that of apoAGT in the presence of PMP. These findings are tentatively related to possible subtle rearrangements at the active site also indicated by the putative binding mode of catalytic intermediates. Additionally, the catalytic and spectroscopic features of the naturally occurring G82E variant have been analysed. Although, like the wild-type, the G82E variant is able to bind 2 mol PLP/dimer, it exhibits a significant reduced affinity for PLP and even more for PMP compared with wild-type, and an altered conformational state of the bound PLP. The striking molecular defect of the mutant, consisting in the dramatic decrease of the overall catalytic activity (∼0.1% of that of normal AGT), appears to be related to the inability to undergo an efficient transaldimination of the PLP form of the enzyme with amino acids as well as an efficient conversion of AGT–PMP into AGT–PLP. Overall, careful biochemical analyses have allowed elucidation of the mechanism of action of AGT and the way in which the disease causing G82E mutation affects it

  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

    2013-12-04

    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.

  2. 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.

  3. Four of the Most Common Mutations in Primary Hyperoxaluria Type 1 Unmask the Cryptic Mitochondrial Targeting Sequence of Alanine:glyoxylate Aminotransferase Encoded by the Polymorphic Minor Allele*

    PubMed Central

    Fargue, Sonia; Lewin, Jackie; Rumsby, Gill; Danpure, Christopher J.

    2013-01-01

    The gene encoding the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT, EC. 2.6.1.44) exists as two common polymorphic variants termed the “major” and “minor” alleles. The P11L amino acid replacement encoded by the minor allele creates a hidden N-terminal mitochondrial targeting sequence, the unmasking of which occurs in the hereditary calcium oxalate kidney stone disease primary hyperoxaluria type 1 (PH1). This unmasking is due to the additional presence of a common disease-specific G170R mutation, which is encoded by about one third of PH1 alleles. The P11L and G170R replacements interact synergistically to reroute AGT to the mitochondria where it cannot fulfill its metabolic role (i.e. glyoxylate detoxification) effectively. In the present study, we have reinvestigated the consequences of the interaction between P11L and G170R in stably transformed CHO cells and have studied for the first time whether a similar synergism exists between P11L and three other mutations that segregate with the minor allele (i.e. I244T, F152I, and G41R). Our investigations show that the latter three mutants are all able to unmask the cryptic P11L-generated mitochondrial targeting sequence and, as a result, all are mistargeted to the mitochondria. However, whereas the G170R, I244T, and F152I mutants are able to form dimers and are catalytically active, the G41R mutant aggregates and is inactive. These studies open up the possibility that all PH1 mutations, which segregate with the minor allele, might also lead to the peroxisome-to-mitochondrion mistargeting of AGT, a suggestion that has important implications for the development of treatment strategies for PH1. PMID:23229545

  4. Opposite effect of polymorphic mutations on the electrostatic aggregation of human alanine:glyoxylate aminotransferase: implications for the pathogenesis of Primary Hyperoxaluria Type I.

    PubMed

    Dindo, Mirco; Conter, Carolina; Cellini, Barbara

    2017-09-14

    Protein aggregates formation is the basis of several misfolding diseases, including those displaying loss-of-function pathogenesis. Although aggregation is often attributed to the population of intermediates exposing hydrophobic surfaces, the contribution of electrostatic forces has recently gained attention. Here we combined computational and in vitro studies to investigate the aggregation process of human peroxisomal alanine:glyoxylate aminotransferase (AGT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme involved in glyoxylate detoxification. We demonstrated that AGT is susceptible to electrostatic aggregation due to its peculiar surface charge anisotropy, and that PLP binding counteracts the self-association process. The two polymorphic mutations P11L and I340M exert opposite effects. The P11L substitution enhances the aggregation tendency, by probably increasing surface charge anisotropy, while the I340M plays a stabilizing role. In light of these results, we examined the effects of the most common missense mutations leading to Primary Hyperoxaluria Type I (PH1), a rare genetic disorder associated with abnormal calcium oxalate precipitation in the urinary tract. All of them endow AGT with a strong electrostatic aggregation propensity. Moreover, we predicted that pathogenic mutations of surface residues could alter charge distribution, thus inducing aggregation under physiological conditions. A global model describing the AGT aggregation process is provided. Overall, the results indicate that the contribution of electrostatic interactions in determining the fate of proteins as well as the effect of amino acid substitutions should not be underestimated, and provide the basis for the development of new therapeutic strategies for PH1 aimed at increasing AGT stability. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. 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.

  6. Elevation of Alanine Aminotransferase Activity Occurs after Activation of the Cell-Death Signaling Initiated by Pattern-Recognition Receptors ‎but before Activation of Cytolytic Effectors in NK or CD8+ T Cells in the Liver During Acute HCV Infection

    PubMed Central

    Choi, Youkyung H.; Jin, Nancy; Kelly, Fiona; Sakthivel, SenthilKumar K.; Yu, Tianwei

    2016-01-01

    Pattern-recognition receptors (PRRs) promote host defenses against HCV infection by binding to their corresponding adapter molecules leading to the initiation of innate immune responses including cell death. We investigated the expression of PRR genes, biomarkers of liver cell-death, and T cell and NK cell activation/inhibition-related genes in liver and serum obtained from three experimentally infected chimpanzees with acute HCV infection, and analyzed the correlation between gene expression levels and clinical profiles. Our results showed that expression of hepatic RIG-I, TLR3, TLR7, 2OAS1, and CXCL10 mRNAs was upregulated as early as 7 days post-inoculation and peaked 12 to 83 days post-inoculation. All of the three HCV infected chimpanzees exhibited significant elevations of serum alanine aminotransferase (ALT) activity between 70 and 95 days after inoculation. Elevated levels of serum cytokeratin 18 (CK-18) and caspases 3 and 7 activity coincided closely with the rise of ALT activity, and were preceded by significant increases in levels of caspase 3 and caspase 7 mRNAs in the liver. Particularly we found that significant positive auto-correlations were observed between RIG-I, TLR3, CXCL10, 2OAS1, and PD-L1 mRNA and ALT activity at 3 to 12 days before the peak of ALT activity. However, we observed substantial negative auto-correlations between T cell and NK cell activation/inhibition-related genes and ALT activity at 5 to 32 days after the peak of ALT activity. Our results indicated cell death signaling is preceded by early induction of RIG-I, TLR3, 2OAS1, and CXCL10 mRNAs which leads to elevation of ALT activity and this signaling pathway occurs before the activation of NK and T cells during acute HCV infection. Our study suggests that PRRs and type I IFN response may play a critical role in development of liver cell injury related to viral clearance during acute HCV infection. PMID:27788241

  7. L-alanine-glyoxylate aminotransferase II of rat kidney and liver mitochondria possesses cysteine S-conjugate beta-lyase activity: a contributing factor to the nephrotoxicity/hepatotoxicity of halogenated alkenes?

    PubMed Central

    Cooper, Arthur J L; Krasnikov, Boris F; Okuno, Etsuo; Jeitner, Thomas M

    2003-01-01

    Several halogenated alkenes are metabolized in part to cysteine S-conjugates, which are mitochondrial toxicants of kidney and, to a lesser extent, other organs. Toxicity is due to cysteine S-conjugate beta-lyases, which convert the cysteine S-conjugate into pyruvate, ammonia and a reactive sulphur-containing fragment. A section of the human population is exposed to halogenated alkenes. To understand the health effects of such exposure, it is important to identify cysteine S-conjugate beta-lyases that contribute to mitochondrial damage. Mitochondrial aspartate aminotransferase [Cooper, Bruschi, Iriarte and Martinez-Carrion (2002) Biochem. J. 368, 253-261] and mitochondrial branched-chain aminotransferase [Cooper, Bruschi, Conway and Hutson (2003) Biochem. Pharmacol. 65, 181-192] exhibit beta-lyase activity toward S -(1,2-dichlorovinyl)-L-cysteine (the cysteine S-conjugate of trichloroethylene) and S -(1,1,2,2-tetrafluoroethyl)-L-cysteine (the cysteine S-conjugate of tetrafluoroethylene). Turnover leads to eventual inactivation of these enzymes. Here we report that mitochondrial L-alanine-glyoxylate aminotransferase II, which, in the rat, is most active in kidney, catalyses cysteine S-conjugate beta-lyase reactions with S -(1,1,2,2-tetrafluoroethyl)-L-cysteine, S -(1,2-dichlorovinyl)-L-cysteine and S -(benzothiazolyl-L-cysteine); turnover leads to inactivation. Previous workers showed that the reactive-sulphur-containing fragment released from S -(1,1,2,2-tetrafluoroethyl)-L-cysteine and S -(1,2-dichlorovinyl)-L-cysteine is toxic by acting as a thioacylating agent - particularly of lysine residues in nearby proteins. Toxicity, however, may also involve 'self-inactivation' of key enzymes. The present findings suggest that alanine-glyoxylate aminotransferase II may be an important factor in the well-established targeting of rat kidney mitochondria by toxic halogenated cysteine S-conjugates. Previous reports suggest that alanine-glyoxylate aminotransferase II is absent

  8. 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

  9. 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

  10. 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

  11. Detection of TTV in peripheral blood cells from patients with altered ALT and AST levels.

    PubMed

    de Oliveira, Jaqueline Carvalho; Nasser, Thiago Franco; Oda, Julie Massayo Maeda; Aoki, Mateus Nóbrega; Carneiro, Juliana Laino do Val; Barbosa, Décio Sabbatini; Reiche, Edna Maria Vissoci; Watanabe, Maria Angelica Ehara

    2008-04-01

    This work analyzes the prevalence of TTV DNA in peripheral blood cells from patients with hepatic alterations and healthy blood donors and measures levels of sodium, potassium, urea, creatinine, phosphatase alkaline, total and direct bilirubin, gamma glutamyl transferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in certain randomly selected patients. DNA samples from 111 individuals were evaluated. They were divided into two groups, "A" (study) and "B" (control), including 54 patients with liver enzyme alterations (ALT/AST) presenting non-B-non-C hepatitis and 57 blood donors, respectively. TTV DNA was determined by nested PCR. Certain products of the second-round PCR were sequenced. Serum biochemical assay was performed and disclosed TTV in 31.48% (17/54) of patients in group A and 5.26% (3/57) in the control group B. TTV prevalence was significantly higher in patients with liver disease than in healthy donors. In group A, sodium, potassium, urea, creatinine, phosphatase alkaline, total and direct bilirubin, gamma glutamyl transferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were analyzed in certain randomly selected patients and no significant difference in biochemical levels (p>0.05) was found when TTV infected and noninfected individuals were compared. Knowledge related to TTV has rapidly increased, but many fundamental aspects remain unclear. This led us to question the role of TTV and doubt remains as to whether or not it is just a commensal virus. Further studies are necessary to confirm and extend these findings.

  12. Association of ALT and the metabolic syndrome among Mexican children.

    PubMed

    Elizondo-Montemayor, Leticia; Ugalde-Casas, Patricia A; Lam-Franco, Lorena; Bustamante-Careaga, Humberto; Serrano-González, Mónica; Gutiérrez, Norma G; Martínez, Ubaldo

    2014-01-01

    Nonalcoholic fatty liver disease (NAFLD) is emerging as a component of the metabolic syndrome (MetS); Hispanics being particularly predisposed. Alanine aminotransferase (ALT) is considered a marker of NAFLD. The aim of this study was to determine the prevalence and associations between ALT elevations and MetS in normal-weight, overweight and obese Mexican children and adolescents, since data in Mexico is scarce. Body mass index (BMI), waist circumference (WC), percentage body fat, blood pressure, glucose, lipid profiles, ALT and aspartate aminotransferase (AST) were measured in 236, 6-12yo normal-weight, overweight and obese Mexicans from eight public schools. The results showed that elevated ALT (>40 IU/L) was found in 17.7% of the obese and overweight population, with no gender difference. The prevalence of elevated ALT increased linearly across BMI categories (p = 0.001), from 0.0% for the normal-weight group (95%CI 0.0-€“8.0) to 22.4% for the obese one (95%CI 16.2-€“30.2). AST/ALT ratio <1 also increased linearly, as did the prevalence of MetS (p = 0.001), from 0.0% for the normal-weight group to 40.3% for the obese one. The prevalence of MetS was strongly associated with elevated ALT (p = 0.002), 50% in the elevated ALT group (95%CI 34.1-€“65.9) and 24.1% in the normal ALT one (95%CI 18.1-€“31.3). There was also a strong association between MetS and an AST/ALT ratio <1. WC was the best predictor of elevated ALT (AOR = 7.13). Pearson correlation showed that MetS components were significantly correlated with elevated ALT. Therefore elevated ALT levels were highly prevalent and strongly associated with MetS in Mexican children, it should be screened in overweight and obese children.

  13. A pre-marketing ALT signal predicts post-marketing liver safety.

    PubMed

    Moylan, Cynthia A; Suzuki, Ayako; Papay, Julie I; Yuen, Nancy A; Ames, Michael; Hunt, Christine M

    2012-08-01

    Drug induced liver injury during drug development is evidenced by a higher incidence of serum alanine aminotransferase (ALT) elevations in treated versus placebo populations and termed an "ALT signal". We sought to quantify whether an ALT signal in pre-marketing clinical trials predicted post-marketing hepatotoxicity. Incidence of ALT elevations (ALT ≥ 3 times upper limits normal [× ULN]) for drug and placebo of new chemical entities and approved drugs associated with hepatotoxicity was calculated using the Food and Drug Administration (FDA) website. Post-marketing liver safety events were identified using the FDA Adverse Event Reporting System (AERS). The association of FDA AERS signal score (EB05 ≥ 2) and excess risk of pre-marketing ALT elevation (difference in incidence of ALT ≥ 3× ULN in treated versus placebo) was examined. An ALT signal of ≥ 1.2% was significantly associated with a post-marketing liver safety signal (p ≤ 0.013) and a 71.4% positive predictive value. An absent ALT signal was associated with a high likelihood of post-marketing liver safety; negative predictive value of 89.7%. Daily drug dose information improved the prediction of post-marketing liver safety. A cut-off of 1.2% increase in ALT ≥ 3× ULN in treated versus placebo groups provides an easily calculated method for predicting post-marketing liver safety.

  14. The Effect of Acetaminophen on Serum Alanine Aminotransferase Activity in Subjects Who Consume Ethanol: A Systematic Review and Meta-analysis of Published Randomized, Controlled Trials

    PubMed Central

    Rumack, B; Heard, K; Green, J; Albert, D; Bucher Bartelson, B; Bodmer, M; Sivilotti, MLA; Dart, RC

    2012-01-01

    Study Objective To quantify the effect of acetaminophen at therapeutic doses on serum ALT in subjects who use ethanol, using data from all randomized placebo-controlled trials (RCT). Design A systematic review and meta-analysis of RCTs identified in a comprehensive literature search of PubMed EMBASE, International Pharmaceutical Abstracts and the Cochrane Registry of Clinical Trials. The search included multiple terms for “acetaminophen” combined with multiple terms for “ethanol”. Patients We included RCT that enrolled subjects who had consumed ethanol either during or just prior to study entry, and who were administered up to 4 g daily of acetaminophen. Measurements The primary outcome was the change in serum ALT activity from baseline compared to placebo. Main Results 184 unique articles were identified; six articles met all criteria. Five of the six articles reported ALT values at study day 4 for 551 acetaminophen-treated and 350 placebo-treated subjects; thus the changes in ALT from baseline to study day 4 were used for the meta-analysis. The difference in mean change from baseline ALT values between the acetaminophen and placebo groups on study day 4 was 0.0 IU/L (95%CI: −0.2 to 0.1 IU/L). There were no reports of liver dysfunction, failure or death in any of the prospective trials. Conclusion In published randomized, placebo controlled trials of subjects who consume ethanol, there was no elevation of ALT on study day four when subjects ingest 4g/day of acetaminophen. PMID:22851428

  15. The Relationships between Respiratory Virus Infection and Aminotransferase in Children

    PubMed Central

    Oh, Jun Suk; Choi, Jun Sik; Lee, Young Hyuk; Ko, Kyung Og; Lim, Jae Woo; Cheon, Eun Jung; Lee, Gyung Min

    2016-01-01

    Purpose We sought to examine the relationship between the clinical manifestations of nonspecific reactive hepatitis and respiratory virus infection in pediatric patients. Methods Patients admitted to the pediatric unit of Konyang University Hospital for lower respiratory tract disease between January 1, 2014 and December 31, 2014 and who underwent reverse transcriptase polymerase chain reaction tests were examined. The patients were divided into those with increased levels of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) and those with normal ALT or AST levels. Further, patients with increased ALT and AST levels were individually compared with patients in the normal group, and the blood test results were compared according to the type of respiratory virus. Results Patients with increased ALT or AST levels had one more day of hospital stay, on average, compared with patients in the normal group (5.3±3.1 days vs. 4.4±3.0 days, p=0.019). Patients in the increased ALT level group were younger and had a longer mean hospital stay, compared with patients in the normal group (p=0.022 and 0.003, respectively). The incidences of increased ALT or AST were the highest in adenovirus infections (6/24, 25.0%), followed by enterovirus (2/11, 18.2%) and respiratory syncytial virus A (21/131, 16.0%) infections. Conclusion Nonspecific reactive hepatitis is more common among patients with adenovirus, enterovirus and respiratory syncytial virus infection, as well as among those infected at a younger age. Compared with AST levels, ALT levels are better indicators of the severity of nonspecific reactive hepatitis. PMID:28090469

  16. Aspartate aminotransferase (AST) blood test

    MedlinePlus

    ... 2016:chap 73. Read More Acute kidney failure Acute pancreatitis Alanine transaminase (ALT) blood test ALP - blood test Burns Cardiac catheterization Enzyme Heart attack Hemolytic anemia Hepatic Liver cancer - hepatocellular carcinoma Liver ...

  17. Comparison of Histologic Characteristics of Chinese Chronic Hepatitis B Patients with Persistently Normal or Mildly Elevated ALT

    PubMed Central

    Wang, Hong; Xue, Li; Yan, Rong; Zhou, Yin; Wang, Ming-Shan; Cheng, Mei-Juan; Hai-Jun Huang

    2013-01-01

    Liver disease can develop in chronic hepatitis B (CHB) patients with normal or mildly elevated alanine aminotransferase (ALT) who seldom undergo liver biopsy. We aimed to determine histologic characteristics of a large cohort of Chinese CHB patients undergoing liver biopsy and to evaluate the utility of ALT and HBV DNA values at the time of biopsy in predicting liver disease in this population. This prospective study enrolled 230 treatment-naïve patients with persistently normal or mildly elevated ALT. All patients had a liver biopsy. ALT, aspartate aminotransferase (AST), and HBV DNA levels were some of the other parameters measured. Using Scheuer's classification, significant histology was defined as stage ≧2 fibrosis and/or stage 1 fibrosis plus≧ grade 2 inflammation. Liver disease was observed in 34.4% and 61.8% of patients with normal ALT and mildly elevated ALT, respectively. Patients with mildly elevated ALT levels had significantly more events, including liver disease, elevated AST, and moderate to severe inflammation and liver fibrosis, than patients with normal ALT (all P≤0.005). A total of 107 patients (46.5%) had liver disease and 123 (53.5%) did not. PLT and ALT were significantly associated with liver disease (both P<0.001). Patients with elevated ALT, lower platelet count and HBV DNA < 7 log10copies/mL may have histologically significant changes associated with liver disease. Multivariate analysis showed that PLT and HBV DNA levels were significantly associated with liver disease in patients with normal ALT while gender and HBV DNA levels were significantly associated with liver disease in patients with mildly elevated ALT. Assessing liver damage via biopsy in patients with normal or mildly elevated ALT may help to identify those who would benefit from antiviral therapy. PMID:24260428

  18. Salivary lactate dehydrogenase and aminotransferases in diabetic patients

    PubMed Central

    Malicka, Barbara; Skoskiewicz-Malinowska, Katarzyna; Kaczmarek, Urszula

    2016-01-01

    Abstract Diabetes mellitus (DM) is a group of metabolic diseases resulting from impaired insulin secretion and/or action. DM is characterized by hyperglycemia that can lead to the dysfunction or damage of organs, including the salivary glands. The aim of this study was to compare the levels of salivary lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in diabetic patients. The study was approved by the Bioethics Committee of Wroclaw Medical University (Poland). The study comprised 90 adults of both sexes, aged 21 to 57 years. The patients were divided into 3 groups: type 1 diabetics (D1), type 2 diabetics (D2), and a healthy control group (C). Each group consisted of 30 age- and sex-matched subjects. Total protein (P, by Lowry method), LDH, AST, ALT (with Alpha Diagnostics kits), and salivary flow rate were measured in unstimulated mixed saliva. The level of glycosylated hemoglobin (HbA1c) was measured with DCA 2000 Reagent Kit. The obtained data were analyzed using the Mann–Whitney U test and the Spearman rank at a significance level of P < 0.05 with the use of STATISTICA 9.0 software. In comparison with C, D1 presented a significantly higher activity of LDH (P < 0.001), AST (P < 0.001), and ALT (P < 0.01), whereas D2 indicated higher levels of LDH (P < 0.001) and ALT (P < 0.05) compared with C. Comparing D1 to D2, approximately 3-fold higher activity of AST (P < 0.01) and approximately 4.5-fold higher activity of ALT (P < 0.01) was observed. Higher levels of salivary LDH, AST, and ALT in D1 compared with D2 and C confirm that salivary glands of D1 might be attributed to autoimmunological damage associated with the pathomechanism of DM. PMID:27893660

  19. 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

  20. 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

  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

    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.

  2. An assessment of racial differences in the upper limits of normal ALT levels in children and the effect of obesity on elevated values.

    PubMed

    Kliethermes, S; Ma, M; Purtell, C; Balasubramanian, N; Gonzalez, B; Layden, T J; Cotler, S J

    2017-10-01

    Childhood obesity is a risk factor for non-alcoholic fatty liver disease and poses important public health issues for children. Racial differences in alanine aminotransferase (ALT) levels among children have not been described. This study aimed to identify racial differences in upper limit normal (ULN) ALT levels and evaluate the effect of obesity on elevated levels in children without other metabolic risk factors. National Health and Nutrition Examination Surveys and clinical data from the Loyola University Health System were used to determine ULN ALT by race and gender. Quantile regression was used to evaluate the impact of obesity on elevated ALT and to identify potential risk factors for ALT above the ULN. Upper limit normal (ULN) ALT was approximately 28.0 and 21.0-24.0 U/L for boys and girls, respectively. No significant difference in ULN ALT across race was observed. Obesity was significantly associated with elevated ALT; obese children with elevated ALT had values 10 U/L higher than normal-weight children. Racial differences in ALT levels among adults are not evident in children. Obesity, in the absence of metabolic risk factors and other causes of liver disease, is associated with elevated ALT, providing evidence against the concept of healthy obesity in children. © 2016 World Obesity Federation.

  3. Serum aminotransferase level and the risk of hepatocellular carcinoma: a population-based cohort study in Japan.

    PubMed

    Ishiguro, Seiji; Inoue, Manami; Tanaka, Yasuhito; Mizokami, Masashi; Iwasaki, Motoki; Tsugane, Shoichiro

    2009-02-01

    Aminotransferase level is presumed to be a marker of hepatic inflammation, but uncertainty remains whether elevated aminotransferase levels are associated with an increased risk of hepatocellular carcinoma (HCC). We evaluated the incidence of HCC by aminotransferase level in 19 812 middle-aged and older individuals with and without hepatitis virus infection from a large-scale population-based cohort study (JPHC Study cohort II) in Japan. Hepatitis virus infection was identified at baseline in 1236 participants, namely 737 (3.7%) with hepatitis C virus, 479 (2.4%) with hepatitis B virus, and 20 (0.1%) with both. By the end of follow-up, a total of 109 newly arising HCC cases were diagnosed (71 men, 38 women), of which 87 (79.8%) had evidence of viral etiology. Alanine aminotransferase (ALT) was concentration-dependently associated with an increased risk of HCC in both virus-positive and virus-negative participants. Compared with virus-negative participants with ALT levels of less than 30 IU/l, a significant increase in the risk of HCC was observed in virus-negative participants with an ALT level greater than 30 IU/l, and in virus-positive participants with an ALT less than 30 IU/l, 30-69 IU/l, and > or =70 IU/l [Hazard ratio (95% confidence interval): 9.4 (3.9-22.3), 15.2 (6.1-37.6), 180.5 (89.4-364.2), 454.2 (221.5-931.2), respectively; P for trend <0.001]. In conclusion, our findings suggest that elevated ALT levels are strongly associated with the incidence of HCC regardless of hepatitis virus positivity. This finding indicates that ALT level is a good independent determinant of the need for intervention. Clinical application of these findings may help decrease HCC-associated mortality in hepatitis virus-endemic regions.

  4. The 'donations for decreased ALT (D4D)' prosocial behavior incentive scheme for NAFLD patients.

    PubMed

    Sumida, Yoshio; Yoshikawa, Toshikazu; Tanaka, Saiyu; Taketani, Hiroyoshi; Kanemasa, Kazuyuki; Nishimura, Tekeshi; Yamaguchi, Kanji; Mitsuyoshi, Hironori; Yasui, Kohichiroh; Minami, Masahito; Naito, Yuji; Itoh, Yoshito

    2014-12-01

    Physicians often experience difficulties in motivating patients with non-alcoholic fatty liver disease (NAFLD) to undergo lifestyle changes. The aim of this study is to examine whether 'Donations for Decreased alanine aminotransferase (ALT)' (D4D) prosocial behavior incentive can serve as an effective intrinsic motivational factor in comparison with conventional dietary and exercise intervention alone for NAFLD patients. Twenty-five NAFLD patients with elevated ALT were randomly assigned to a control group that received conventional dietary and exercise intervention alone, or a donation group whereby, as an incentive, we would make a monetary donation to the United Nations World Food Programme (WFP) based on the decrease in their ALT levels achieved over 12 weeks, in addition to receiving control intervention. In a donation group, we would donate US$1 to the WFP for every 1 IU/l of decrease in their ALT levels. There were no differences of pre-treatment clinical characteristics between the two groups. Significant reductions of ALT levels were achieved only in a donation group, although post-treatment ALT levels were not different between the two groups. These patients raised a total of $316 for the WFP. Promoting patients' intrinsic motivation by incorporating 'D4D' prosocial behavior incentive into conventional dietary and exercise intervention may provide a means to improve NAFLD. © The Author 2013. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. The past and present of serum aminotransferases and the future of liver injury biomarkers

    PubMed Central

    McGill, Mitchell R.

    2016-01-01

    Laboratory testing is important in the diagnosis and monitoring of liver injury and disease. Current liver tests include plasma markers of injury (e.g. aminotransferases, γ-glutamyl transferase, and alkaline phosphatase), markers of function (e.g. prothrombin time, bilirubin), viral hepatitis serologies, and markers of proliferation (e.g. α-fetoprotein). Among the injury markers, the alanine and aspartate aminotransferases (ALT and AST, respectively) are the most commonly used. However, interpretation of ALT and AST plasma levels can be complicated. Furthermore, both have poor prognostic utility in acute liver injury and liver failure. New biomarkers of liver injury are rapidly being developed, and the US Food and Drug Administration the European Medicines Agency have recently expressed support for use of some of these biomarkers in drug trials. The purpose of this paper is to review the history of liver biomarkers, to summarize mechanisms and interpretation of ALT and AST elevation in plasma in liver injury (particularly acute liver injury), and to discuss emerging liver injury biomarkers that may complement or even replace ALT and AST in the future. PMID:28337112

  6. Aminotransferase elevations in rotavirus positive and negative acute gastroenteritis and its relation with disease severity.

    PubMed

    Işik, Ishak; Tokgöz, Yavuz; Erdur, Barış; Arslan, Nur

    2017-02-01

    The aim of this study was to investigate the frequency of elevated alanine (ALT) and aspartate aminotransferase (AST) levels in children with rotavirus positive and negative gastroenteritis as well as the average time to normalization of liver enzymes. Into the study 298 patients with rotavirus positive and 321 patients with rotavirus negative gastroenteritis were enrolled. Mean AST (56.9±2.1 and 40.2±0.9 U/L, respectively, P=0.000) and ALT (33.1±1.7 and 22.4±0.8 U/L, respectively, P=0.000) levels were significantly higher in the rotavirus positive than rotavirus negative patients. Logistic regression analysis showed that rotavirus positivity was significant independent factor for both AST and ALT elevation. Severity of gastroenteritis was another significant independent factor for ALT elevation. The average transaminase normalization time for AST and ALT levels were similar both rotavirus positive and negative groups. Rotavirus positivity and severity of gastroenteritis were independent risk factors for elevated ALT levels in children with gastroenteritis.

  7. Coffee consumption is associated with lower serum aminotransferases in the general Korean population and in those at high risk for hepatic disease.

    PubMed

    Oh, Myueng Guen; Han, Mi Ah; Kim, Man Woo; Park, Chan Guk; Kim, Young Dae; Lee, Jun

    2016-12-01

    The favourable effects of coffee on liver enzymes have been reported worldwide. This study investigated the association between coffee consumption and serum aminotransferase concentration in Korean adults. Data were obtained from the fourth and fifth Korea National Health and Nutrition Examination Surveys. Elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentration were defined as >30 IU/L for men and >19 IU/L for women. The risk of elevated ALT and AST according to general characteristics and frequency of coffee consumption were tested by chi-square tests and multiple logistic regression analyses. The prevalence of elevated ALT was 27.4%, 27.8%, and 26.9% in subjects who drank <1, 1, and >=2 times/day, respectively. The proportions of individuals with elevated AST were 32.5%, 33.1%, and 26.7% in subjects who drank <1, 1, and >=2 times/day, respectively. The aORs for elevated ALT and AST were significantly lower in subjects who drank >=2 times of coffee/day than in those who drank <1 time/day (ALT: aOR=0.86, 95% CI=0.79-0.94; AST: aOR=0.83, 95% CI=0.76-0.91). In subgroup analysis, consumption of >=2 times/day was associated with lower ORs for elevated ALT in the high-risk group overall and in the viral hepatitis and obesity subgroups, respectively. In sensitivity analysis, reduced frequency of coffee consumption was associated with an increased risk for elevated liver enzymes, although an association between coffee consumption and elevated ALT was not observed in women or current smokers. Higher coffee consumption was associated with lower risk of elevated aminotransferase concentration in Korean adults.

  8. Incremental Predictive Value of Serum AST-to-ALT Ratio for Incident Metabolic Syndrome: The ARIRANG Study

    PubMed Central

    Ahn, Song Vogue; Baik, Soon Koo; Cho, Youn zoo; Koh, Sang Baek; Huh, Ji Hye; Chang, Yoosoo; Sung, Ki-Chul; Kim, Jang Young

    2016-01-01

    Aims The ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) is of great interest as a possible novel marker of metabolic syndrome. However, longitudinal studies emphasizing the incremental predictive value of the AST-to-ALT ratio in diagnosing individuals at higher risk of developing metabolic syndrome are very scarce. Therefore, our study aimed to evaluate the AST-to-ALT ratio as an incremental predictor of new onset metabolic syndrome in a population-based cohort study. Material and Methods The population-based cohort study included 2276 adults (903 men and 1373 women) aged 40–70 years, who participated from 2005–2008 (baseline) without metabolic syndrome and were followed up from 2008–2011. Metabolic syndrome was defined according to the harmonized definition of metabolic syndrome. Serum concentrations of AST and ALT were determined by enzymatic methods. Results During an average follow-up period of 2.6-years, 395 individuals (17.4%) developed metabolic syndrome. In a multivariable adjusted model, the odds ratio (95% confidence interval) for new onset of metabolic syndrome, comparing the fourth quartile to the first quartile of the AST-to-ALT ratio, was 0.598 (0.422–0.853). The AST-to-ALT ratio also improved the area under the receiver operating characteristic curve (AUC) for predicting new cases of metabolic syndrome (0.715 vs. 0.732, P = 0.004). The net reclassification improvement of prediction models including the AST-to-ALT ratio was 0.23 (95% CI: 0.124–0.337, P<0.001), and the integrated discrimination improvement was 0.0094 (95% CI: 0.0046–0.0143, P<0.001). Conclusions The AST-to-ALT ratio independently predicted the future development of metabolic syndrome and had incremental predictive value for incident metabolic syndrome. PMID:27560931

  9. Incremental Predictive Value of Serum AST-to-ALT Ratio for Incident Metabolic Syndrome: The ARIRANG Study.

    PubMed

    Yadav, Dhananjay; Choi, Eunhee; Ahn, Song Vogue; Baik, Soon Koo; Cho, Youn Zoo; Koh, Sang Baek; Huh, Ji Hye; Chang, Yoosoo; Sung, Ki-Chul; Kim, Jang Young

    2016-01-01

    The ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) is of great interest as a possible novel marker of metabolic syndrome. However, longitudinal studies emphasizing the incremental predictive value of the AST-to-ALT ratio in diagnosing individuals at higher risk of developing metabolic syndrome are very scarce. Therefore, our study aimed to evaluate the AST-to-ALT ratio as an incremental predictor of new onset metabolic syndrome in a population-based cohort study. The population-based cohort study included 2276 adults (903 men and 1373 women) aged 40-70 years, who participated from 2005-2008 (baseline) without metabolic syndrome and were followed up from 2008-2011. Metabolic syndrome was defined according to the harmonized definition of metabolic syndrome. Serum concentrations of AST and ALT were determined by enzymatic methods. During an average follow-up period of 2.6-years, 395 individuals (17.4%) developed metabolic syndrome. In a multivariable adjusted model, the odds ratio (95% confidence interval) for new onset of metabolic syndrome, comparing the fourth quartile to the first quartile of the AST-to-ALT ratio, was 0.598 (0.422-0.853). The AST-to-ALT ratio also improved the area under the receiver operating characteristic curve (AUC) for predicting new cases of metabolic syndrome (0.715 vs. 0.732, P = 0.004). The net reclassification improvement of prediction models including the AST-to-ALT ratio was 0.23 (95% CI: 0.124-0.337, P<0.001), and the integrated discrimination improvement was 0.0094 (95% CI: 0.0046-0.0143, P<0.001). The AST-to-ALT ratio independently predicted the future development of metabolic syndrome and had incremental predictive value for incident metabolic syndrome.

  10. 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

  11. Wilson disease in children: serum aminotransferases and urinary copper on triethylene tetramine dihydrochloride (trientine) treatment.

    PubMed

    Arnon, Ronen; Calderon, Judith Flores; Schilsky, Michael; Emre, Sukru; Shneider, Benjamin L

    2007-05-01

    To evaluate the efficacy of and adherence to trientine and/or zinc therapy in children with Wilson disease (WD). We retrospectively reviewed the clinical records of all children with WD in the pediatric liver/liver transplant program at our institution between 1998 and 2006. A total of 22 children with WD were evaluated and treated. Seven with fulminant disease required liver transplantation and 15 were treated with trientine and/or zinc. Ten of those 15 had follow-up for 12 to 60 months and 6 of the latter 10 were followed for 12 to 18 months. All 10 patients were started on a trientine treatment regimen. Mean alanine aminotransferase (ALT) levels decreased from 183 +/- 103 IU at presentation (n = 10) to 80 +/- 46 IU at 12 months (n = 10) and 66 +/- 40 IU at 18 months (n = 7). Mean 24-hour urinary copper levels increased from 156 microg at presentation to 494 microg at 1 to 2 months, then decreased to 71 microg after 21 to 24 months of treatment. Three of 10 patients had normalized ALT levels and 1 patient with cirrhosis continued with normal ALT levels since presentation. Four of 10 patients were documented to be nonadherent, as manifested by increased ALT levels (99 +/- 31 IU); 1 patient had previously normalized ALT levels. In 3 of 10 patients, ALT level decreased but remained at an abnormal level (93 +/- 53 IU). Trientine and/or zinc therapy is effective for children with WD. Nonadherence is a common cause of increased aminotransferase levels in patients with WD.

  12. Regional Adipose Tissue and Elevations in Serum Aminotransferases in HIV-Infected Individuals

    PubMed Central

    Tien, Phyllis C.; Kotler, Donald P.; Overton, E. Turner; Lewis, Cora E.; Rimland, David; Bacchetti, Peter; Scherzer, Rebecca; Gripshover, Barbara

    2009-01-01

    Background The association of fat distribution with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevations is not well-defined in HIV-infected individuals. Obesity is associated with hepatic steatosis, and ALT is a marker of steatosis in the general population. Methods Cross-sectional analysis of 1119 HIV-infected and 284 control subjects. Hepatitis C virus (HCV) RNA testing determined HCV infection. Magnetic resonance imaging measured regional adipose tissue volume. Results After adjustment for demographic and lifestyle factors, visceral adipose tissue (VAT) was positively associated with ALT in HIV/HCV-coinfected subjects (+9.8%, 95% confidence interval [CI]: 2.8 to 17.6), HIV-monoinfected subjects (+8.0%, 95% CI: 4.2 to 12.1), and controls (+5.9%, 95% CI: 2.0 to 10.1). In contrast, lower trunk subcutaneous adipose tissue (SAT) was negatively associated with ALT in HIV/HCV-coinfected subjects (−14.3%, 95% CI: −24.7 to −4.2) and HIV-monoinfected subjects (−11.9%, 95% CI: −18.4 to −5.3); there was a trend toward an association in controls (−7.1%, 95% CI: −22.7 to 5.9). Estimated associations between regional adipose tissue and AST were small and did not reach statistical significance. Conclusions More VAT and less lower trunk SAT are associated with elevated ALT, which likely reflects the presence of steatosis. There was little association with AST. HCV infection and having more VAT or less lower trunk SAT are independently associated with elevated ALT in HIV infection. Study regarding the association between VAT, trunk SAT, HCV, and progression of steatosis and fibrosis is needed in HIV-infected individuals. PMID:18285711

  13. Evolutionary Diversification of Alanine Transaminases in Yeast: Catabolic Specialization and Biosynthetic Redundancy

    PubMed Central

    Escalera-Fanjul, Ximena; Campero-Basaldua, Carlos; Colón, Maritrini; González, James; Márquez, Dariel; González, Alicia

    2017-01-01

    Gene duplication is one of the major evolutionary mechanisms providing raw material for the generation of genes with new or modified functions. The yeast Saccharomyces cerevisiae originated after an allopolyploidization event, which involved mating between two different ancestral yeast species. ScALT1 and ScALT2 codify proteins with 65% identity, which were proposed to be paralogous alanine transaminases. Further analysis of their physiological role showed that while ScALT1 encodes an alanine transaminase which constitutes the main pathway for alanine biosynthesis and the sole pathway for alanine catabolism, ScAlt2 does not display alanine transaminase activity and is not involved in alanine metabolism. Moreover, phylogenetic studies have suggested that ScALT1 and ScALT2 come from each one of the two parental strains which gave rise to the ancestral hybrid. The present work has been aimed to the understanding of the properties of the ancestral type Lacchancea kluyveri LkALT1 and Kluyveromyces lactis KlALT1, alanine transaminases in order to better understand the ScALT1 and ScALT2 evolutionary history. These ancestral -type species were chosen since they harbor ALT1 genes, which are related to ScALT2. Presented results show that, although LkALT1 and KlALT1 constitute ScALT1 orthologous genes, encoding alanine transaminases, both yeasts display LkAlt1 and KlAlt1 independent alanine transaminase activity and additional unidentified alanine biosynthetic and catabolic pathway(s). Furthermore, phenotypic analysis of null mutants uncovered the fact that KlAlt1 and LkAlt1 have an additional role, not related to alanine metabolism but is necessary to achieve wild type growth rate. Our study shows that the ancestral alanine transaminase function has been retained by the ScALT1 encoded enzyme, which has specialized its catabolic character, while losing the alanine independent role observed in the ancestral type enzymes. The fact that ScAlt2 conserves 64% identity with LkAlt1

  14. Evolutionary Diversification of Alanine Transaminases in Yeast: Catabolic Specialization and Biosynthetic Redundancy.

    PubMed

    Escalera-Fanjul, Ximena; Campero-Basaldua, Carlos; Colón, Maritrini; González, James; Márquez, Dariel; González, Alicia

    2017-01-01

    Gene duplication is one of the major evolutionary mechanisms providing raw material for the generation of genes with new or modified functions. The yeast Saccharomyces cerevisiae originated after an allopolyploidization event, which involved mating between two different ancestral yeast species. ScALT1 and ScALT2 codify proteins with 65% identity, which were proposed to be paralogous alanine transaminases. Further analysis of their physiological role showed that while ScALT1 encodes an alanine transaminase which constitutes the main pathway for alanine biosynthesis and the sole pathway for alanine catabolism, ScAlt2 does not display alanine transaminase activity and is not involved in alanine metabolism. Moreover, phylogenetic studies have suggested that ScALT1 and ScALT2 come from each one of the two parental strains which gave rise to the ancestral hybrid. The present work has been aimed to the understanding of the properties of the ancestral type Lacchancea kluyveri LkALT1 and Kluyveromyces lactis KlALT1, alanine transaminases in order to better understand the ScALT1 and ScALT2 evolutionary history. These ancestral -type species were chosen since they harbor ALT1 genes, which are related to ScALT2. Presented results show that, although LkALT1 and KlALT1 constitute ScALT1 orthologous genes, encoding alanine transaminases, both yeasts display LkAlt1 and KlAlt1 independent alanine transaminase activity and additional unidentified alanine biosynthetic and catabolic pathway(s). Furthermore, phenotypic analysis of null mutants uncovered the fact that KlAlt1 and LkAlt1 have an additional role, not related to alanine metabolism but is necessary to achieve wild type growth rate. Our study shows that the ancestral alanine transaminase function has been retained by the ScALT1 encoded enzyme, which has specialized its catabolic character, while losing the alanine independent role observed in the ancestral type enzymes. The fact that ScAlt2 conserves 64% identity with LkAlt1

  15. A systems biology approach to understanding elevated serum alanine transaminase levels in a clinical trial with ximelagatran.

    PubMed

    Andersson, Ulf; Lindberg, Johan; Wang, Shunghuang; Balasubramanian, Raji; Marcusson-Ståhl, Maritha; Hannula, Mira; Zeng, Chenhui; Juhasz, Peter J; Kolmert, Johan; Bäckström, Jonas; Nord, Lars; Nilsson, Kerstin; Martin, Steve; Glinghammar, Björn; Cederbrant, Karin; Schuppe-Koistinen, Ina

    2009-12-01

    Ximelagatran was developed for the prevention and treatment of thromboembolic conditions. However, in long-term clinical trials with ximelagatran, the liver injury marker, alanine aminotransferase (ALT) increased in some patients. Analysis of plasma samples from 134 patients was carried out using proteomic and metabolomic platforms, with the aim of finding predictive biomarkers to explain the ALT elevation. Analytes that were changed after ximelagatran treatment included 3-hydroxybutyrate, pyruvic acid, CSF1R, Gc-globulin, L-glutamine, protein S and alanine, etc. Two of these analytes (pyruvic acid and CSF1R) were studied further in human cell cultures in vitro with ximelagatran. A systems biology approach applied in this study proved to be successful in generating new hypotheses for an unknown mechanism of toxicity.

  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. 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

  18. Factors underlying the association of body mass index with serum ALT in Chinese hypertensive adults without known hepatic diseases*

    PubMed Central

    Zhang, Yan; Qin, Xian-hui; Li, Jian-ping; Cui, Yi-min; Liu, Ze-yuan; Zhao, Zhi-gang; Ge, Jun-bo; Guan, De-ming; Hu, Jian; Wang, Yan-ni; Zhang, Fu-min; Xu, Xin; Xu, Xi-ping; Huo, Yong

    2013-01-01

    Objective: High body mass index (BMI) is considered as the most important risk factor for elevated serum alanine aminotransferase (ALT) concentration. This study examined an array of factors, including waist circumference (WC) and folate deficiency, which may mediate the association of BMI with serum ALT concentration in Chinese hypertensive adults without known hepatic diseases. Methods: A multicenter, cross-sectional study was carried out. A total of 378 patients with mild or moderate hypertension and without known hepatic diseases were recruited from five hospitals in Harbin, Shanghai, Beijing, Xi’an, and Nanjing. Results: Of the 360 hypertensive patients with complete data in our final analysis, 13.6% had high ALT concentrations (>40 IU/L). Factors including BMI, WC, triglyceride level, and folate concentration were associated with ALT concentration in univariate analysis. Consistently higher prevalence rates of elevated ALT were observed in subjects with lower folate concentrations (≥12 vs. <12 nmol/L, 9.9% vs. 17.8%, P=0.03), with higher BMI (≥28 vs. <28 kg/m2, 21.5% vs. 11.4%, P=0.02) or higher WC (≥90 vs. <90 cm, 18.5% vs. 10.0%, P=0.02). However, in multivariate analysis, the association between BMI and ALT concentration disappeared (P=0.802 in males and 0.369 in females), while WC in females (P<0.001) and folate concentration (P=0.036 in males and 0.044 in females) remained as significant predictors for ALT concentration. Conclusions: This multicenter study demonstrated that WC and low folate concentration were important factors underlying the association between BMI and ALT concentrations in Chinese hypertensive adults without known hepatic diseases. PMID:23897794

  19. 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.

  20. 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

  1. The influence of magnesium on the activity of some enzymes (AST, ALT, ALP) and lead content in some tissues.

    PubMed

    Todorovic, Tatjana; Vujanovic, Dragana

    2002-12-01

    Many authors in different studies have reported the antagonism between Mg and Pb. Our previous results suggested that oral Mg treatment have better effect on investigation biochemical parameters (protoporphyrins, aminolevulinic acid--ALA and d-aminolevulinic dehydratase ALA-D) used in evaluating Pb intoxication, then CaNa2EDTA, chelation agents, currently used in therapy of Pb intoxication. The toxic effect of Pb induced considerably modifies the activity of many other enzymes. In this work we have examined the influence of Mg (as alternative therapy of Pb poisoning) on enzymes activity--biochemical markers for general health conditions--aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in condition of lead intoxication. Many studies showed disturbances of activity ALT, AST and ALP. The aim of this study was to confirm positive effects of Mg intake in condition of such intoxication at the level on activity of investigated enzymes. The experiment was performed on 45 male Wister rats, divided in three groups. I--control group; II--group treated daily for 30 days with 100 mg Pb, per kg body weight and next 60 without Pb treatment (spontaneous detoxication); III group--the same treatment as II group for the first 30 days, but next 60 days rats were treated orally with 40 mg Mg/kg body weight. Activity of AST and ALT was significant increased in condition of Pb poisoning, but ALP activity was significant reduced. Influence of excessive oral Mg treatment was positive: decrease of AST activity and ALT activity, which was probably in correlation with significant elimination of Pb from liver and increase of ALT enzyme activity at the normal level.

  2. New pediatric percentiles of liver enzyme serum levels (ALT, AST, GGT): Effects of age, sex, BMI and pubertal stage.

    PubMed

    Bussler, Sarah; Vogel, Mandy; Pietzner, Diana; Harms, Kristian; Buzek, Theresa; Penke, Melanie; Händel, Norman; Körner, Antje; Baumann, Ulrich; Kiess, Wieland; Flemming, Gunter

    2017-09-19

    The present study aims to clarify the effects of sex, age, BMI and puberty on transaminase serum levels in children and adolescents and to provide new age- and sex-related percentiles for alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyltransferase (GGT). Venous blood and anthropometric data were collected from 4,126 cases. Excluded were cases of participants with potential hepatotoxic medication, with evidence of potential illness at the time of blood sampling and non-normal BMI (BMI < 10(th) or > 90(th) ). The resulting data (N = 3,131 cases) were used for the calculations of ALT, AST, and GGT percentiles. Age- and sex-related reference intervals were established by using an LMSP-type method. Serum levels of transaminases follow age-specific patterns and relate to the onset of puberty. This observation is more pronounced in girls than in boys. The ALT percentiles showed similar shaped patterns in both sexes. Multivariate regression confirmed significant effects of puberty and BMI-SDS (β = 2.21) on ALT. Surprisingly, AST serum levels were negatively influenced by age (β = -1.42) and BMI-SDS (β = -0.15). The GGT percentiles revealed significant sex-specific differences, correlated positively with age (β = 0.37) and showed significant association with BMI-SDS (β = 1.16). Current reference values of ALT, AST and GGT serum levels were calculated for children between 11 months and 16.0 years, using modern analytical and statistical methods. This study extends the current knowledge about transaminases by revealing influences of age, sex, BMI, and puberty on the serum concentrations of all three parameters and has for these parameters one of the largest sample sizes published so far. This article is protected by copyright. All rights reserved. © 2017 by the American Association for the Study of Liver Diseases.

  3. Weaning Induced Hepatic Oxidative Stress, Apoptosis, and Aminotransferases through MAPK Signaling Pathways in Piglets

    PubMed Central

    Luo, Zhen; Zhu, Wei; Guo, Qi; Luo, Wenli; Zhang, Jing; Xu, Weina

    2016-01-01

    This study investigated the effects of weaning on the hepatic redox status, apoptosis, function, and the mitogen-activated protein kinase (MAPK) signaling pathways during the first week after weaning in piglets. A total of 12 litters of piglets were weaned at d 21 and divided into the weaning group (WG) and the control group (CG). Six piglets from each group were slaughtered at d 0 (d 20, referred to weaning), d 1, d 4, and d 7 after weaning. Results showed that weaning significantly increased the concentrations of hepatic free radicals H2O2 and NO, malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), while significantly decreasing the inhibitory hydroxyl ability (IHA) and glutathione peroxidase (GSH-Px), and altered the level of superoxide dismutase (SOD). The apoptosis results showed that weaning increased the concentrations of caspase-3, caspase-8, caspase-9 and the ratio of Bax/Bcl-2. In addition, aspartate aminotransferase transaminase (AST) and alanine aminotransferase (ALT) in liver homogenates increased after weaning. The phosphorylated JNK and ERK1/2 increased, while the activated p38 initially decreased and then increased. Our results suggested that weaning increased the hepatic oxidative stress and aminotransferases and initiated apoptosis, which may be related to the activated MAPK pathways in postweaning piglets. PMID:27807471

  4. HIF3A DNA Methylation Is Associated with Childhood Obesity and ALT

    PubMed Central

    Wang, Shuo; Song, Jieyun; Yang, Yide; Zhang, Yining; Wang, Haijun; Ma, Jun

    2015-01-01

    Gene polymorphisms associated so far with body mass index (BMI) can explain only 1.18–1.45% of observed variation in BMI. Recent studies suggest that epigenetic modifications, especially DNA methylation, could contribute to explain part of the missing heritability, and two epigenetic genome-wide analysis studies (EWAS) have reported that Hypoxia Inducible Factor 3 Alpha Subunit (HIF3A) methylation was associated with BMI or BMI change. We therefore assessed whether the HIF3A methylation is associated with obesity and other obesity-related phenotypes in Chinese children. The subjects included 110 severe obese cases aged 7–17y and 110 normal-weight controls matched by age and gender for measurement of blood DNA methylation levels at the HIF3A gene locus using the Sequenom’s MassARRAY system. We observed significantly higher methylation levels in obese children than in controls at positions 46801642 and 46801699 in HIF3A gene (P<0.05), and found positive associations between methylation and alanine aminotransferase (ALT) levels adjusted by gender, age and BMI at the position 46801699 (r = 0.226, P = 0.007). These results suggest that HIF3A DNA methylation is associated with childhood obesity, and has a BMI-independent association with ALT. The results provide evidence for identifying epigenetic factors of elivated ALT and may be useful for risk assessment and personalized medicine of liver diseases such as non-alcoholic fatty liver disease (NAFLD). PMID:26717317

  5. HIF3A DNA Methylation Is Associated with Childhood Obesity and ALT.

    PubMed

    Wang, Shuo; Song, Jieyun; Yang, Yide; Zhang, Yining; Wang, Haijun; Ma, Jun

    2015-01-01

    Gene polymorphisms associated so far with body mass index (BMI) can explain only 1.18-1.45% of observed variation in BMI. Recent studies suggest that epigenetic modifications, especially DNA methylation, could contribute to explain part of the missing heritability, and two epigenetic genome-wide analysis studies (EWAS) have reported that Hypoxia Inducible Factor 3 Alpha Subunit (HIF3A) methylation was associated with BMI or BMI change. We therefore assessed whether the HIF3A methylation is associated with obesity and other obesity-related phenotypes in Chinese children. The subjects included 110 severe obese cases aged 7-17y and 110 normal-weight controls matched by age and gender for measurement of blood DNA methylation levels at the HIF3A gene locus using the Sequenom's MassARRAY system. We observed significantly higher methylation levels in obese children than in controls at positions 46801642 and 46801699 in HIF3A gene (P<0.05), and found positive associations between methylation and alanine aminotransferase (ALT) levels adjusted by gender, age and BMI at the position 46801699 (r = 0.226, P = 0.007). These results suggest that HIF3A DNA methylation is associated with childhood obesity, and has a BMI-independent association with ALT. The results provide evidence for identifying epigenetic factors of elivated ALT and may be useful for risk assessment and personalized medicine of liver diseases such as non-alcoholic fatty liver disease (NAFLD).

  6. 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.

  7. 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

  8. [The effect of diet ratio of polyunsaturated fatty acids of omega-3 and omega-6 families on activity of aminotransferases and gamma-glutamyltransferase in rat blood serum].

    PubMed

    Ketsa, O V; Marchenko, M M

    2014-01-01

    The effect of diet fat compositions with various ratio of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) on alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT) activities in blood serum of 45 white mongrel rats weighing 90-110 g (9 animals in group) has been investigated. Fat components in the semi-synthetic diet, compiled on the basis of AIN-93 diet, and sources of omega-6 and omega-3 PUFA were presented by sunflower oil, soybean oil and fish oil. It has been shown that four-week inclusion of linoleic acid (LA) and alpha-linolenic acid (alpha-LNA) in a ratio of 7:1 into the diet (soybean oil) as well as use of only omega-6 PUFA (sunflower oil) has lead to an increase in the activity of ALT and GGT in rat blood serum compared to control animals treated with the complex of linolenic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid through the mixture of sunflower oil and fish oil (9:1) with the ratio of omega-6 and omega-3 PUFA 7:1. Along with this, the AST:ALT ratio (de Ritis ratio) was lower (p < 0.05) as compared with the control group of rat, amounting respectively 0.92 +/- 0.08 and 0.79 +/- 0.12 vs 1.26 +/- 0.10. The use of high doses of omega-3 fatty acids (600 mg EPA and 400 mg DHA per kg of animal weight per day coming through fish oil) did not affect the activity of ALT and GGT, but increased AST serum activity (0.47 +/- 0.04 micromoles/min per mg protein) and the de Ritis ratio (2.53 +/- 0.23). The diet deprived with fat increased enzyme activity of ALT, AST and GGT in rat blood serum.

  9. 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

  10. 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.

  11. [Relationship of visceral adiposity index with serum aminotransferase and nonalcoholic fatty liver disease in patients with sleep apnea].

    PubMed

    Qi, Jiachao; Lin, Qichang; Lin, Xin; Chen, Xiao

    2015-11-10

    To evaluate the relationship of visceral adiposity index (VAI) with serum aminotransferase levels and incidence of nonalcoholic fatty liver disease (NAFLD) in patients with sleep apnea (SA). Between January 2011 and December 2014, participants who were referred from Fujian Provincial Sleep-disordered Breathing (SDB) Clinic Center with repeated snoring or a clinical suspicion of SDB were recruited. All individuals underwent polysomnography (PSG) testing and an abdominal ultrasonography scan during this period. They were classified into four groups by apnea-hypopnea index (AHI), non-SA group, mild, moderate and severe group (AHI<5/h, 5-<15/h, 15-<30/h, ≥30/h, respectively). The differences in SA-related parameters, serum aminotransferase and VAI were tested, and the correlations of VAI with indices of PSG and serum aminotransferase were analyzed using Spearman coefficient. Receiver operating characteristic (ROC) curve was conducted to obtain a cut-off value of VAI for predicting NAFLD. Afterwards, logistic regression was performed to analyze VAI's predictive ability regarding incidence of NAFLD in SDB patients. A total of 152 participants including 110 males and 42 females were analyzed, with mean age (51.1±11.3) years. There were 20 subjects in non-SA group, 31 in mild, 39 in moderate and 62 in severe group, with 92 NAFLD patients and 60 controls. No differences in sex, age, alkaline phosphatase were observed among groups according to AHI. However, body mass index, waist circumference, AHI, lowest oxygen saturation, oxygen desaturation index(ODI), VAI, alanine aminotransferase (ALT), aspartate aminotransferase, gamma glutamyltransferase (GGT) and incidence of NAFLD were significantly different among groups. Significant positive relations were observed between VAI and AHI (β=0.222, P=0.006), ODI (β=0.216, P=0.008), ALT (β=0.237, P=0.003), GGT (β=0.238, P=0.003). As shown in ROC curve, the cut-off point of VAI for predicting NAFLD was 1.59 in all individuals

  12. Predicting acute acetaminophen hepatotoxicity with acetaminophen-aminotransferase multiplication product and the Psi parameter.

    PubMed

    Chomchai, S; Chomchai, C

    2014-06-01

    Prediction of potential hepatotoxicity is important for individualizing therapy with N-acetylcysteine (NAC) in patients with acute acetaminophen overdose. Acetaminophen-aminotransferase multiplication product (APAP × AT) and the Psi Parameter (Psi) have been reported to be the predictors of acetaminophen hepatotoxicity. To determine the validity of APAP × AT and Psi in predicting hepatotoxicity secondary to acute acetaminophen overdose. We retrospectively reviewed acute acetaminophen overdose cases who were treated with NAC at Siriraj Hospital, Thailand during January 2004-June 2012. The patients' ages were 12 years or more. Initial acetaminophen concentration (mg/L) and aminotransferase (IU/L) were multiplied to obtain APAP × AT. Psi were derived from initial acetaminophen concentrations (mg/L) and lag time (hours) to NAC therapy. The cut-off values for APAP × AT and Psi were 1500 mg∙IU/L(2) and 5 mM∙h, respectively. Hepatotoxicity (defined as aspartate or alanine aminotransferase (ALT) greater than 1000 IU/L) was the outcome of interest. A total of 255 patients were included, 32 of whom developed hepatotoxicity. APAP × AT had sensitivity, specificity, and negative likelihood ratio of 90.6%, 62.8%, and 0.2, respectively. The sensitivity of Psi, specificity, and negative likelihood ratio were 96.9%, 91.5%, and 0.0, respectively. The areas under the curve of the receiver operating characteristic (ROC) curve for APAP × AT and Psi were 0.82 and 0.96, respectively, with a statistically significant difference between the two methods (p = 0.002). APAP × AT showed higher specificity (92.5%) in patients who presented 8-24 h after the overdose. Psi and APAP × AT are valid clinical tools in predicting hepatotoxicity secondary to acute acetaminophen overdose in adults. APAP × AT is useful in predicting a low likelihood of hepatotoxicity after standard NAC therapy among late-presenting patients.

  13. 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

  14. ALT/Space

    ERIC Educational Resources Information Center

    Rosenfeld, Malke, Ed.; Conarro, Ryan; Upshaw, Allison; Makol, Suzanne; Kelin, Daniel A., II; Redman, Jeff

    2013-01-01

    Stories in the "ALT/Space" section of each issue of "Teaching Artist Journal" illustrate and document a wide variety of topics surrounding the work of teaching artists while simultaneously revealing some larger truths about what it means to be an artist who teaches. This particular section focuses on the process and realities…

  15. Longitudinal association of obesity, metabolic syndrome and diabetes with risk of elevated aminotransferase levels in a cohort of Mexican health workers.

    PubMed

    Flores, Yvonne N; Auslander, Allyn; Crespi, Catherine M; Rodriguez, Michael; Zhang, Zuo-Feng; Durazo, Francisco; Salmerón, Jorge

    2016-05-01

    In Mexico, chronic liver disease have been increasingly found along with the rapidly growing prevalence of obesity, diabetes and metabolic syndrome (MS). We aimed to investigate the longitudinal association between these three factors and risk of elevated alanine aminotransferase (ALT) levels (>40 U/L), a marker for liver damage, in a cohort of Mexican adults. Data were obtained from two separate waves of the Mexican Health Worker Cohort Study: Wave 1 (2004-2006) and Wave 2 (2011-2013). Unconditional logistic regression models were employed to determine the cross-sectional and longitudinal association between these risk factors and elevated ALT levels. The prevalence of elevated ALT was significantly higher among men, individuals aged under 60 years, those who were overweight or obese, diabetic, with MS or heavy/binge drinkers. The longitudinal results indicated that weight gain between waves that resulted in a change in body mass index, along with remaining overweight or obese, were significantly associated with an increased risk of elevated ALT levels. A significantly increased risk of developing elevated ALT was also observed among those who acquired diabetes or MS from Wave 1 to Wave 2. Weight gain and acquiring diabetes or MS are associated with a significant risk of having elevated ALT. These results, within the context of the rapid increase in global obesity rates, call urgently for programs to help to prevent chronic liver disease. © 2016 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  16. Hepatic ALT isoenzymes are elevated in gluconeogenic conditions including diabetes and suppressed by insulin at the protein level

    PubMed Central

    Qian, Kun; Zhong, Shao; Xie, Keming; Yu, Daozhan; Yang, Rongze; Gong, Da-Wei

    2015-01-01

    Alanine transaminase (ALT) plays an important role in gluconeogenesis by converting alanine into pyruvate for glucose production. Early studies have shown that ALT activities are upregulated in gluconeogenic conditions and may be implicated in the development of diabetes. Since ALT consists of two isoforms, ALT1 and ALT2, with distinctive subcellular and tissue distributions, whether and how they are regulated are largely unknown. In this study, we found that both ALT isoforms in the liver were increased in diabetic GK rats and during fasting. However in ob/ob mice, only ALT2, but not ALT1, protein levels were elevated and the increase of ALT2 is correlated with that of ALT activity. We further demonstrated that, in vitro, both ALT1 and ALT2 were induced by glucocorticoid dexamethasone but suppressed by insulin in Fao hepatoma cells. Finally, we showed that the over-expression of ALT1 and ALT2 in Fao cells directly increased glucose output. Correctively, we have revealed the similarity and difference in the regulation of ALT isoforms in gluconeogenic conditions at the protein level, supporting that ALT isoenzymes play an important role in glucose metabolism and may be implicated the development of insulin resistance and diabetes. PMID:25865565

  17. Hepatic (Liver) Function Panel

    MedlinePlus

    ... related side effects. The hepatic function panel evaluates: Alanine aminotransferase (ALT). This enzyme, found in the liver, ... MORE ON THIS TOPIC Mononucleosis Hepatitis Blood Test: Alanine Aminotransferase (ALT, or SGPT) Blood Test: Aspartate Aminotransferase ( ...

  18. Protein retention and liver aminotransferase activities in Atlantic salmon fed diets containing different energy sources

    USGS Publications Warehouse

    Fynn-Aikins, K.; Hughes, S.G.; Vandenberg, G.W.

    1995-01-01

    Atlantic salmon (Salmo salar) fingerlings (14.4 g) were fed diets containing either glucose, dextrin, raw corn starch and lipid, or a high protein U.S. Fish and Wildlife Service open-formula diet (ASD2-30) for 12 weeks. Significant differences in weight gain and feed: gain ratio were not observed among salmon fed the diets containing glucose, dextrin or ASD2-30. Diets containing dextrin and glucose supported greater protein retention and reduction in alanine aminotransferase activity than the other diets. Activity of aspartate aminotransferase was not affected by the dietary treatment. Protein retention correlated highly with alanine aminotransferase activity.

  19. [Association between occupational stress and aminotransferase activity in patients with metabolic syndrome].

    PubMed

    Zhao, H; Song, L; Qiang, Y; Liu, H R; Qiu, F Y; Li, X Z; Song, H

    2016-12-20

    Objective: To investigate the association between occupational stress and activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in patients with metabolic syndrome. Methods: A case-control study was performed. According to inclusion and exclusion criteria, among the staff members of enterprises and public institutions aged 20~60 years who underwent physical examination in The Affiliated Hospital of Ningxia Medical University and The People's Hospital of Wuzhong from October 2011 to October 2012, 622 patients with metabolic syndrome who did not have a blood relationship with each other were enrolled as case group, and 600 healthy staff members who also did not have a blood relationshipwith each otherwere enrolled as control group. Questionnaire investigation, chronic occupational stress investigation, physical examination, and laboratory tests were performed for all subjects. Results: Compared with the control group, the case group had significantly higher serum levels and abnormal rates of AST and ALT (t=-4.338 and-5.485, χ(2)=11.168 and 34.302, all P<0.05) . There were no significantdifferences in the serum level and abnormal rate of AST between the subgroups with different occupational stresses in both groups (F=2.192 and 2.567, χ(2)=2.694 and 5.402, all P>0.05) , but there were significant differencesbetween the subgroups in all subjects (F=5.005, χ(2)=6.398, all P<0.05) . There were no significant differences in the serum level and abnormal rate of ALT between thesubgroups with different occupational stresses in the case group, the control group, and all subjects (F=0.845, 0.450, and 1.416, χ(2)=2.564, 1.344, and 3.147, all P>0.05) . The partial correlation analysis showed that the total score of occupational stress was positively correlated withthe serum level of AST (r=0.071, P<0.05) and was not correlated with the serum level of ALT (r=-0.044, P>0.05) , and that the serum level of AST was positively correlated with that of ALT

  20. Predictive value of serum ALT and T-cell receptor beta variable chain for HBeAg seroconversion in chronic hepatitis B patients during tenofovir treatment

    PubMed Central

    Yang, Jiezuan; Yan, Dong; Guo, Renyong; Chen, Jiajia; Li, Yongtao; Fan, Jun; Fu, Xuyan; Yao, Xinsheng; Diao, Hongyan; Li, Lanjuan

    2017-01-01

    Abstract Effective antiviral therapy plays a key role in slowing the progression of chronic hepatitis B (CHB). Identification of serum indices, including hepatitis B e antigen (HBeAg) expression and seroconversion, will facilitate evaluation of the efficacy of antiviral therapy in HBeAg-positive CHB patients. The biochemical, serological, virological parameters, and the frequency of circulating CD4+CD25+ regulatory T cell (Treg) in 32 patients were measured at baseline and every 12 weeks during 96 weeks of tenofovir disoproxil fumarate (TDF) treatment. The relationship between the hepatitis B virus (HBV) deoxyribonucleic acid (DNA) and Treg and alanine aminotransferase (ALT) levels was analyzed, respectively. The molecular profiles of T-cell receptor beta variable chain (TRBV) were determined using gene melting spectral pattern. For the seroconverted 12 patients, ALT declined to normal levels by week 24 and remained at this level in subsequent treatment; moreover, the predictive cutoff value of ALT for HBeAg seroconversion (SC) was 41.5 U/L at week 24. The positive correlation between HBV DNA and Treg and ALT was significant in SC patients, but not in non-SC patients. Six TRBV families (BV3, BV11, BV12, BV14, BV20, and BV24) were predominantly expressed in SC patients at baseline. The decline of ALT could be used to predict HBeAg seroconversion for CHB patients during TDF treatment. In addition, the profile of Tregs and TRBVs may be associated with HBeAg seroconversion and could also be a potential indicator for predicting HBeAg SC and treatment outcome for CHB patients. PMID:28272219

  1. Predictive value of serum ALT and T-cell receptor beta variable chain for HBeAg seroconversion in chronic hepatitis B patients during tenofovir treatment.

    PubMed

    Yang, Jiezuan; Yan, Dong; Guo, Renyong; Chen, Jiajia; Li, Yongtao; Fan, Jun; Fu, Xuyan; Yao, Xinsheng; Diao, Hongyan; Li, Lanjuan

    2017-03-01

    Effective antiviral therapy plays a key role in slowing the progression of chronic hepatitis B (CHB). Identification of serum indices, including hepatitis B e antigen (HBeAg) expression and seroconversion, will facilitate evaluation of the efficacy of antiviral therapy in HBeAg-positive CHB patients. The biochemical, serological, virological parameters, and the frequency of circulating CD4CD25 regulatory T cell (Treg) in 32 patients were measured at baseline and every 12 weeks during 96 weeks of tenofovir disoproxil fumarate (TDF) treatment. The relationship between the hepatitis B virus (HBV) deoxyribonucleic acid (DNA) and Treg and alanine aminotransferase (ALT) levels was analyzed, respectively. The molecular profiles of T-cell receptor beta variable chain (TRBV) were determined using gene melting spectral pattern. For the seroconverted 12 patients, ALT declined to normal levels by week 24 and remained at this level in subsequent treatment; moreover, the predictive cutoff value of ALT for HBeAg seroconversion (SC) was 41.5 U/L at week 24. The positive correlation between HBV DNA and Treg and ALT was significant in SC patients, but not in non-SC patients. Six TRBV families (BV3, BV11, BV12, BV14, BV20, and BV24) were predominantly expressed in SC patients at baseline. The decline of ALT could be used to predict HBeAg seroconversion for CHB patients during TDF treatment. In addition, the profile of Tregs and TRBVs may be associated with HBeAg seroconversion and could also be a potential indicator for predicting HBeAg SC and treatment outcome for CHB patients.

  2. Aerodynamic challenges of ALT

    NASA Technical Reports Server (NTRS)

    Hooks, I.; Homan, D.; Romere, P. O.

    1985-01-01

    The approach and landing test (ALT) of the Space Shuttle Orbiter presented a number of unique challenges in the area of aerodynamics. The purpose of the ALT program was both to confirm the use of the Boeing 747 as a transport vehicle for ferrying the Orbiter across the country and to demonstrate the flight characteristics of the Orbiter in its approach and landing phase. Concerns for structural fatigue and performance dictated a tailcone be attached to the Orbiter for ferry and for the initial landing tests. The Orbiter with a tailcone attached presented additional challenges to the normal aft sting concept of wind tunnel testing. The landing tests required that the Orbiter be separated from the 747 at approximately 20,000 feet using aerodynamic forces to fly the vehicles apart. The concept required a complex test program to determine the relative effects of the two vehicles on each other. Also of concern, and tested, was the vortex wake created by the 747 and the means for the Orbiter to avoid it following separation.

  3. Studies on some kinetic parameters of aminotransferases in tissues of the snail, Pila globosa (Swainson) during malathion intoxication.

    PubMed

    Sahib, I K; Rao, K R

    1988-01-01

    The aspartate and alanine aminotransferases in the tissues of the snail, Pila globosa showed high catalytic potentials (low Km and high Vmax) during malathion exposure in vivo. In vitro addition of different concentrations of malathion did not influence aminotransferase activity. The results are discussed in relation to the regulative influence of the intracellular environment of the cell.

  4. Predictors of treatment efficacy and ALT non-normalization with sofosbuvir/ribavirin therapy for patients with hepatitis C virus genotype 2.

    PubMed

    Watanabe, Takao; Tokumoto, Yoshio; Joko, Kouji; Michitaka, Kojiro; Horiike, Norio; Tanaka, Yoshinori; Tada, Fujimasa; Kisaka, Yoshiyasu; Nakanishi, Seiji; Nonaka, Takashi; Yamauchi, Kazuhiko; Hirooka, Masashi; Abe, Masanori; Hiasa, Yoichi

    2017-09-01

    The tolerability and efficacy of sofosbuvir and ribavirin in patients infected with hepatitis C virus (HCV) genotype 2 were investigated under actual clinical conditions. A total of 208 patients with chronic HCV genotype 2 infection were treated with sofosbuvir 400 mg and ribavirin (weight-based dosing) for 12 weeks. Treatment discontinuation and sustained virological response 12 (SVR12) were evaluated. Moreover, factors associated with SVR12, hemoglobin decreasing to less than 10 g/dL during treatment, and alanine aminotransferase (ALT) non-normalization after treatment were evaluated. In all patients, SVR12 responses were 96.1% (200/208). About 6 of 8 patients (3.8%) who did not achieve SVR12 were re-treatment patients, and eight patients who did not achieve SVR all had liver cirrhosis. Multivariate analysis also identified body mass index (OR = 0.79; P < 0.001), platelet count (OR = 0.88; P = 0.003), and estimated glomerular filtration rate (eGFR) (OR = 0.96; P = 0.007) as independent contributing factors associated with hemoglobin decreasing to less than 10 g/dL during treatment, and only Mac-2 Binding Protein Glycosylation isomer (M2BpGi) (OR = 2.46; P = 0.017) as an independent contributing factor associated with ALT non-normalization after treatment. Cirrhotic patients may have a relatively high rate of treatment failure. In patients whose M2BpGi levels are elevated, their ALT tended to not normalize after treatment completion. These patients who did not achieve normalization of ALT after sofosbuvir plus RBV treatment need more careful observation for emergence of hepatocellular carcinoma even after achievement of SVR. © 2017 Wiley Periodicals, Inc.

  5. 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

  6. Accuracy of the paracetamol-aminotransferase multiplication product to predict hepatotoxicity in modified-release paracetamol overdose.

    PubMed

    Wong, Anselm; Sivilotti, Marco L A; Graudins, Andis

    2017-06-01

    The paracetamol-aminotransferase multiplication product (APAP × ALT) is a risk predictor of hepatotoxicity that is somewhat independent of time and type of ingestion. However, its accuracy following ingestion of modified-release formulations is not known, as the product has been derived and validated after immediate-release paracetamol overdoses. The aim of this retrospective cohort study was to evaluate the accuracy of the multiplication product to predict hepatotoxicity in a cohort of patients with modified-release paracetamol overdose. We assessed all patients with modified-release paracetamol overdose presenting to our hospital network from October 2009 to July 2016. Ingestion of a modified-release formulation was identified by patient self-report or retrieval of the original container. Hepatotoxicity was defined as peak alanine aminotransferase ≥1000 IU/L, and acute liver injury (ALI) as a doubling of baseline ALT to more than 50 IU/L. Of 1989 paracetamol overdose presentations, we identified 73 modified-release paracetamol exposures treated with acetylcysteine. Five patients developed hepatotoxicity, including one who received acetylcysteine within eight hours of an acute ingestion. No patient with an initial multiplication product <10,000 mg/L × IU/L developed hepatotoxicity (sensitivity 100% [95%CI 48%, 100%], specificity 97% [90%, 100%]). Specificity fell to 54% (95%CI: 34, 59%) at a product cut-off point <1500 mg/L × IU/L. When calculated within eight hours of ingestion, mild elevations of the multiplication product fell quickly on repeat testing in patients without ALI or hepatotoxicity. In modified-release paracetamol overdose treated with acetylcysteine, the paracetamol-aminotransferase multiplication product demonstrated similar accuracy and temporal profile to previous reports involving mostly immediate-release formulations. Above a cut-point of 10,000 mg/L × IU/L, it was very strongly associated with the development

  7. Methionine Regeneration and Aspartate Aminotransferase in Parasitic Protozoa

    PubMed Central

    Berger, Louise C.; Wilson, Judith; Wood, Pamela; Berger, Bradley J.

    2001-01-01

    Aspartate aminotransferases have been cloned and expressed from Crithidia fasciculata, Trypanosoma brucei brucei, Giardia intestinalis, and Plasmodium falciparum and have been found to play a role in the final step of methionine regeneration from methylthioadenosine. All five enzymes contain sequence motifs consistent with membership in the Ia subfamily of aminotransferases; the crithidial and giardial enzymes and one trypanosomal enzyme were identified as cytoplasmic aspartate aminotransferases, and the second trypanosomal enzyme was identified as a mitochondrial aspartate aminotransferase. The plasmodial enzyme contained unique sequence substitutions and appears to be highly divergent from the existing members of the Ia subfamily. In addition, the P. falciparum enzyme is the first aminotransferase found to lack the invariant residue G197 (P. K. Mehta, T. I. Hale, and P. Christen, Eur. J. Biochem. 214:549–561, 1993), a feature shared by sequences discovered in P. vivax and P. berghei. All five enzymes were able to catalyze aspartate-ketoglutarate, tyrosine-ketoglutarate, and amino acid-ketomethiobutyrate aminotransfer reactions. In the latter, glutamate, phenylalanine, tyrosine, tryptophan, and histidine were all found to be effective amino donors. The crithidial and trypanosomal cytosolic aminotransferases were also able to catalyze alanine-ketoglutarate and glutamine-ketoglutarate aminotransfer reactions and, in common with the giardial aminotransferase, were able to catalyze the leucine-ketomethiobutyrate aminotransfer reaction. In all cases, the kinetic constants were broadly similar, with the exception of that of the plasmodial enzyme, which catalyzed the transamination of ketomethiobutyrate significantly more slowly than aspartate-ketoglutarate aminotransfer. This result obtained with the recombinant P. falciparum aminotransferase parallels the results seen for total ketomethiobutyrate transamination in malarial homogenates; activity in the latter was much

  8. ASA (ALT) Design, Develop, Deliver, Dominate

    DTIC Science & Technology

    2010-01-01

    Technology (ASA(ALT)) and the Principal Military Deputy to the ASA(ALT) ASA(ALT) Credo ASA(ALT) Overview Deputy for Acquisition and Systems...the people we serve and the communities we depend upon for support. ASA(ALT) Credo Assistant Secretary of the Army (Acquisition, Logistics and

  9. Aminotransferase levels in relation to short-term use of acetaminophen four grams daily in postoperative cardiothoracic patients in the intensive care unit.

    PubMed

    Ahlers, S J G M; Van Gulik, L; Van Dongen, E P A; Bruins, P; Tibboel, D; Knibbe, C A J

    2011-11-01

    A volunteer study suggested that taking paracetamol 4 g daily could result in elevated alanine aminotransferase plasma levels in a substantial proportion of healthy volunteers. The safety of this dose of paracetamol for acute postoperative pain remains controversial. This study aimed to examine the incidence of alanine aminotransferase elevations after short-term use of paracetamol 4 g daily, as part of the standard pain management protocol, for 93 consecutive patients after cardiothoracic surgery. Alanine aminotransferase levels and other liver function tests were measured preoperatively as baseline and once daily after surgery during the intensive care unit stay. Preoperative alanine aminotransferase levels of more than one time the upper limit of normal (ULN >40 U/l) was observed in 11% (n=10) of the patients but none of these baseline alanine aminotransferase levels exceeded three times the ULN (>3 x ULN). The average daily dose of paracetamol administered was 50 mg/kg (SD=16) after surgery. Postoperative alanine aminotransferase levels of >1 x ULN was observed in 17% (n=16), and 4% (n=4) exceeded >3 x ULN The other liver function tests of the latter four patients, including aspartate aminotransferase (range 173 to 5590 U/l), gamma-glutamyltransferase (range 56 to 103 U/l), lactate dehydrogenase (range 376 to 3518 U/l) and the International Normalised Ratio (range 2.0 to 6.6), were all abnormal. These four patients all had right ventricular failure or cardiogenic shock during the postoperative period which could explain the significant rises in alanine aminotransferase after surgery. In conclusion, the incidence of significant alanine aminotransferase elevations after using daily paracetamol as an analgesic agent for cardiac surgery, at a dose of 4 g per day, was low and mostly due to complications after surgery. Our results, albeit still very limited, provided some reassurance about the safety of paracetamol 4 g daily, as a supplementary analgesic agent for

  10. Low prevalence of chronic hepatitis C, but high prevalence of elevated aminotransferases in a cohort of 2026 patients referred for orthopaedic surgery in the eastern part of Germany.

    PubMed

    Wiegand, J; Kaiser, T; Lobstein, S; Brand, F; Wojan, M; Stölzel, U; Liebert, U G; Mössner, J; Tillmann, H L

    2006-01-01

    The prevalence of chronic hepatitis C in Germany is about 0.2 - 0.4 %. However, there seems to be regional differences between western and eastern states of the country. Thus, the present study analysed the prevalence of chronic hepatitis C in a cohort of orthopaedic patients in Thuringia. Tests for antibodies against hepatitis C virus (anti-HCV) were performed on serum samples of 2026 patients (1183 females, 843 males) admitted for orthopaedic surgery to a university hospital in Thuringia. If anti-HCV was positive, serum was tested for HCV-RNA by polymerase chain reaction (PCR). For the sake of anonymity only age and gender were reported in all patients. In 1465 cases, values of alanine (ALT) and aspartate (AST) aminotransferases were additionally available. The low HCV prevalence was confirmed in a second cohort of orthopaedic patients (n = 929, 599 females, 330 males) investigated at a university hospital in Saxonia. In the Thuringian cohort, anti-HCV was detectable in 12/2026 (0.6 %) individuals (10 females (0.85 %) and 2 males (0.24 %: p = 0.14 %). HCV-RNA was positive in 3/10 of anti-HCV positive females (0.15 % of the study cohort). HCV infection was already known in two cases. Anti-HCV positive patients seemed to be older than anti-HCV negative individuals (64.25 vs. 59.48 years; p = 0.17), as well as HCV-RNA positive cases compared to non-viraemic patients (66.3 vs. 63.6 years; p = 0.32). All HCV-RNA positive females had elevated ALT values. However, ALT and AST were also elevated in 18.2 % and 11.7 % of anti-HCV negative individuals. There was no significant difference between males and females (p = 0.32). In the Saxonian cohort none of 929 individuals were HCV positive. The prevalence of chronic hepatitis C is low in the investigated cohorts of orthopaedic patients in Thuringia and Saxonia. However, elevation of aminotransferases occurs surprisingly often. The reasons for elevated aminotransferases and a reliable analysis of the HCV prevalence in

  11. Suppression of Hepatocellular Carcinoma by Inhibition of Overexpressed Ornithine Aminotransferase.

    PubMed

    Zigmond, Ehud; Ben Ya'acov, Ami; Lee, Hyunbeom; Lichtenstein, Yoav; Shalev, Zvi; Smith, Yoav; Zolotarov, Lidya; Ziv, Ehud; Kalman, Rony; Le, Hoang V; Lu, Hejun; Silverman, Richard B; Ilan, Yaron

    2015-08-13

    Hepatocellular carcinoma is the second leading cause of cancer death worldwide. DNA microarray analysis identified the ornithine aminotransferase (OAT) gene as a prominent gene overexpressed in hepatocellular carcinoma (HCC) from Psammomys obesus. In vitro studies demonstrated inactivation of OAT by gabaculine (1), a neurotoxic natural product, which suppressed in vitro proliferation of two HCC cell lines. Alpha-fetoprotein (AFP) secretion, a biomarker for HCC, was suppressed by gabaculine in both cell lines, but not significantly. Because of the active site similarity between GABA aminotransferase (GABA-AT) and OAT, a library of 24 GABA-AT inhibitors was screened to identify a more selective inhibitor of OAT. (1S,3S)-3-Amino-4-(hexafluoropropan-2-ylidene)cyclopentane-1-carboxylic acid (2) was found to be an inactivator of OAT that only weakly inhibits GABA-AT, l-aspartate aminotransferase, and l-alanine aminotransferase. In vitro administration of 2 significantly suppressed AFP secretion in both Hep3B and HepG2 HCC cells; in vivo, 2 significantly suppressed AFP serum levels and tumor growth in HCC-harboring mice, even at 0.1 mg/kg. Overexpression of the OAT gene in HCC and the ability to block the growth of HCC by OAT inhibitors support the role of OAT as a potential therapeutic target to inhibit HCC growth. This is the first demonstration of suppression of HCC by an OAT inactivator.

  12. 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

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

    PubMed Central

    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

    2015-01-01

    Abstract 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

  14. ALT-114 and ALT-118 Alternative Approaches to NIST ...

    EPA Pesticide Factsheets

    In 2016, US EPA approved two separate alternatives (ALT 114 and ALT 118) for the preparation and certification of Hydrogen Chloride (HCl) and Mercury (Hg) cylinder reference gas standards that can serve as EPA Protocol gases where EPA Protocol are required, but unavailable. The alternatives were necessary due to the unavailability of NIST reference materials (SRM, NTRM, CRM or RGM) or VSL reference materials (VSL PRM or VSL CRM), reference materials identified in EPA’s Green Book as necessary to establish the traceability of EPA protocol gases. ALT 114 and ALT 118 provides a pathway for gas vendors to prepare and certify traceable gas cylinder standards for use in certifying Hg and HCl CEMS. In this presentation, EPA will describe the mechanics and requirements of the performance-based approach, provide an update on the availability of these gas standards and also discuss the potential for producing and certifying gas standards for other compounds using this approach. This presentation discusses the importance of NIST-traceable reference gases relative to regulatory source compliance emissions monitoring. Specifically this presentation discusses 2 new approaches for making necessary reference gases available in the absence of NIST reference materials. Moreover, these approaches provide an alternative approach to rapidly make available new reference gases for additional HAPS regulatory compliance emissions measurement and monitoring.

  15. Alanine water complexes.

    PubMed

    Vaquero, Vanesa; Sanz, M Eugenia; Peña, Isabel; Mata, Santiago; Cabezas, Carlos; López, Juan C; Alonso, José L

    2014-04-10

    Two complexes of alanine with water, alanine-(H2O)n (n = 1,2), have been generated by laser ablation of the amino acid in a supersonic jet containing water vapor and characterized using Fourier transform microwave spectroscopy. In the observed complexes, water molecules bind to the carboxylic group of alanine acting as both proton donors and acceptors. In alanine-H2O, the water molecule establishes two intermolecular hydrogen bonds forming a six-membered cycle, while in alanine-(H2O)2 the two water molecules establish three hydrogen bonds forming an eight-membered ring. In both complexes, the amino acid moiety is in its neutral form and shows the conformation observed to be the most stable for the bare molecule. The microsolvation study of alanine-(H2O)n (n = 1,2) can be taken as a first step toward understanding bulk properties at a microscopic level.

  16. Fine Particle Pollution, Alanine Transaminase, and Liver Cancer: A Taiwanese Prospective Cohort Study (REVEAL-HBV).

    PubMed

    Pan, Wen-Chi; Wu, Chih-Da; Chen, Mu-Jean; Huang, Yen-Tsung; Chen, Chien-Jen; Su, Huey-Jen; Yang, Hwai-I

    2016-03-01

    Exposure to fine particulate matter (PM2.5) may promote hepatic tumorgenesis through low-grade inflammation. Therefore, we assessed the association of long-term exposure levels of PM2.5 and subsequent risk of hepatocellular carcinoma (HCC) and investigated the mediation effect of inflammation as represented by alanine aminotransferase (ALT) on this association. Between 1991 and 1992, we recruited 23 820 participants in Taiwan with no history of HCC. Case patients of HCC were ascertained through computerized data linkage with the National Cancer Registry and death certification systems. Participants' exposures to PM2.5 were based on a four-year average retrieved from stationary monitoring sites. Cox proportional hazards models were used to assess the association between PM2.5 exposure and HCC incidence. Mediation effects of ALT on PM2.5-associated HCC incidence were estimated. A total of 464 HCC cases were newly diagnosed with a median follow-up of 16.9 years. Statistically significantly increasing trends between PM2.5 exposures and ALT were observed on the Main Island and Penghu Islets. The adjusted hazard ratio (HR) for HCC on the Penghu Islets was 1.22 (95% confidence interval [CI] = 1.02 to 1.47) per PM2.5 interquartile range (IQR) increment (0.73 µg/m(3)) exposure. We also found a positive association between PM2.5 exposure (per IQR increment, 13.1 µg/m(3)) and HCC incidence on the Main Island. Furthermore, ALT had a statistically significant mediation effect on PM2.5-associated HCC incidence (HR = 1.17, 95% CI = 1.02 to1.52 on the Main Island; HR = 1.04, 95% CI = 1.03 to 1.07 on the Penghu Islets) per PM2.5 IQR increment. Long-term PM2.5 exposure increased the risk for liver cancer, and chronic inflammation of the liver may underlie the pathogenesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. Probing alanine transaminase catalysis with hyperpolarized 13CD3-pyruvate

    PubMed Central

    Barb, A.W.; Hekmatyar, S.K.; Glushka, J.N.; Prestegard, J.H.

    2013-01-01

    Hyperpolarized metabolites offer a tremendous sensitivity advantage (>104 fold) when measuring flux and enzyme activity in living tissues by magnetic resonance methods. These sensitivity gains can also be applied to mechanistic studies that impose time and metabolite concentration limitations. Here we explore the use of hyperpolarization by dissolution dynamic nuclear polarization (DNP) in mechanistic studies of alanine transaminase (ALT), a well-established biomarker of liver disease and cancer that converts pyruvate to alanine using glutamate as a nitrogen donor. A specific deuterated, 13C-enriched analog of pyruvic acid, 13C3D3-pyruvic acid, is demonstrated to have advantages in terms of detection by both direct 13C observation and indirect observation through methyl protons introduced by ALT-catalyzed H–D exchange. Exchange on injecting hyperpolarized 13C3D3-pyruvate into ALT dissolved in buffered 1H2O, combined with an experimental approach to measure proton incorporation, provided information on mechanistic details of transaminase action on a 1.5 s timescale. ALT introduced, on average, 0.8 new protons into the methyl group of the alanine produced, indicating the presence of an off-pathway enamine intermediate. The opportunities for exploiting mechanism-dependent molecular signatures as well as indirect detection of hyperpolarized 13C3-pyruvate and products in imaging applications are discussed. PMID:23357427

  18. The effectiveness of fermented turmeric powder in subjects with elevated alanine transaminase levels: a randomised controlled study

    PubMed Central

    2013-01-01

    Background Previous animal studies have shown that Curcuma longa (turmeric) improves liver function. Turmeric may thus be a promising ingredient in functional foods aimed at improving liver function. The purpose of the study is to investigate the hepatoprotective effect of fermented turmeric powder (FTP) on liver function in subjects with elevated alanine transaminase (ALT) levels. Methods A randomised, double-blind, placebo-controlled trial was conducted between November 2010 and April 2012 at the clinical trial center for functional foods of the Chonbuk National University Hospital. The trial included 60 subjects, 20 years old and above, who were diagnosed mild to moderate elevated ALT levels between 40 IU/L and 200 IU/L. Sixty subjects were randomised to receive FTP 3.0 g per day or placebo 3.0 g per day for 12 weeks. The treatment group received two capsules of FTP three times a day after meals, for 12 weeks. The primary efficacy endpoint was change in the ALT levels in the two groups. The secondary efficacy endpoints included its effect on aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), total bilirubin (TB), and lipid profiles. Safety was assessed throughout the study using ongoing laboratory tests. Adverse events (AEs) were also recorded. Results Sixty subjects were randomised in the study (30 into the FTP group, 30 into the placebo group), and among them, twelve subjects were excluded from the analysis for protocol violation, adverse events or consent withdrawal. The two groups did not differ in baseline characteristics. After 12 weeks of treatment, 48 subjects were evaluated. Of the 48 subjects, 26 randomly received FTP capsules and 22 received placebo. The FTP group showed a significant reduction in ALT levels after 12 weeks of treatment compared with the placebo group (p = 0.019). There was also observed that the serum AST levels were significantly reduce in the FTP group than placebo group (p = 0.02). The GGT levels

  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. 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.

  1. Faraday diagnostics for ALT-3

    SciTech Connect

    Oro, David M; Tabaka, Leonard J

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the ALT-3 experiment.

  2. An innovative alt-alt telescope for small observatories and amateur astronomers

    NASA Astrophysics Data System (ADS)

    Riva, M.; Basso, S.; Canestrari, R.; Conconi, P.; Fugazza, D.; Ghigo, M.; Landoni, M.; Pareschi, G.; Spanó, P.; Tomelleri, R.; Zerbi, F. M.

    2012-09-01

    This paper want to show an innovative amateur oriented telescope with an unconventional alt-alt conguration. The goal is to make a telescope with good optical quality reducing production costs by adopting a gimbal based mounting to develop an alt-alt conguration suitable for a telescope. Reduce costs while preserving the optical quality is a necessary condition to allow small groups of amateur astronomers, schools and cultural clubs, with reduced economic resources, to acquire an astronomical instrument that encourages learning and advancing astrophysical knowledge. This unconventional mechanism for the realization of a telescope alt-alt provides signicant advantages. The traditional rotary motors coupled with expensive precision bearings are replaced with two simple linear actuators coupled to a properly preloaded gimbal joint and the cell becomes the primary structure of the telescope. A second advantage would be secured by mechanical simplicity evident in the easy portability of the instrument. The frame alt-alt has some limitations on the horizon pointing but does not show the zenith blind spot of the alt-az mount. A dedicated alt-alt pointing and tracking model is under development to be compatible with commercial telescope softwares and with the proposed new mounting.

  3. Porcine alanine transaminase after liver allo-and xenotransplantation

    PubMed Central

    Ekser, Burcin; Gridelli, Bruno; Cooper, David K.C.

    2013-01-01

    Aspartate transaminase (AST) and alanine transaminase (ALT) are measured following liver transplantation as indicators of hepatocellular injury. During a series of orthotopic liver allo-and xenotransplants, we observed that there was an increase in AST in all cases. The anticipated concomitant rise in ALT did not occur when a wild-type (WT) pig was the source of the liver graft, but did occur when a baboon or a genetically engineered (α1,3-galactosyltransferase gene-knockout [GTKO]) pig was the source of the graft. We hypothesized that the cience of Galα1,3 Gal in GTKO pig livers may render pig hepatocytes similar to human and baboon hepatocytes in their response to hepatocellular injury. Reviewing the literature, after WT pig liver allotransplantation or xenotransplantation, in the majority of reports, although changes in AST were reported, no mention was made of changes in ALT, suggesting that there was no change in ALT. However, Ramirez et al. reported two cases of liver xenotransplants from hCD55 pigs, following which there were increases in both AST and ALT, suggesting that it is not simply the cience of expression of Galα1,3 Gal that is the cause. We acknowledge that our observation is based on a small number of experiments, but we believe it is worth recording. PMID:22360753

  4. Porcine alanine transaminase after liver allo-and xenotransplantation.

    PubMed

    Ekser, Burcin; Gridelli, Bruno; Cooper, David K C

    2012-01-01

    Aspartate transaminase (AST) and alanine transaminase (ALT) are measured following liver transplantation as indicators of hepatocellular injury. During a series of orthotopic liver allo-and xenotransplants, we observed that there was an increase in AST in all cases. The anticipated concomitant rise in ALT did not occur when a wild-type (WT) pig was the source of the liver graft, but did occur when a baboon or a genetically engineered (α1,3-galactosyltransferase gene-knockout [GTKO]) pig was the source of the graft. We hypothesized that the cience of Galα1,3Gal in GTKO pig livers may render pig hepatocytes similar to human and baboon hepatocytes in their response to hepatocellular injury. Reviewing the literature, after WT pig liver allotransplantation or xenotransplantation, in the majority of reports, although changes in AST were reported, no mention was made of changes in ALT, suggesting that there was no change in ALT. However, Ramirez et al. reported two cases of liver xenotransplants from hCD55 pigs, following which there were increases in both AST and ALT, suggesting that it is not simply the cience of expression of Galα1,3Gal that is the cause. We acknowledge that our observation is based on a small number of experiments, but we believe it is worth recording.

  5. Blood Test: Comprehensive Metabolic Panel (CMP)

    MedlinePlus

    ... a decrease in kidney function. Alkaline phosphatase (ALP) , alanine amino transferase (ALT) , aspartate amino transferase (AST) , and ... Test: Glucose Kidneys and Urinary Tract Blood Test: Alanine Aminotransferase (ALT, or SGPT) Blood Test: Basic Metabolic ...

  6. Prevalence of elevated ALT values, HBsAg, and anti-HCV in the primary care setting and evaluation of guideline defined hepatitis risk scenarios.

    PubMed

    Wolffram, Ingmar; Petroff, David; Bätz, Olaf; Jedrysiak, Katrin; Kramer, Jan; Tenckhoff, Hannelore; Berg, Thomas; Wiegand, Johannes

    2015-06-01

    Prevalence data for hepatitis B and C and an evaluation of a guideline based screening in the primary care setting are not yet available. We therefore implemented a hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus (HCV) screening and developed guideline based screening strategies. HBsAg, anti-HCV, and alanine aminotransferase (ALT) were included in a routine check-up together with a questionnaire covering 16 guideline adapted risk scenarios. Significant risk factors were identified by stepwise logistic regression. 51 private practices screened 21,008 patients. The HBsAg, anti-HCV, and HCV-RNA prevalence was 0.52%, 0.95%, and 0.43%, respectively. Infections were previously unknown in 85% and 65% of HBsAg and anti-HCV positive individuals, respectively. Sexual risk factors were under-reported, while the following scenarios were significantly associated with viral infections (Odds ratio [95% confidence interval]). HBV: Immigration (4.4 [2.9, 6.7]), infection in household (2.5 [1.2, 4.5]), male gender (1.6 [1.1, 2.4]). Male immigrants had a 2.1% HBsAg prevalence and 80% were unaware of the infection. HCV: IV drug use (384 [233, 644]), blood transfusion before 1992 (5.3 [3.5, 7.9]), immigration (2.4 [1.5, 3.6]). Presence of either one of the HBV related guideline defined risk scenarios or elevated ALT identified 82% of previously undiagnosed patients. Presence of one of the three significant HCV risk factors or elevated ALT levels diagnosed 83% of unknown HCV-RNA positive cases by screening only 26% of the population. Undiagnosed hepatitis B and C infections frequently exist in the primary care setting. Easy to apply guideline defined risk scenarios help to diagnose previously unknown infections. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  7. Markerless Mutagenesis in Methanococcus maripaludis Demonstrates Roles for Alanine Dehydrogenase, Alanine Racemase, and Alanine Permease

    PubMed Central

    Moore, Brian C.; Leigh, John A.

    2005-01-01

    Among the archaea, Methanococcus maripaludis has the unusual ability to use l- or d-alanine as a nitrogen source. To understand how this occurs, we tested the roles of three adjacent genes encoding homologs of alanine dehydrogenase, alanine racemase, and alanine permease. To produce mutations in these genes, we devised a method for markerless mutagenesis that builds on previously established genetic tools for M. maripaludis. The technique uses a negative selection strategy that takes advantage of the ability of the M. maripaludis hpt gene encoding hypoxanthine phosphoribosyltransferase to confer sensitivity to the base analog 8-azahypoxanthine. In addition, we developed a negative selection method to stably incorporate constructs into the genome at the site of the upt gene encoding uracil phosphoribosyltransferase. Mutants with in-frame deletion mutations in the genes for alanine dehydrogenase and alanine permease lost the ability to grow on either isomer of alanine, while a mutant with an in-frame deletion mutation in the gene for alanine racemase lost only the ability to grow on d-alanine. The wild-type gene for alanine dehydrogenase, incorporated into the upt site, complemented the alanine dehydrogenase mutation. Hence, the permease is required for the transport of either isomer, the dehydrogenase is specific for the l isomer, and the racemase converts the d isomer to the l isomer. Phylogenetic analysis indicated that all three genes had been acquired by lateral gene transfer from the low-moles-percent G+C gram-positive bacteria. PMID:15659675

  8. Clinicopathological features of choledocholithiasis patients with high aminotransferase levels without cholangitis

    PubMed Central

    Huh, Cheal Wung; Jang, Sung Ill; Lim, Beom Jin; Kim, Hee Wook; Kim, Jae Keun; Park, Jun Sung; Kim, Ja Kyung; Lee, Se Joon; Lee, Dong Ki

    2016-01-01

    Abstract Common bile duct (CBD) stones are generally associated with greater elevations of alkaline phosphatase and gamma-glutamyl transpeptidase levels than aspartate aminotransferase and alanine aminotransferase levels. However, some patients with CBD stones show markedly increased aminotransferase levels, sometimes leading to the misdiagnosis of liver disease. Therefore, the aim of this study was to investigate the clinicopathologic features of patients with CBD stones and high aminotransferase levels. This prospective cohort study included 882 patients diagnosed with CBD stones using endoscopic retrograde cholangiopancreatography (ERCP). Among these patients, 38 (4.3%) exhibited aminotransferase levels above 400 IU/L without cholangitis (gallstone hepatitis [GSH] group), and 116 (13.2%) exhibited normal aminotransferase levels (control group). We compared groups in terms of clinical features, laboratory test results, radiologic images, and ERCP findings such as CBD diameter, CBD stone diameter and number, and periampullary diverticulum. Liver biopsy was performed for patients in the GSH group. GSH patients were younger and more likely to have gallbladder stones than control patients, implying a higher incidence of gallbladder stone migration. Also, GSH patients experienced more severe, short-lasting abdominal pain. ERCP showed narrower CBDs in GSH patients than in control patients. Histological analysis of liver tissue from GSH patients showed no abnormalities except for mild inflammation. Compared with control patients, GSH patients were younger and showed more severe, short-lasting abdominal pain, which could be due to a sudden increase of CBD pressure resulting from the migration of gallstones through narrower CBDs. These clinical features could be helpful not only for the differential diagnosis of liver disease but also for investigating the underlying mechanisms of liver damage in obstructive jaundice. Moreover, we propose a new definition of

  9. 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.

  10. ALT-114 and ALT-118 Alternative Approaches to NIST-Traceable Reference Gases

    EPA Science Inventory

    In 2016, US EPA approved two separate alternatives (ALT 114 and ALT 118) for the preparation and certification of Hydrogen Chloride (HCl) and Mercury (Hg) cylinder reference gas standards that can serve as EPA Protocol gases where EPA Protocol are required, but unavailable. The a...

  11. 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

  12. Low ALT blood levels predict long-term all-cause mortality among adults. A historical prospective cohort study.

    PubMed

    Ramaty, E; Maor, E; Peltz-Sinvani, N; Brom, A; Grinfeld, A; Kivity, S; Segev, S; Sidi, Y; Kessler, T; Sela, B A; Segal, G

    2014-12-01

    Increased blood levels of alanine amino transferase (ALT, also known as SGPT; serum glutamic pyruvic transaminase) serve as a marker of liver injury by various mechanisms. Less is known about the clinical implications associated with low-normal ALT levels. Previous studies showed low ALT levels to be associated with poor long-term outcomes among elderlies, serving as a biomarker for increased incidence of frailty and subsequent risk of mortality. However, it has not been determined yet whether low-normal ALT values might be predictive of frailty and mortality in younger, middle-aged adults. We conducted a historical prospective cohort analysis. A total of 23,506 adults with ALT levels within the normal range, at the mean age of 48 ± 11 years, participating in an annual screening program for preventive medicine, were followed-up for a median period of 8.5 years during which 638 died. Low-normal ALT values (serum ALT activity <17IU/L) were found to be predictive for increased risk of all-cause mortality (HR=1.6; 95% CI 1.34-1.92; p<0.001). Statistically significant correlation was demonstrated even after applying a multifactorial model correction for age, gender, eGFR, low albumin, arterial hypertension, diabetes mellitus and ischemic heart disease. We suggest that low-normal ALT values may serve as an independent predictive marker for increased long-term mortality in middle-aged adults. Copyright © 2014 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  13. Posttranslational alanine trans-stimulation of zwitterionic amino acid transport systems in human intestinal Caco-2 cells.

    PubMed

    Pan, Ming; Souba, Wiley W; Wolfgang, Christopher L; Karinch, Anne M; Stevens, Bruce R

    2002-05-01

    Neutral dietary amino acids, such as alanine, are transported across the gut lumen by both Na(+)-dependent (System B) and Na(+)-independent (System L) carriers, but the nature of the acute phase of substrate-induced uptake is unknown. This study examined the effects of acute amino acid substrate exposure on the rapid modulation of apical membrane alanine transport in cultured human intestinal cells. System B and System L transport activity kinetics, as well as ATB(0) mRNA levels, were measured in confluent Caco-2 monolayers treated with various metabolic agents during short-term and extended time periods. Depleting the incubation medium of alanine attenuated both System B and System L uptake activities within 30 mins, with a complete return to baseline values within 3 h. Extracellular alanine added to depleted Caco-2 cells rapidly (within 5 min) increased alanine transport activities. Kinetic analysis showed that acute alanine exposure increased both K(m) and V(max) of each transport system, indicative of a trans-stimulation effect. Augmenting intracellular alanine levels using the cytosolic alanine aminotransferase inhibitor, aminooxyacetic acid, increased alanine uptake activity. Acute exposure to other substrates of Systems B and L also increased the uptake of alanine, while nonsubstrates did not affect alanine uptake. Cycloheximide or actinomycin did not affect substrate acute activation of System B, and the steady-state level of ATB(0) mRNA was not altered by amino acid exposure. Increasing alanine availability to intestinal cells, by either exogenous substrate exposure or inhibition of intracellular catabolism, acutely and reversibly increases apical membrane alanine transport activity via a posttranslation trans-stimulation mechanism.

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

    PubMed

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

    2013-04-01

    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.

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

    PubMed Central

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

    2013-01-01

    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. PMID:23519665

  16. ALT-3 target design and simulations

    SciTech Connect

    Peterson, Jeffrey H

    2011-01-12

    ALT-3 is an experiment being designed in collaboration between Russian VNIIEF scientists and LANL that aims to conduct high velocity material experiments to measure shock velocities and pressures near 1 TPa. The DEMG (Disck Explosive Magnetic Generator) is used to drive> 60MA currents to accelerate an aluminum liner to speeds in excess of 20 km/s. 1-D and 2-D simulations of the aluminum target are presented with information on the free surface velocity profile, the state of the target, and the shock velocity in the target. 2-D simulations are presented showing the different targets available as well as a scenario with a perturbed liner impacter.

  17. ALT-3 Target & CMU Version 4

    SciTech Connect

    Griego, Jeffrey R; Atchison, Walter L.; Holtkamp, David; Oro, David M.; Reinovsky, Robert E.; Rousculp, Christopher L.; Tabaka, Leonard J.

    2012-06-11

    The third Advance Liner Technology (ALT-3) experiment is the next in a long tradition of collaborations between LANL and RFNC/VNIIEF in high-explosive pulsed-power. Here a VNIIEF provided Disk Explosive Magnetic Generator (DEMG) will drive a LANL provided experimental load and diagnostic package. The objective of the experiment is to explore the use of a cylindrical liner-ontarget in tera-Pascal equation of state measurement. This presentation will discuss version 4 of the experimental target and central measuring unit (CMU) along with R & D already performed in fabrication of the target.

  18. ALT-I pump limiter experiments

    SciTech Connect

    Goebel, D.M.; Conn, R.W.; Campbell, G.A.; Leung, W.K.; Dippel, K.H.; Finken, K.H.; Wolf, G.H.; Thomas, G.J.; Pontau, A.E.; Hsu, W.

    1987-09-01

    Results from the ALT-I pump limiter experiments in TEXTOR are presented. ALT-I has demonstrated control of the plasma density in a high recycling tokamak by pumping up to 15% of the core efflux. The closed pump limiter designs with restricted entrance geometries to reduce the backflow of neutral gas to the plasma remove over 50% of the ion flux incident on the collection slot. Up to 80% of the entrance ion flux is removed when the edge electron temperature is less than 10 eV and plasma-neutral gas interactions are minimized inside the limiter. Results from a 3-D Monte Carlo neutral gas transport code agree closely with these experimental results. The compound curvature of the head is found to distribute the heat over the surface as predicted in the original designs. Impurity removal experiments demonstrate that significant helium exhaust can be achieved with a pump limiter. During ohmic heating in TEXTOR, the energy and particle confinement times are proportional to the line averaged core density. With ICRH auxiliary heating, tau/sub E/ follow L-mode scaling independent of particle removal by the pump limiter. Pump limiter operation does not directly modify the SOL plasma density and electron temperature, but controls the core plasma density by changing the global recycling at the boundary. The global particle confinement, the particle flux to the limiter, and the edge electron temperature follow the changes in the core density and auxiliary heating power. 25 refs.

  19. Molecular analysis of the role of two aromatic aminotransferases and a broad-specificity aspartate aminotransferase in the aromatic amino acid metabolism of Pyrococcus furiosus

    PubMed Central

    Ward, Donald E.; de Vos, William M.; van der Oost, John

    2002-01-01

    The genes encoding aromatic aminotransferase II (AroAT II) and aspartate aminotransferase (AspAT) from Pyrococcus furiosus have been identified, expressed in Escherichia coli and the recombinant proteins characterized. The AroAT II enzyme was specific for the transamination reaction of the aromatic amino acids, and uses α-ketoglutarate as the amino acceptor. Like the previously characterized AroAT I, AroAT II has highest efficiency for phenylalanine (kcat/Km = 923 s–1 mM–1). Northern blot analyses revealed that AroAT I was mainly expressed when tryptone was the primary carbon and energy source. Although the expression was significantly lower, a similar trend was observed for AroAT II. These observations suggest that both AroATs are involved in amino acid degradation. Although AspAT exhibited highest activity with aspartate and α-ketoglutarate (kcat ~105 s–1), it also showed significant activity with alanine, glutamate and the aromatic amino acids. With aspartate as the amino donor, AspAT catalyzed the amination of α-ketoglutarate, pyruvate and phenylpyruvate. No activity was detected with either branched-chain amino acids or α-keto acids. The AspAT gene (aspC) was expressed as a polycistronic message as part of the aro operon, with expression observed only when the aromatic amino acids were absent from the growth medium, indicating a role in the biosynthesis of the aromatic amino acids. PMID:15803651

  20. [Conformation of aspartate aminotransferase in crystals].

    PubMed

    Borisov, V V; Borisova, S N; Sosfenov, N I; Dikson, Kh BF

    1983-01-01

    X-ray study of chicken cytosolic aspartate aminotransferase revealed conformational changes in the protein of two kinds: (1) a shift of the small domain adjacent to substrate-binding area due to interaction of the protein with two carboxyl groups of substrate and (2) a change in inclination of the coenzyme plane due to replacement of C = N bond of the coenzyme with Lys-258 by C = N bond with a substrate. An asymmetry in subunit behaviour is observed in both cases: the domain is shifted in one subunit and the coenzyme is rotated in other. Substrate-binding properties of each subunit are strictly dependent on the protein conformation in substrate-binding area.

  1. 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

  2. Layout modification for library cell Alt-PSM composability

    NASA Astrophysics Data System (ADS)

    Cao, Ke; Hu, Jiang; Cheng, Mosong

    2004-05-01

    In sub-wavelength lithography, light field Alt-PSM (Alternating Phase Shifting Mask) is an essential technology for poly layer printability. In a standard cell based design, the problem of obtaining Alt-PSM compliance for an individual cell layout has been solved well [3]. However, placing Alt-PSM compliant cells together can not guarantee Alt-PSM compliance of the entire chip/block layout due to phase interactions among adjacent cells. A simple solution to this Alt-PSM composability problem is to wrap blank area around each cell, which is very inefficient on chip area usage. In this paper, we formulate the composability problem as a graph model and propose a polynomial time optimal algorithm to achieve Alt-PSM composability with the least impact on cell layout.

  3. Association between elevated aminotransferase levels and the metabolic syndrome in Northern Turkey.

    PubMed

    Yildirim, Beytullah; Ozugurlu, Fikret; Sahin, Semsettin; Ozyurt, Huseyin; Atis, Omer; Akbas, Ali; Akturk, Yeliz; Ozdemir, Metin; Sahin, Idris; Bulut, Yunus; Etikan, Ylker; Firat, M Murat

    2010-01-01

    Elevated aminotransferase levels(ATLs) are alert the physicians for liver-affecting disease and may reflect liver injury. We aimed to determine the prevalence of elevated ATLs and the association of elevated ATLs with the metabolic syndrome (MetS) in a northern province of Turkey. Elevated ATLs were evaluated among 1,095 individuals of the Tokat Prevalence Study which have been described in detail elsewhere. 1,095 participants had been selected by a simple random sampling method among 530,000 inhabitants in 70 (12 urban and 58 rural) areas in the province of Tokat which is located in the Black Sea Region of Turkey. The prevalence of elevated serum ALT, AST, and ALT and/or AST were found as 11%, 7.2%, and 13.3%, respectively. Increased BMI, fatty liver, and MetS were higher in our general population with elevated ATLs. After exclusion of individuals with hepatitis B or hepatitis C infection, 132 individuals with elevated ATLs (91 male and 41 female) were evaluated. MetS was found in 59 participants and its prevalence was markedly higher in females with elevated ATLs (p < 0.0001). When the males with elevated ATLs were evaluated, the ALT levels of the persons who have no risk of MetS (p =0.007) and the persons who have one risk of MetS (p = 0.001) were lower than the persons with MetS. Elevated ATLs are common and it's an important cause is MetS in Northern Turkey.

  4. 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.

  5. Conversion of cysteine to 3-mercaptopyruvic acid by bacterial aminotransferases.

    PubMed

    Andreeßen, Christina; Gerlt, Vanessa; Steinbüchel, Alexander

    2017-04-01

    3-Mercaptopyruvate (3MPy), a structural analog of 3-mercaptopropionic acid, is a precursor compound for biosynthesis of polythioesters in bacteria. The cost-effectiveness and sustainability of the whole process could be greatly improved by using the cysteine degradation pathway for an intracellular supply of 3MPy. Transamination of cysteine to its corresponding α-keto acid 3MPy is catalyzed by cysteine aminotransferases (CAT). However, CAT activity has so far not been described for bacterial aminotransferases (AT), and it was unknown whether they can be applied for the conversion of cysteine to 3MPy. In this study, we selected eight bacterial aminotransferases based on sequence homology to CAT of Rattus norvegicus (Got1). The aminotransferases included four aspartate aminotransferases (AATs) and four aromatic amino acid aminotransferases (ArATs) from Advenella mimigardefordensis DPN7, Escherichia coli MG1655, Shimwellia blattae ATCC 33430, Ralstonia eutropha H16 and Paracoccus denitrificans PD1222. For a more detailed characterization, all selected AAT or ArAT encoding genes were heterologously expressed in E. coli and purified. CAT activity was detected for all aminotransferases when a novel continuous coupled enzyme assay was applied. Kinetic studies revealed the highest catalytic efficiency of 5.1mM/s for AAT from A. mimigardefordensis. Formation of 3MPy from cysteine could additionally be verified by an optimized approach using derivatization of 3MPy with the Girard T reagent and liquid chromatography-mass spectrometry analyses.

  6. Functional analysis of all aminotransferase proteins inferred from the genome sequence of Corynebacterium glutamicum.

    PubMed

    Marienhagen, Jan; Kennerknecht, Nicole; Sahm, Hermann; Eggeling, Lothar

    2005-11-01

    Twenty putative aminotransferase (AT) proteins of Corynebacterium glutamicum, or rather pyridoxal-5'-phosphate (PLP)-dependent enzymes, were isolated and assayed among others with L-glutamate, L-aspartate, and L-alanine as amino donors and a number of 2-oxo-acids as amino acceptors. One outstanding AT identified is AlaT, which has a broad amino donor specificity utilizing (in the order of preference) L-glutamate > 2-aminobutyrate > L-aspartate with pyruvate as acceptor. Another AT is AvtA, which utilizes L-alanine to aminate 2-oxo-isovalerate, the L-valine precursor, and 2-oxo-butyrate. A second AT active with the L-valine precursor and that of the other two branched-chain amino acids, too, is IlvE, and both enzyme activities overlap partially in vivo, as demonstrated by the analysis of deletion mutants. Also identified was AroT, the aromatic AT, and this and IlvE were shown to have comparable activities with phenylpyruvate, thus demonstrating the relevance of both ATs for L-phenylalanine synthesis. We also assessed the activity of two PLP-containing cysteine desulfurases, supplying a persulfide intermediate. One of them is SufS, which assists in the sulfur transfer pathway for the Fe-S cluster assembly. Together with the identification of further ATs and the additional analysis of deletion mutants, this results in an overview of the ATs within an organism that may not have been achieved thus far.

  7. Similarities between cysteinesulphinate transaminase and aspartate aminotransferase.

    PubMed

    Recasens, M; Mandel, P

    1979-01-01

    A method for the purification of two cysteinesulphinate transaminases, A and B (EC 2.6.1), is described. These enzymes catalyse the conversion of cysteinesulphinic acid to beta-sulphinyl pyruvate. The final preparations are homogeneous by polyacrylamide gel electrophoresis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and isoelectrofocusing. The molecular weight of the subunits is 41 000 for cysteinesulphinate transaminase A and 43 400 for B. Both enzymes are unspecific, as L-asparate, L-glutamate and L-cysteic acid serve as substrates in addition to L-cysteinesulphinic acid. Cysteinesulphinate transaminase A has a Km of 9.8 mM for cysteinesulphinic acid and 0.25 mM for aspartic acid, whereas the B enzyme has a Km of 6.5 mM for cysteinesulphinic acid and 1.4 mM for aspartic acid. The Vmax values of the A and B enzymes are respectively 7.1 and 6.2 mmol h-1 mg-1 protein for aspartic acid and 45 and 9.3 mmol h-1 mg-1 protein for cysteinesulphinic acid. Both enzymes exhibit maximum activity at pH 8.6. A high specific activity is found in optimal conditions for these two transaminases, the pI values being 9.06 and 5.70 for cysteinesulphinate transaminase A and B respectively. These results have been compared with those already obtained for purified aspartate aminotransferase. Similarities in the pathways of taurine and gamma-aminobutyric acid (GABA) metabolism are discussed.

  8. 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

  9. 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.

  10. [Raman scattering study of DL-alanine].

    PubMed

    Gong, Yan; Wang, Wen-qing

    2006-01-01

    Studies of Raman vibration spectra are useful to obtaining information on biomolecular crystals. The cell dimensions of the L- and DL-alanine crystals are nearly identical, and both structures belong to the orthorhombic system, but the space group is P2(1) 2(1) 2(1) for the L-isomer, and Pna2(1) for the racemate crystal. The Raman spectrum of L-alanine has been measured by many authors. The present work is focusing on the Raman scattering study of DL-alanine powder. Based on the analysis of the differences between DL-alanine and L-alanine Raman spectra, the authors obtained indispensable information on hydrogen bond and the motion of the molecular conformation in alanine crystals.

  11. 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.

  12. 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.

  13. 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.

  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. Lack of association between TTV viral load and aminotransferase levels in patients with hepatitis C or non-B-C.

    PubMed

    Kato, H; Mizokami, M; Orito, E; Ohno, T; Hayashi, K; Nakano, T; Kato, T; Tanaka, Y; Sugauchi, F; Mukaide, M; Ueda, R

    2000-01-01

    TT virus (TTV) is a newly identified un-enveloped single-stranded DNA virus. Although TTV was initially thought to be a new hepatitis virus, it is still unclear whether it causes hepatitis. To clarify the natural history and pathogenesis of TTV infection, serial serum samples from patients with chronic hepatitis were analysed. TTV DNA was quantified by real-time detection polymerase chain reaction assay (RTD-PCR), which was adapted for TTV. Five patients with chronic hepatitis, 4 with hepatitis C and 1 with non-B-C, were studied. The study period ranged from 9 to 50 months. In 3 patients there were frequent increases in TTV DNA titres, but no concomitant elevation of the aminotransferase (ALT) levels. In 2 patients who were treated with interferon, the changes in TTV titres were not synchronized with those of the ALT levels. Thus, in cases of chronic hepatitis, no correlation was observed between the serum TTV DNA titres and the ALT levels.

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

    PubMed

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

    2015-08-03

    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.

  17. Prevalence of elevated alanine transaminase in Australia and its relationship to metabolic risk factors: A cross-sectional study of 9,447 people.

    PubMed

    Mahady, Suzanne E; Gale, Joanne; Macaskill, Petra; Craig, Jonathan C; George, Jacob

    2017-01-01

    Elevated alanine transaminase (ALT) is a strong predictor of metabolic syndrome, but there are few data from the Australian population. We aimed to determine the prevalence of elevated ALT and association with metabolic risk factors. In this cross-sectional study including adult participants (N = 9,447) from a nationwide, population-based survey, we assessed the prevalence of elevated ALT [defined as ≥ 40 IU/L (men) and ≥ 30 IU/L (women) as baseline, and ALT as ≥ 30 IU/L (men) and ≥ 19 IU/L (women) as lower threshold], distribution of metabolic risk factors, and independent predictors of elevated ALT in logistic regression models. Analyses were weighted to the population with population weights. Elevated ALT levels were found in 11.2% of the Australian population. People with elevated ALT were younger (43 vs 46 yrs) with more truncal adiposity (100 vs 91 cm), higher pro-atherogenic lipids and glucose and exercised less (120 vs 160 min per week, P < 0.05 for all analyses). Regression analyses indicated that younger age, male sex, diabetes, triglycerides, apolipoprotein B, and waist circumference were independent predictors of elevated ALT. The population attributable fraction of elevated ALT due to truncal obesity was estimated at 47%. These data demonstrate a high prevalence of elevated ALT in the general population that is closely associated with metabolic risk factors. Individuals with elevated ALT should be evaluated for co-existent metabolic disorders. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

  18. PNPLA3 I148M polymorphism is associated with elevated alanine transaminase levels in Mexican Indigenous and Mestizo populations.

    PubMed

    Larrieta-Carrasco, Elena; Acuña-Alonzo, Victor; Velázquez-Cruz, Rafael; Barquera-Lozano, Rodrigo; León-Mimila, Paola; Villamil-Ramírez, Hugo; Menjivar, Marta; Romero-Hidalgo, Sandra; Méndez-Sánchez, Nahúm; Cárdenas, Vanessa; Bañuelos-Moreno, Manuel; Flores, Yvonne N; Quiterio, Manuel; Salmerón, Jorge; Sánchez-Muñoz, Fausto; Villarreal-Molina, Teresa; Aguilar-Salinas, Carlos A; Canizales-Quinteros, Samuel

    2014-07-01

    The patatin like phospholipase domain-containing (PNPLA3) I148M variant is the strongest genetic factor associated with elevated alanine transaminase (ALT) levels in different populations, particularly in Hispanics who have the highest 148M risk allele frequency reported to date. It has been suggested that Indigenous ancestry is associated with higher ALT levels in Mexicans. The aim of the present study was to assess the frequency of the PNPLA3 148M risk allele in Mexican indigenous and Mestizo individuals, and to examine its association with serum ALT levels. The study included a total of 1624 Mexican individuals: 919 Indigenous subjects from five different native groups and 705 Mexican Mestizo individuals (141 cases with ALT levels ≥ 40 U/L and 564 controls with ALT <40 U/L). The I148M polymorphism was genotyped by TaqMan assays. The frequency of elevated ALT levels in Indigenous populations was 18.7%, and varied according to obesity status: 14.4% in normal weight, 19.9% in overweight and 24.5% in obese individuals. The Mexican indigenous populations showed the highest reported frequency of the PNPLA3 148M risk allele (mean 0.73). The M148M genotype was significantly associated with elevated ALT levels in indigenous individuals (OR = 3.15, 95 % CI 1.91-5.20; P = 7.1 × 10(-6)) and this association was confirmed in Mexican Mestizos (OR = 2.24, 95% CI 1.50-3.33; P = 8.1 × 10(-5)). This is the first study reporting the association between M148M genotype and elevated ALT levels in Indigenous Mexican populations. The 148M allele risk may be considered an important risk factor for liver damage in Mexican indigenous and Mestizo populations.

  19. Structural and Functional Characterization of PseC, an Aminotransferase Involved in the Biosynthesis of Pseudaminic Acid, an Essential Flagellar Modification in Helicobacter Pylori

    SciTech Connect

    Schoenhofen,I.; Lunin, V.; Julien, J.; Li, Y.; Ajamian, E.; Matte, A.; Cygler, M.; Brisson, J.; Aubry, A.; et al.

    2006-01-01

    Helicobacter pylori flagellin is heavily glycosylated with the novel sialic acid-like nonulosonate, pseudaminic acid (Pse). The glycosylation process is essential for assembly of functional flagellar filaments and consequent bacterial motility. As motility is a key virulence factor for this and other important pathogens, the Pse biosynthetic pathway offers potential for novel therapeutic targets. From recent NMR analyses, we determined that the conversion of UDP-a-D-GlcNAc to the central intermediate in the pathway, UDP-4-amino-4,6-dideoxy-{beta}-L-AltNAc, proceeds by formation of UDP-2-acetamido-2,6-dideoxy-{beta}-L-arabino-4-hexulose by the dehydratase/epimerase PseB (HP0840) followed with amino transfer by the aminotransferase, PseC (HP0366). The central role of PseC in the H. pylori Pse biosynthetic pathway prompted us to determine crystal structures of the native protein, its complexes with pyridoxal phosphate alone and in combination with the UDP-4-amino-4,6-dideoxy-{beta}-L-AltNAc product, the latter being converted to the external aldimine form in the enzyme's active site. In the binding site, the AltNAc sugar ring adopts a 4C1 chair conformation which is different from the predominant 1C4 form found in solution. The enzyme forms a homodimer where each monomer contributes to the active site, and these structures have permitted the identification of key residues involved in stabilization, and possibly catalysis, of the {beta}-L-arabino intermediate during the amino transfer reaction. The essential role of Lys183 in the catalytic event was confirmed by site-directed mutagenesis. This work presents for the first time a nucleotide-sugar aminotransferase co-crystallized with its natural ligand, and in conjunction with the recent functional characterization of this enzyme, will assist in elucidating the aminotransferase reaction mechanism within the Pse biosynthetic pathway.

  20. Stabilization of rat liver tyrosine aminotransferase by tetracycline.

    PubMed Central

    Hannah, R; Sahib, M K

    1975-01-01

    Rat liver tyrosine aminotransferase was purified 200-fold and an antiserum raised against it in rabbits. 2. Hepatic tyrosine aminotransferase activity was increased fourfold by tyrosine, twofold by tetracycline, 2.5-fold by cortisone 21-acetate and ninefold by a combination of tyrosine and cortisol administered intraperitoneally to rats. 3. Radioimmunoassay with 14C-labelled tyrosine aminotransferase, in conjunction with rabbit antiserum against the enzyme, revealed that cortisol stimulates the synthesis of the enzyme de novo, but that tetracycline has no such effect. 4. Incubation of rat liver homogenates with purified tyrosine aminotransferase in vitro leads to a rapid inactivation of the enzyme, which tetracycline partially inhibits. 5. The inactivation is brought about by intact lysosomes, and the addition of 10mM-cysteine increases the rate of enzyme inactivation, which is further markedly increased by 10mM-Mg2+ and 10mM-ATP. Here again tetracycline partially inhibits the decay rate, leading to the inference that the increase of tyrosine aminotransferase activity in vivo by tetracycline is brought about by the latter inhibiting the lysosomal catheptic action. PMID:2154

  1. Stabilization of rat liver tyrosine aminotransferase by tetracycline.

    PubMed

    Hannah, R; Sahib, M K

    1975-09-01

    Rat liver tyrosine aminotransferase was purified 200-fold and an antiserum raised against it in rabbits. 2. Hepatic tyrosine aminotransferase activity was increased fourfold by tyrosine, twofold by tetracycline, 2.5-fold by cortisone 21-acetate and ninefold by a combination of tyrosine and cortisol administered intraperitoneally to rats. 3. Radioimmunoassay with 14C-labelled tyrosine aminotransferase, in conjunction with rabbit antiserum against the enzyme, revealed that cortisol stimulates the synthesis of the enzyme de novo, but that tetracycline has no such effect. 4. Incubation of rat liver homogenates with purified tyrosine aminotransferase in vitro leads to a rapid inactivation of the enzyme, which tetracycline partially inhibits. 5. The inactivation is brought about by intact lysosomes, and the addition of 10mM-cysteine increases the rate of enzyme inactivation, which is further markedly increased by 10mM-Mg2+ and 10mM-ATP. Here again tetracycline partially inhibits the decay rate, leading to the inference that the increase of tyrosine aminotransferase activity in vivo by tetracycline is brought about by the latter inhibiting the lysosomal catheptic action.

  2. Alanine increases blood pressure during hypotension

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Maher, T. J.; Wurtman, R. J.

    1990-01-01

    The effect of L-alanine administration on blood pressure (BP) during haemorrhagic shock was investigated using anesthetized rats whose left carotid arteries were cannulated for BP measurement, blood removal, and drug administration. It was found that L-alanine, in doses of 10, 25, 50, 100, and 200 mg/kg, increased the systolic BP of hypotensive rats by 38 to 80 percent (while 100 mg/kg pyruvate increased BP by only 9.4 mmhg, not significantly different from saline). The results suggest that L-alanine might influence cardiovascular function.

  3. Alanine increases blood pressure during hypotension

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Maher, T. J.; Wurtman, R. J.

    1990-01-01

    The effect of L-alanine administration on blood pressure (BP) during haemorrhagic shock was investigated using anesthetized rats whose left carotid arteries were cannulated for BP measurement, blood removal, and drug administration. It was found that L-alanine, in doses of 10, 25, 50, 100, and 200 mg/kg, increased the systolic BP of hypotensive rats by 38 to 80 percent (while 100 mg/kg pyruvate increased BP by only 9.4 mmhg, not significantly different from saline). The results suggest that L-alanine might influence cardiovascular function.

  4. Structure of putrescine aminotransferase from Escherichia coli provides insights into the substrate specificity among class III aminotransferases.

    PubMed

    Cha, Hyung Jin; Jeong, Jae-Hee; Rojviriya, Catleya; Kim, Yeon-Gil

    2014-01-01

    YgjG is a putrescine aminotransferase enzyme that transfers amino groups from compounds with terminal primary amines to compounds with an aldehyde group using pyridoxal-5'-phosphate (PLP) as a cofactor. Previous biochemical data show that the enzyme prefers primary diamines, such as putrescine, over ornithine as a substrate. To better understand the enzyme's substrate specificity, crystal structures of YgjG from Escherichia coli were determined at 2.3 and 2.1 Å resolutions for the free and putrescine-bound enzymes, respectively. Sequence and structural analyses revealed that YgjG forms a dimer that adopts a class III PLP-dependent aminotransferase fold. A structural comparison between YgjG and other class III aminotransferases revealed that their structures are similar. However, YgjG has an additional N-terminal helical structure that partially contributes to a dimeric interaction with the other subunit via a helix-helix interaction. Interestingly, the YgjG substrate-binding site entrance size and charge distribution are smaller and more hydrophobic than other class III aminotransferases, which suggest that YgjG has a unique substrate binding site that could accommodate primary aliphatic diamine substrates, including putrescine. The YgjG crystal structures provide structural clues to putrescine aminotransferase substrate specificity and binding.

  5. Production of Alanine by Fusarium moniliforme

    PubMed Central

    Carito, Sebastian L.; Pisano, Michael A.

    1966-01-01

    Fusarium moniliforme grown in a chemically defined medium in submerged culture accumulated amino acids extracellularly. Alanine and glutamic acid were present in greatest amounts, with traces of glycine, lysine, threonine, and valine detectable. Increasing the glucose and urea concentrations of the medium increased yields of alanine. Further increases in alanine production occurred with elevated levels of mineral salts in the medium, whereas the addition of a vitamin mixture proved to be inhibitory. Chemical changes resulting from the growth of F. moniliforme in the final fermentation medium disclosed maximal alanine production, mycelial weight, and glucose consumption after 72 hr of incubation at 28.5 C. Total soluble nitrogen, by contrast, was minimal at the same time period. The pH remained in the alkaline range throughout the fermentation. PMID:5914495

  6. METHANOGENS WITH PSEUDOMUREIN USE DIAMINOPIMELATE AMINOTRANSFERASE IN LYSINE BIOSYNTHESIS

    PubMed Central

    Graham, David E.; Huse, Holly K.

    2008-01-01

    Methanothermobacter thermautotrophicus uses lysine for both protein synthesis and cross-linking pseudomurein in its cell wall. A diaminopimelate aminotransferase enzyme from this methanogen (MTH0052) converts tetrahydrodipicolinate to L,L-diaminopimelate, a lysine precursor. This gene complemented an Escherichia coli diaminopimelate auxotrophy, and the purified protein catalyzed the transamination of diaminopimelate to tetrahydrodipicolinate. Phylogenetic analysis indicated this gene was recruited from anaerobic Gram-positive bacteria. These results expand the family of diaminopimelate aminotransferases to a diverse set of plant, bacterial and archaeal homologs. In contrast marine methanogens from the Methanococcales, which lack pseudomurein, appear to use a different diaminopimelate pathway for lysine biosynthesis. PMID:18371309

  7. The alanine racemase of Mycobacterium smegmatis is essential for growth in the absence of D-alanine.

    PubMed

    Milligan, Daniel L; Tran, Sieu L; Strych, Ulrich; Cook, Gregory M; Krause, Kurt L

    2007-11-01

    Alanine racemase, encoded by the gene alr, is an important enzyme in the synthesis of d-alanine for peptidoglycan biosynthesis. Strains of Mycobacterium smegmatis with a deletion mutation of the alr gene were found to require d-alanine for growth in both rich and minimal media. This indicates that alanine racemase is the only source of d-alanine for cell wall biosynthesis in M. smegmatis and confirms alanine racemase as a viable target gene for antimycobacterial drug development.

  8. ALT-II armor tile design for upgraded TEXTOR operation

    SciTech Connect

    Newberry, B.L.; McGrath, R.T.; Watson, R.D.; Kohlhaas, W.; Finken, K.H.; Noda, N.

    1994-08-01

    The upgrade of the TEXTOR tokamak at KFA Juelich was recently completed. This upgrade extended the TEXTOR pulse length from 5 seconds to 10 seconds. The auxiliary heating was increased to a total of 8.0 MW through a combination of neutral beam injection and radio frequency heating. Originally, the inertially cooled armor tiles of the full toroidal belt Advanced Limiter Test -- II (ALT-II) were designed for a 5-second operation with total heating of 6.0 MW. The upgrade of TEXTOR will increase the energy deposited per pulse onto the ALT-II by about 300%. Consequently, the graphite armor tiles for the ALT-II had to be redesigned to avoid excessively high graphite armor surface temperatures that would lead to unacceptable contamination of the plasma. This redesign took the form of two major changes in the ALT-II armor tile geometry. The first design change was an increase of the armor tile thermal mass, primarily by increasing the radial thickness of each tile from 17 mm to 20 mm. This increase in the radial tile dimension reduces the overall pumping efficiency of the ALT-II pump limiter by about 30%. The reduction in exhaust efficiency is unfortunate, but could be avoided only by active cooling of the ALT-II armor tiles. The active cooling option was too complicated and expensive to be considered at this time. The second design change involved redefining the plasma facing surface of each armor tile in order to fully utilize the entire surface area. The incident charged particle heat flux was distributed uniformly over the armor tile surfaces by carefully matching the radial, poloidal and toroidal curvature of each tile to the plasma flow in the TEXTOR boundary layer. This geometry redefinition complicates the manufacturing of the armor tiles, but results in significant thermal performance gains. In addition to these geometry upgrades, several material options were analyzed and evaluated.

  9. ALT-II armor tile design for upgraded TEXTOR operation

    SciTech Connect

    Newberry, B.L.; McGrath, R.T.; Watson, R.D.

    1994-12-31

    The upgrade of the TEXTOR tokamak at KFA Julich will be completed in the spring of 1994. The upgrade will extend the TEXTOR pulse length from 5 seconds to 10 seconds. The auxiliary heating systems are also scheduled to be upgraded so that eventually a total of 8.0 MW auxiliary heating will be available through a combination of neutral beam injection and radio frequency heating. Originally, the inertially cooled armor tiles on the full toroidal belt Advanced Limiter Test - II (ALT-II) were designed for 5-second operation with a total heating power of 6.0 MW. The upgrade of TEXTOR will increase the energy deposited per pulse onto ALT-II by more than 300%. Consequently, the graphite armor tiles for ALT-II had to be redesigned in order to increase their thermal inertia and, thereby, avoid excessively high graphite armor surface temperatures that would lead to unacceptable contamination of the plasma. The armor tile thermal inertia had been increase primarily by expanding the radial thickness of the tiles from 17 mm to 20 mm. This increase in radial tile dimension will reduce the overall pumping efficiency of the ALT-II pump limiter by about 30%. The final armor tile design was a compromise between increasing the power handling capability and reducing the particle exhaust efficiency of ALT-II. The reduction in exhaust efficiency is unfortunate, but could only be avoided by active cooling of the ALT-II armor tiles. The active cooling option was too complicated and expensive to be considered at this time.

  10. Functional Analysis of All Aminotransferase Proteins Inferred from the Genome Sequence of Corynebacterium glutamicum

    PubMed Central

    Marienhagen, Jan; Kennerknecht, Nicole; Sahm, Hermann; Eggeling, Lothar

    2005-01-01

    Twenty putative aminotransferase (AT) proteins of Corynebacterium glutamicum, or rather pyridoxal-5′-phosphate (PLP)-dependent enzymes, were isolated and assayed among others with l-glutamate, l-aspartate, and l-alanine as amino donors and a number of 2-oxo-acids as amino acceptors. One outstanding AT identified is AlaT, which has a broad amino donor specificity utilizing (in the order of preference) l-glutamate > 2-aminobutyrate > l-aspartate with pyruvate as acceptor. Another AT is AvtA, which utilizes l-alanine to aminate 2-oxo-isovalerate, the l-valine precursor, and 2-oxo-butyrate. A second AT active with the l-valine precursor and that of the other two branched-chain amino acids, too, is IlvE, and both enzyme activities overlap partially in vivo, as demonstrated by the analysis of deletion mutants. Also identified was AroT, the aromatic AT, and this and IlvE were shown to have comparable activities with phenylpyruvate, thus demonstrating the relevance of both ATs for l-phenylalanine synthesis. We also assessed the activity of two PLP-containing cysteine desulfurases, supplying a persulfide intermediate. One of them is SufS, which assists in the sulfur transfer pathway for the Fe-S cluster assembly. Together with the identification of further ATs and the additional analysis of deletion mutants, this results in an overview of the ATs within an organism that may not have been achieved thus far. PMID:16267288

  11. β-Alanine supplementation and military performance.

    PubMed

    Hoffman, Jay R; Stout, Jeffrey R; Harris, Roger C; Moran, Daniel S

    2015-12-01

    During sustained high-intensity military training or simulated combat exercises, significant decreases in physical performance measures are often seen. The use of dietary supplements is becoming increasingly popular among military personnel, with more than half of the US soldiers deployed or garrisoned reported to using dietary supplements. β-Alanine is a popular supplement used primarily by strength and power athletes to enhance performance, as well as training aimed at improving muscle growth, strength and power. However, there is limited research examining the efficacy of β-alanine in soldiers conducting operationally relevant tasks. The gains brought about by β-alanine use by selected competitive athletes appears to be relevant also for certain physiological demands common to military personnel during part of their training program. Medical and health personnel within the military are expected to extrapolate and implement relevant knowledge and doctrine from research performed on other population groups. The evidence supporting the use of β-alanine in competitive and recreational athletic populations suggests that similar benefits would also be observed among tactical athletes. However, recent studies in military personnel have provided direct evidence supporting the use of β-alanine supplementation for enhancing combat-specific performance. This appears to be most relevant for high-intensity activities lasting 60-300 s. Further, limited evidence has recently been presented suggesting that β-alanine supplementation may enhance cognitive function and promote resiliency during highly stressful situations.

  12. Solved? The reductive radiation chemistry of alanine.

    PubMed

    Pauwels, Ewald; De Cooman, Hendrik; Waroquier, Michel; Hole, Eli O; Sagstuen, Einar

    2014-02-14

    The structural changes throughout the entire reductive radiation-induced pathway of l-α-alanine are solved on an atomistic level with the aid of periodic DFT and nudged elastic band (NEB) simulations. This yields unprecedented information on the conformational changes taking place, including the protonation state of the carboxyl group in the "unstable" and "stable" alanine radicals and the internal transformation converting these two radical variants at temperatures above 220 K. The structures of all stable radicals were verified by calculating EPR properties and comparing those with experimental data. The variation of the energy throughout the full radiochemical process provides crucial insight into the reason why these structural changes and rearrangements occur. Starting from electron capture, the excess electron quickly localizes on the carbon of a carboxyl group, which pyramidalizes and receives a proton from the amino group of a neighboring alanine molecule, forming a first stable radical species (up to 150 K). In the temperature interval 150-220 K, this radical deaminates and deprotonates at the carboxyl group, the detached amino group undergoes inversion and its methyl group sustains an internal rotation. This yields the so-called "unstable alanine radical". Above 220 K, triggered by the attachment of an additional proton on the detached amino group, the radical then undergoes an internal rotation in the reverse direction, giving rise to the "stable alanine radical", which is the final stage in the reductive radiation-induced decay of alanine.

  13. Orbiter 'Enterprise' turns and banks during second ALT

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Orbiter 101 'Enterprise' makes a turn and bank maneuver during the second free flight of the Shuttle Apporach and Landing Tests (ALTs) conducted on September 13, 1977 at Dryden Flight Research Center in Southern California. The 'Enterprise' separated form the NASA 747 carrier aircraft and after a five-minute, 28-second unpowered flight landed on a runway below. Astronauts Joe H. Engle, and Richard H. Truly were the crew of the 'Enterprise.' The ALT free flights are designed to verify Orbiter subsonic airworthiness, integrated systems operations and pilot-guided approach and landing capability and satisfying prerequisites to automatic flight control and navigation mode.

  14. Structural analysis and mutant growth properties reveal distinctive enzymatic and cellular roles for the three major L-alanine transaminases of Escherichia coli.

    PubMed

    Peña-Soler, Esther; Fernandez, Francisco J; López-Estepa, Miguel; Garces, Fernando; Richardson, Andrew J; Quintana, Juan F; Rudd, Kenneth E; Coll, Miquel; Vega, M Cristina

    2014-01-01

    In order to maintain proper cellular function, the metabolism of the bacterial microbiota presents several mechanisms oriented to keep a correctly balanced amino acid pool. Central components of these mechanisms are enzymes with alanine transaminase activity, pyridoxal 5'-phosphate-dependent enzymes that interconvert alanine and pyruvate, thereby allowing the precise control of alanine and glutamate concentrations, two of the most abundant amino acids in the cellular amino acid pool. Here we report the 2.11-Å crystal structure of full-length AlaA from the model organism Escherichia coli, a major bacterial alanine aminotransferase, and compare its overall structure and active site composition with detailed atomic models of two other bacterial enzymes capable of catalyzing this reaction in vivo, AlaC and valine-pyruvate aminotransferase (AvtA). Apart from a narrow entry channel to the active site, a feature of this new crystal structure is the role of an active site loop that closes in upon binding of substrate-mimicking molecules, and which has only been previously reported in a plant enzyme. Comparison of the available structures indicates that beyond superficial differences, alanine aminotransferases of diverse phylogenetic origins share a universal reaction mechanism that depends on an array of highly conserved amino acid residues and is similarly regulated by various unrelated motifs. Despite this unifying mechanism and regulation, growth competition experiments demonstrate that AlaA, AlaC and AvtA are not freely exchangeable in vivo, suggesting that their functional repertoire is not completely redundant thus providing an explanation for their independent evolutionary conservation.

  15. β-Alanine Biosynthesis in Methanocaldococcus jannaschii

    PubMed Central

    Wang, Yu; Xu, Huimin

    2014-01-01

    One efficient approach to assigning function to unannotated genes is to establish the enzymes that are missing in known biosynthetic pathways. One group of such pathways is those involved in coenzyme biosynthesis. In the case of the methanogenic archaeon Methanocaldococcus jannaschii as well as most methanogens, none of the expected enzymes for the biosynthesis of the β-alanine and pantoic acid moieties required for coenzyme A are annotated. To identify the gene(s) for β-alanine biosynthesis, we have established the pathway for the formation of β-alanine in this organism after experimentally eliminating other known and proposed pathways to β-alanine from malonate semialdehyde, l-alanine, spermine, dihydrouracil, and acryloyl-coenzyme A (CoA). Our data showed that the decarboxylation of aspartate was the only source of β-alanine in cell extracts of M. jannaschii. Unlike other prokaryotes where the enzyme producing β-alanine from l-aspartate is a pyruvoyl-containing l-aspartate decarboxylase (PanD), the enzyme in M. jannaschii is a pyridoxal phosphate (PLP)-dependent l-aspartate decarboxylase encoded by MJ0050, the same enzyme that was found to decarboxylate tyrosine for methanofuran biosynthesis. A Km of ∼0.80 mM for l-aspartate with a specific activity of 0.09 μmol min−1 mg−1 at 70°C for the decarboxylation of l-aspartate was measured for the recombinant enzyme. The MJ0050 gene was also demonstrated to complement the Escherichia coli panD deletion mutant cells, in which panD encoding aspartate decarboxylase in E. coli had been knocked out, thus confirming the function of this gene in vivo. PMID:24891443

  16. Occurrence of Taurine:α-Ketoglutarate Aminotransferase in Bacterial Extracts1

    PubMed Central

    Toyama, Seizen; Soda, Kenji

    1972-01-01

    High activity of taurine:α-ketoglutarate aminotransferase was found exclusively in cell-free extracts of Achromobacter superficialis and A. polymorph. The former was chosen for characterization of the enzymatic reaction. The enzyme activity was enhanced by addition of β-alanine to the growth medium. The product from α-ketoglutarate was identified as l-glutamate. Another product has been isolated, purified, and identified as sulfoacetaldehyde (2-oxoethanesulfonate), a deamination product from taurine, by comparison between the 2,4-dinitrophenylhydrazones of the synthetic and enzymatic products on the basis of studies by paper chromatography, by visible, infrared, and nuclear magnetic resonance spectrophotometries, and by elemental analysis. This enzymatic transamination was found to proceed stoichiometrically and reversibly as follows: NH2·CH2·CH2·SO3H + HOOC·CH2·CH2·CO·COOH ⇌ OHC·CH2·SO3H + HOOC·CH2·CH2·CH(NH2)·COOH. PMID:5058441

  17. Influence of Asymptomatic Pneumonia on the Response to Hemorrhage and Resuscitation in Swine

    DTIC Science & Technology

    2010-01-01

    dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), amylase and lactate (Vitros Chemistry System...CK. Creatinine increased at 15 min in both groups and remained elevated throughout the study. Mean total protein, amylase and ALT decreased similarly

  18. Antifungal Wound Penetration of Amphotericin and Voriconazole in Combat-related Injuries: Case Report

    DTIC Science & Technology

    2015-04-15

    AST/ALT (IU/L) 193/59 211/318 61/72 INR 1.4 1.4 1.2 Dose interval: 24 hours for L-AmB, 12 hours for voriconazole. Abd, abdomen; AST, aspartate...aminotransferase; ALT, alanine aminotransferase; calc, calcaneus; eGFR, estimated glomerular filtration rate; INR , international normalized ratio; RUE, right

  19. Inhibition of glutamine synthesis induces glutamate dehydrogenase-dependent ammonia fixation into alanine in co-cultures of astrocytes and neurons.

    PubMed

    Dadsetan, Sherry; Bak, Lasse K; Sørensen, Michael; Keiding, Susanne; Vilstrup, Hendrik; Ott, Peter; Leke, Renata; Schousboe, Arne; Waagepetersen, Helle S

    2011-09-01

    It has been previously demonstrated that ammonia exposure of neurons and astrocytes in co-culture leads to net synthesis not only of glutamine but also of alanine. The latter process involves the concerted action of glutamate dehydrogenase (GDH) and alanine aminotransferase (ALAT). In the present study it was investigated if the glutamine synthetase (GS) inhibitor methionine sulfoximine (MSO) would enhance alanine synthesis by blocking the GS-dependent ammonia scavenging process. Hence, co-cultures of neurons and astrocytes were incubated for 2.5h with [U-(13)C]glucose to monitor de novo synthesis of alanine and glutamine in the absence and presence of 5.0 mM NH(4)Cl and 10 mM MSO. Ammonia exposure led to increased incorporation of label but not to a significant increase in the amount of these amino acids. However, in the presence of MSO, glutamine synthesis was blocked and synthesis of alanine increased leading to an elevated content intra- as well as extracellularly of this amino acid. Treatment with MSO led to a dramatic decrease in glutamine content and increased the intracellular contents of glutamate and aspartate. The large increase in alanine during exposure to MSO underlines the importance of the GDH and ALAT biosynthetic pathway for ammonia fixation, and it points to the use of a GS inhibitor to ameliorate the brain toxicity and edema induced by hyperammonemia, events likely related to glutamine synthesis.

  20. Development of the alt Mutant of Pisum sativum L. 1

    PubMed Central

    Guo, Wei Wen; Proebsting, William M.; Potter, Sandra W.; Daley, Larry S.; Potter, John R.

    1987-01-01

    The alt (albina-terminalis) mutant of Pisum sativum L. germinates normally, produces several nodes, and then above a sharp transition produces 2 to 3 bleached nodes, ceases growth, and eventually dies. Green nodes have normal chlorophyll content, absorption spectra, photosynthetic rates, and ultrastructure. In bleaching tissues, the chloroplasts degenerate rapidly, followed by extensive disruption and loss of the remaining cytoplasm and organelles. Application of tissue extracts of normal genotypes of pea, corn, and bean stimulates apical development of alt. The resulting tissues have essentially normal structure and function. Application of thiamine, thiamine monophosphate, and thiamine pyrophosphate also stimulate normal apical development at concentrations of 1 micromolar and above. Partial characterization of the stimulus from pea seed extracts is consistent with thiamine as the active factor. Images Fig. 4 Fig. 6 Fig. 8 PMID:16665809

  1. Unequal hydrolysis of salicylic acid-D-alanine and salicylic acid-L-alanine conjugate in rabbit intestinal microorganisms.

    PubMed

    Nakamura, J; Tagami, C; Nishida, K; Sasaki, H

    1992-02-01

    The behavior of salicylic acid-D-alanine conjugate (salicyl-D-alanine) following intravenous, oral and intracecal administration was examined in rabbits, then compared with that of salicylic acid-L-alanine conjugate (salicyl-L-alanine) as reported previously. Following intravenous administration, salicyl-D-alanine eliminated rapidly from the blood, and its blood concentration was almost identical with that of salicyl-L-alanine. In both cases, salicylic acid could not be detected in the blood, indicating that systemic de-conjugation of D-alanine might not occur. Unchanged salicyl-D-alanine was found in the blood mainly following oral and intracecal administration of salicyl-D-alanine. On the other hand, salicylic acid formed extensively following oral and intracecal administration of salicyl-L-alanine, suggesting that the presystemic de-conjugation of D-alanine and L-alanine was unequal. Furthermore, in vitro incubation of salicyl-D-alanine with cecal content, in which the major source of salicyl-L-alanine hydrolysis is found, showed that the hydrolysis of salicyl-D-alanine was negligible in rabbit intestinal microorganisms.

  2. Understanding and Targeting the ALT Pathway in Human Breast Cancer

    DTIC Science & Technology

    2014-09-01

    by ectopic expression of ESCO2. PLoS One 4, e6936 (2009). 35. Leung, J. W. et al. Alpha thalassemia/ mental retardation syndrome X-linked gene...identified mutations and loss of ATRX protein as being hallmarks of ALT- immortalized cell lines and tumors. Our efforts to understand the mechanism...by which loss of ATRX facilitates telomere recombination have uncovered a novel role for this protein in promoting telomere cohesion. Furthermore

  3. Army AL&T, July-September 2008

    DTIC Science & Technology

    2008-09-01

    4. TITLE AND SUBTITLE Army AL&T, July - September 2008 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Army Acquisition, Logistics & Technology (AT&L...9900 Belvoir Road Suite 101,Fort Belvoir,VA,22060-5567 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS

  4. Aspartate aminotransferase and tylosin biosynthesis in Streptomyces fradiae.

    PubMed Central

    Lee, S H; Lee, K J

    1993-01-01

    Aspartate aminotransferase as well as valine dehydrogenase and threonine dehydratase was required for the biosynthesis of tylosin in Streptomyces fradiae NRRL 2702. The biosynthesis of these enzymes and tylosin production were repressed by high concentrations of ammonium ions. The change in specific tylosin production rates in batch cultures with different initial concentrations of ammonium ions showed patterns similar to those of the specific production rates of aspartate aminotransferase, valine dehydrogenase, and threonine dehydratase. Aspartate aminotransferase has been purified by acetone precipitation, DEAE-cellulose, hydroxyapatite, and preparative electrophoresis chromatographies. The purified enzyme (120 kDa) consisted of two subunits identical in molecular mass (54 kDa) and showed homogeneity, giving one band with a pI of 4.2 upon preparative isoelectric focusing. The enzyme was specific for L-aspartate in the forward reaction; the Km values were determined to be 2.7 mM for L-aspartate, 0.7 mM for 2-oxyglutarate, 12.8 mM for L-glutamate, and 0.15 mM for oxaloacetate. The enzyme was somewhat thermostable, having a maximum activity at 55 degrees C, and had a broad pH optimum that ranged from 5.5 to 8.0. The mode of action was a ping-pong-bi-bi mechanism. Images PMID:8481008

  5. 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...

  6. 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...

  7. 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...

  8. 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 1...

  9. 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 1...

  10. Alternative Liquid Fuels Simulation Model (AltSim).

    SciTech Connect

    Williams, Ryan; Baker, Arnold Barry; Drennen, Thomas E.

    2009-12-01

    The Alternative Liquid Fuels Simulation Model (AltSim) is a high-level dynamic simulation model which calculates and compares the production and end use costs, greenhouse gas emissions, and energy balances of several alternative liquid transportation fuels. These fuels include: corn ethanol, cellulosic ethanol from various feedstocks (switchgrass, corn stover, forest residue, and farmed trees), biodiesel, and diesels derived from natural gas (gas to liquid, or GTL), coal (coal to liquid, or CTL), and coal with biomass (CBTL). AltSim allows for comprehensive sensitivity analyses on capital costs, operation and maintenance costs, renewable and fossil fuel feedstock costs, feedstock conversion ratio, financial assumptions, tax credits, CO{sub 2} taxes, and plant capacity factor. This paper summarizes the structure and methodology of AltSim, presents results, and provides a detailed sensitivity analysis. The Energy Independence and Security Act (EISA) of 2007 sets a goal for the increased use of biofuels in the U.S., ultimately reaching 36 billion gallons by 2022. AltSim's base case assumes EPA projected feedstock costs in 2022 (EPA, 2009). For the base case assumptions, AltSim estimates per gallon production costs for the five ethanol feedstocks (corn, switchgrass, corn stover, forest residue, and farmed trees) of $1.86, $2.32, $2.45, $1.52, and $1.91, respectively. The projected production cost of biodiesel is $1.81/gallon. The estimates for CTL without biomass range from $1.36 to $2.22. With biomass, the estimated costs increase, ranging from $2.19 per gallon for the CTL option with 8% biomass to $2.79 per gallon for the CTL option with 30% biomass and carbon capture and sequestration. AltSim compares the greenhouse gas emissions (GHG) associated with both the production and consumption of the various fuels. EISA allows fuels emitting 20% less greenhouse gases (GHG) than conventional gasoline and diesels to qualify as renewable fuels. This allows several of the CBTL

  11. 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...

  12. 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...

  13. Quick look analysis of an emergency separation for ALT captive-inert flight 1

    NASA Technical Reports Server (NTRS)

    Glenn, G. M.; Seale, R. H.

    1977-01-01

    Emergency separation capability for the landing configuration of ALT Captive Inert Flight Number One was investigated. The quick look analysis confirms emergency separation capability under nominal conditions for the ALT landing configuration. The recommended emergency separation procedure under those conditions is not applicable to all ALT configurations.

  14. Army AL&T, October-December 2007

    DTIC Science & Technology

    2007-12-01

    provides new knowledge and understanding to solve Army-unique problems as well as novel approaches to solve prob- lems with broad and, at times, un- foreseen...metric used to assess tech- nology maturity. The TRL approach was originally established by NASA and adopted by DOD to measure technology maturity...A_ALT_Oct-Dec 2007_V10_CC.qxp 9/25/2007 11:16 PM Page 18 biological mechanisms for the develop- ment of revolutionary approaches to ad- vanced

  15. 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. 21 CFR 172.540 - DL-Alanine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true DL-Alanine. 172.540 Section 172.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents and Related Substances § 172.540 DL-Alanine. DL-Alanine (a racemic mixture of D- and...

  17. On the existence of ‘L-alanine cadmium bromide'

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bikshandarkoil R.

    2013-12-01

    It is argued that the recently reported nonlinear optical crystal L-alanine cadmium bromide, grown by slow solvent evaporation method at room temperature [P. Ilayabarathi, J. Chandrasekaran, Spectrochim. Acta 96A (2012) 684-689] is the well-known L-alanine crystal. The isolation of L-alanine crystal is explained due to fractional crystallization.

  18. On the existence of 'L-alanine cadmium bromide'.

    PubMed

    Srinivasan, Bikshandarkoil R

    2013-12-01

    It is argued that the recently reported nonlinear optical crystal L-alanine cadmium bromide, grown by slow solvent evaporation method at room temperature [P. Ilayabarathi, J. Chandrasekaran, Spectrochim. Acta 96A (2012) 684-689] is the well-known L-alanine crystal. The isolation of L-alanine crystal is explained due to fractional crystallization.

  19. Alternative Liquid Fuels Simulation Model (AltSim).

    SciTech Connect

    Baker, Arnold Barry; Williams, Ryan; Drennen, Thomas E.; Klotz, Richard

    2007-10-01

    The Alternative Liquid Fuels Simulation Model (AltSim) is a high-level dynamic simulation model which calculates and compares the production costs, carbon dioxide emissions, and energy balances of several alternative liquid transportation fuels. These fuels include: corn ethanol, cellulosic ethanol, biodiesel, and diesels derived from natural gas (gas to liquid, or GTL) and coal (coal to liquid, or CTL). AltSim allows for comprehensive sensitivity analyses on capital costs, operation and maintenance costs, renewable and fossil fuel feedstock costs, feedstock conversion efficiency, financial assumptions, tax credits, CO{sub 2} taxes, and plant capacity factor. This paper summarizes the preliminary results from the model. For the base cases, CTL and cellulosic ethanol are the least cost fuel options, at $1.60 and $1.71 per gallon, respectively. Base case assumptions do not include tax or other credits. This compares to a $2.35/gallon production cost of gasoline at September, 2007 crude oil prices ($80.57/barrel). On an energy content basis, the CTL is the low cost alternative, at $12.90/MMBtu, compared to $22.47/MMBtu for cellulosic ethanol. In terms of carbon dioxide emissions, a typical vehicle fueled with cellulosic ethanol will release 0.48 tons CO{sub 2} per year, compared to 13.23 tons per year for coal to liquid.

  20. Factors Predicting HBsAg Seroclearance and Alanine Transaminase Elevation in HBeAg-Negative Hepatitis B Virus-Infected Patients with Persistently Normal Liver Function

    PubMed Central

    Chien, Tai-Long; Wang, Jing-Houng; Kee, Kwong-Ming; Chen, Chien-Hung; Hung, Chao-Hung; Lu, Sheng-Nan

    2016-01-01

    Background A certain proportion of hepatitis B virus (HBV)-infected patients with persistently normal alanine transaminase (ALT) levels have significant fibrosis. Using liver stiffness measurements (Fibroscan®) and laboratory data, including serum ALT, quantitative HBsAg (qHBsAg), and HBV DNA, we attempted to predict the natural histories of these patients. Methods Non-cirrhotic HBeAg-negative chronic hepatitis B patients with persistently normal ALT were followed up prospectively with the end points of HBsAg seroclearance and ALT elevation above the upper limit of normal. The factors that were predictive of the end points were identified. Results A total of 235 patients with an average age of 48.1 +/- 10.7 years were followed up for 7 years. Eight patients (3.4%) lost HBsAg, and 15 patients (6.4%) experienced ALT elevation. The overall cumulative HBsAg seroclearances were 0.4%, 1.3% and 2.3% at years 1, 3 and 5, respectively. Regarding HBsAg seroclearance, the qHBsAg (< 30 IU/ml) cutoff resulted in a hazard ratio (HR) of 19.6 with a 95% confidence interval (CI) of 2.2–166.7 (P = 0.008). The baseline ALT level (odd ratio (OR) 1.075, 95% CI 1.020–1.132, P = 0.006) and a qHBsAg above 1000 IU/ml (3.7, 1.1–12.4, P = 0.032) were associated with ALT elevation. Limited to men, the baseline liver stiffness (1.6, 1.0–2.5, P = 0.031) and a qHBsAg above 1000 IU/ml (10.4, 2.1–52.4, P = 0.004) were factors that were independently associated with ALT elevation. Conclusion A low qHBsAg level predicted HBsAg clearance. Baseline ALT and a qHBsAg above 1000 IU/ml were independent predictive factors for ALT elevation. Among the men, the independent predictive factors for ALT elevation were qHBsAg and liver stiffness. PMID:27935953

  1. Brain alanine formation as an ammonia-scavenging pathway during hyperammonemia: effects of glutamine synthetase inhibition in rats and astrocyte-neuron co-cultures.

    PubMed

    Dadsetan, Sherry; Kukolj, Eva; Bak, Lasse K; Sørensen, Michael; Ott, Peter; Vilstrup, Hendrik; Schousboe, Arne; Keiding, Susanne; Waagepetersen, Helle S

    2013-08-01

    Hyperammonemia is a major etiological toxic factor in the development of hepatic encephalopathy. Brain ammonia detoxification occurs primarily in astrocytes by glutamine synthetase (GS), and it has been proposed that elevated glutamine levels during hyperammonemia lead to astrocyte swelling and cerebral edema. However, ammonia may also be detoxified by the concerted action of glutamate dehydrogenase (GDH) and alanine aminotransferase (ALAT) leading to trapping of ammonia in alanine, which in vivo likely leaves the brain. Our aim was to investigate whether the GS inhibitor methionine sulfoximine (MSO) enhances incorporation of (15)NH4(+) in alanine during acute hyperammonemia. We observed a fourfold increased amount of (15)NH4 incorporation in brain alanine in rats treated with MSO. Furthermore, co-cultures of neurons and astrocytes exposed to (15)NH4Cl in the absence or presence of MSO demonstrated a dose-dependent incorporation of (15)NH4 into alanine together with increased (15)N incorporation in glutamate. These findings provide evidence that ammonia is detoxified by the concerted action of GDH and ALAT both in vivo and in vitro, a mechanism that is accelerated in the presence of MSO thereby reducing the glutamine level in brain. Thus, GS could be a potential drug target in the treatment of hyperammonemia in patients with hepatic encephalopathy.

  2. 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

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

    PubMed

    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. (15)NH(4) 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 (15)N-alanine increased and accumulated as the major amino acid, asparagine synthesis was inhibited, while (15)N-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.

  4. 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

  5. Prevalence and Predictors of Elevated Aspartate Aminotransferase-to-Platelet Ratio Index in Latin American Perinatally HIV-infected Children

    PubMed Central

    Siberry, George K.; Cohen, Rachel A.; Harris, D. Robert; Cruz, Maria Leticia Santos; Oliveira, Ricardo; Peixoto, Mario F.; Cervi, Maria Celia; Hazra, Rohan; Pinto, Jorge A.

    2013-01-01

    Background Chronic liver disease has emerged as an important problem in adults with longstanding HIV infection, but data are lacking for children. We characterized elevated aspartate aminotransferase (AST)-to-platelet ratio index (APRI ), a marker of possible liver fibrosis, in perinatally HIV-infected children. Methods NISDI [NICHD (National Institute of Child Health and Human Development) International Site Development Initiative] enrolled HIV-infected children (ages 0.1-20.1 years) from five Latin American countries in an observational cohort from 2002–2009. Twice yearly visits included medical history, physical examination and laboratory evaluations. The prevalence (95% confidence interval [CI]) of APRI>1.5 was calculated and associations with demographic, HIV-related and liver-related variables were investigated in bivariate analyses. Results APRI was available for 1012 of 1032 children. APRI was >1.5 in 32 (3.2%, 95% CI: 2.2%-4.4%) including 2 of 4 participants with hepatitis B (HBV) infection. Factors significantly associated with APRI>1.5 (p<0.01 compared to APRI≤1.5) included country, younger age, past or current HBV, higher alanine aminotransferase, lower total cholesterol, higher log10 current viral load, lower current CD4 count, lower nadir CD4 count, use of hepatotoxic non-antiretroviral (ARV) medications, and no prior ARV use. Rates of APRI>1.5 varied significantly by current ARV regimen (p=0.0002), from 8.0% for no ARV to 3.2% for non-protease inhibitor (PI) regimens to 1.5% for PI-based regimens. Conclusions Elevated APRI occurred in approximately 3% of perinatally HIV-infected children. PI-based ARVs appeared protective while inadequate HIV control appeared to increase risk of elevated APRI. Additional investigations are needed to better assess potential subclinical, chronic liver disease in HIV-infected children. PMID:23799515

  6. Elevation of alanine transaminase and gallbladder wall abnormalities as biomarkers of anaphylaxis in canine hypersensitivity patients.

    PubMed

    Quantz, Jonnie E; Miles, Macon S; Reed, Ann L; White, George A

    2009-12-01

    The purpose of the study was to evaluate alanine transaminase (ALT) and gallbladder wall abnormalities as possible biomarkers for anaphylaxis in dogs presented for acute hypersensitivity reactions. Pilot study. A private practice, small animal, 24-hour emergency and specialty hospital. Ninety-six dogs presenting 101 times on an emergency basis for hypersensitivity reactions from March 2007 through March 2009. Veterinarians acquired a history, physical exam, serum chemistry panel, blood pressure, and ultrasound image of the gallbladder. Dogs were then divided into 2 groups: dogs fulfilling the definition for anaphylaxis (moderate and severe systemic hypersensitivity) and dogs that did not fulfill the definition and were classified as allergic reactions (local hypersensitivity and mild systemic hypersensitivity). Elevated ALT was significantly associated with anaphylaxis (P<0.001). Increased gallbladder wall thickness and a striated wall pattern were significantly associated with anaphylaxis (P<0.001) and these changes were readily apparent to first-responder veterinarians. Decreased body temperature (P<0.001) and hypothermia (P=0.006) were significantly associated with anaphylaxis. There was no significant difference between groups regarding age, heart rate, or presence of respiratory signs. Lower blood pressure was significantly associated with anaphylaxis (P<0.001) but hypotension was not significantly different (P=0.09) between groups. Cutaneous signs were significantly associated with the allergic reactions group (P<0.001) and, when seen with anaphylaxis, were subtle. This study showed an elevated ALT and an abnormal gallbladder wall to be biomarkers significantly associated with anaphylaxis in dogs with acute hypersensitivity reactions.

  7. NQR in Alanine and Lysine Iodates

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. M.; Burbelo, V. M.; Tamazyan, R. A.; Karapetyan, H. A.; Sukiasyan, R. P.

    2000-02-01

    The structure o f iodates of α- and β-alanine ( Ala) (2(β-Ala • HIO3) • H2O , β-Ala-2HIO3 , D L-Ala• HIO3 • 2H2O, L-Ala • HIO3) and L-lysine (L-Lys) (L-Lys • HIO3, L-Lys • 2HIO3,L-Lys • 3HIO3, L-Lys • 6HIO3) have been investigated by means of iodine-127 NQR, IR spectroscopy and X-ray diffraction

  8. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Pang, Y.

    1995-10-10

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R{sup 1})(R{sup 2})Si--C{triple_bond}C--(R{sup 3})(R{sup 4})Si--CH{double_bond}CH--]{sub n}--, wherein n{>=}2; and each R{sup 1}, R{sup 2}, R{sup 3}, and R{sup 4} is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  9. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1995-10-10

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R.sup.1)(R.sup.2)Si--C.tbd.C--(R.sup.3)(R.sup.4)Si--CH.dbd.CH--].sub .n --, wherein n.gtoreq.2; and each R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  10. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Yi Pang.

    1993-08-31

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: -[-(R[sup 1])(R[sup 2])Si-C[triple bond]C-(R[sup 3])(R[sup 4])Si-CH[double bond]CH-][sub n]-, wherein n[>=]2; each R[sup 1], R[sup 2], R[sup 3], and R[sup 4] is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  11. Studio delle popolazioni di blazar ad alte energie

    NASA Astrophysics Data System (ADS)

    Gasparrini, D.; Giommi, P.

    2008-10-01

    Utilizzando la grande quantita' di dati sui blazar disponibile ad oggi, e' possibile costruire una distribuzione spettrale di energia (SED) media per ciascuna classe di oggetti. Basandosi su un modello SSC, e' inoltre possibile stimare il comportamento di questi oggetti nella banda di energia dei raggi gamma partendo dalle informazioni ottenute da osservazioni in altre bande di energia quali il radio e l'X. Utilizzando le simulazioni sara` possibile prevedere un eventuale cambio di popolazione dominante ad alte energie(oltre 1GeV) rispetto a quanto avviene in banda radio dove domina la popolazione dei FSRQ rispetto ai BL Lac e cercare un'eventuale conferma dagli esperimenti AGILE e GLAST.

  12. Ambient Ionization Mass Spectrometry Measurement of Aminotransferase Activity

    NASA Astrophysics Data System (ADS)

    Yan, Xin; Li, Xin; Zhang, Chengsen; Xu, Yang; Cooks, R. Graham

    2017-01-01

    A change in enzyme activity has been used as a clinical biomarker for diagnosis and is useful in evaluating patient prognosis. Current laboratory measurements of enzyme activity involve multi-step derivatization of the reaction products followed by quantitative analysis of these derivatives. This study simplified the reaction systems by using only the target enzymatic reaction and directly detecting its product. A protocol using paper spray mass spectrometry for identifying and quantifying the reaction product has been developed. Evaluation of the activity of aspartate aminotransferase (AST) was chosen as a proof-of-principle. The volume of sample needed is greatly reduced compared with the traditional method. Paper spray has a desalting effect that avoids sprayer clogging problems seen when examining serum samples by nanoESI. This very simple method does not require sample pretreatment and additional derivatization reactions, yet it gives high quality kinetic data, excellent limits of detection (60 ppb from serum), and coefficients of variation <10% in quantitation.

  13. Synthesis and evaluation of novel heteroaromatic substrates of GABA aminotransferase

    PubMed Central

    Hawker, Dustin D.; Silverman, Richard B.

    2012-01-01

    Two principal neurotransmitters are involved in the regulation of mammalian neuronal activity, namely, γ-aminobutyric acid (GABA), an inhibitory neurotransmitter, and L-glutamic acid, an excitatory neurotransmitter. Low GABA levels in the brain have been implicated in epilepsy and several other neurological diseases. Because of GABA’s poor ability to cross the blood-brain barrier (BBB), a successful strategy to raise brain GABA concentrations is the use of a compound that does cross the BBB and inhibits or inactivates GABA aminotransferase (GABA-AT), the enzyme responsible for GABA catabolism. Vigabatrin, a mechanism-based inactivator of GABA-AT, is currently a successful therapeutic for epilepsy, but has harmful side effects, leaving a need for improved GABA-AT inactivators. Here, we report the synthesis and evaluation of a series of heteroaromatic GABA analogues as substrates of GABA-AT, which will be used as the basis for the design of novel enzyme inactivators. PMID:22944334

  14. Unique substrate specificity of ornithine aminotransferase from Toxoplasma gondii.

    PubMed

    Astegno, Alessandra; Maresi, Elena; Bertoldi, Mariarita; La Verde, Valentina; Paiardini, Alessandro; Dominici, Paola

    2017-03-07

    Toxoplasma gondii is a protozoan parasite of medical and veterinary relevance responsible for toxoplasmosis in humans. As an efficacious vaccine remains a challenge, chemotherapy is still the most effective way to combat the disease. In search of novel druggable targets, we performed a thorough characterization of the putative pyridoxal 5'-phosphate (PLP)-dependent enzyme ornithine aminotransferase from T. gondii ME49 (TgOAT). We overexpressed the protein in Escherichia coli and analysed its molecular and kinetic properties by UV-visible absorbance, fluorescence and CD spectroscopy, in addition to kinetic studies of both the steady state and pre-steady state. TgOAT is largely similar to OATs from other species regarding its general transamination mechanism and spectral properties of PLP; however, it does not show a specific ornithine aminotransferase activity like its human homologue, but exhibits both N-acetylornithine and γ-aminobutyric acid (GABA) transaminase activity in vitro, suggesting a role in both arginine and GABA metabolism in vivo The presence of Val79 in the active site of TgOAT in place of Tyr, as in its human counterpart, provides the necessary room to accommodate N-acetylornithine and GABA, resembling the active site arrangement of GABA transaminases. Moreover, mutation of Val79 to Tyr results in a change of substrate preference between GABA, N-acetylornithine and L-ornithine, suggesting a key role of Val79 in defining substrate specificity. The findings that TgOAT possesses parasite-specific structural features as well as differing substrate specificity from its human homologue make it an attractive target for anti-toxoplasmosis inhibitor design that can be exploited for chemotherapeutic intervention.

  15. Green reduction of graphene oxide using alanine.

    PubMed

    Wang, Jiabin; Salihi, Elif Caliskan; Šiller, Lidija

    2017-03-01

    There remains a real need for the easy, eco-friendly and scalable preparation method of graphene due to various potential applications. Chemical reduction is the most versatile method for the large scale production of graphene. Here we report the operating conditions for a one-step, economical and green synthesis method for the reduction of graphene oxide using a biomolecule (alanine). Graphene oxide was produced by the oxidation and exfoliation of natural graphite flake with strong oxidants using Hummers method (Hummers and Offeman, 1958), but the method was revised in our laboratory to set up a safe and environmentally friendly route. The reduction of graphene oxide was investigated using alanine at various operating conditions in order to set up optimum conditions (treatment time, temperature and concentration of the reagent). Samples have been characterized by using UV-Visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction analysis. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  16. 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.

  17. 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.

  18. Maximization of orbiter altitude at ALT interface airspeed, mission planning, mission analysis and software

    NASA Technical Reports Server (NTRS)

    Glenn, G. M.

    1976-01-01

    The determination of the separation initial conditions (i.e. incidence angle) that maximize orbiter altitude at the ALT interface airspeed is considered. Optimum altitude airspeed profiles are generated for each orbiter incidence angle and tailcone configuration. Results show that the highest separation altitude does not result in the highest altitude at ALT interface airspeed. The altitude attainable at ALT interface airspeed should therefore be considered in the selection of the initial conditions (i.e. incidence angle). Without violating any known constraints, the incidence angles that maximize orbiter altitude at the ALT interface airspeeds are 7.0 deg for ALT free flight 1 and 5.5 deg for ALT free flight 6.

  19. Detailed design specification for the ALT Shuttle Information Extraction Subsystem (SIES)

    NASA Technical Reports Server (NTRS)

    Clouette, G. L.; Fitzpatrick, W. N.

    1976-01-01

    The approach and landing test (ALT) shuttle information extraction system (SIES) is described in terms of general requirements and system characteristics output products and processing options, output products and data sources, and system data flow. The ALT SIES is a data reduction system designed to satisfy certain data processing requirements for the ALT phase of the space shuttle program. The specific ALT SIES data processing requirements are stated in the data reduction complex approach and landing test data processing requirements. In general, ALT SIES must produce time correlated data products as a result of standardized data reduction or special purpose analytical processes. The main characteristics of ALT SIES are: (1) the system operates in a batch (non-interactive) mode; (2) the processing is table driven; (3) it is data base oriented; (4) it has simple operating procedures; and (5) it requires a minimum of run time information.

  20. ALT-711 decreases cardiovascular stiffness and has potential in diabetes, hypertension and heart failure.

    PubMed

    Doggrell, S A

    2001-05-01

    Vascular and/or myocardial stiffness is a major problem in ageing, diabetes, hypertension and heart failure. The development of the stiffness is partly due to the formation of glucose-dependent cross-links in the collagen. ALT-711 cleaves these cross-links. In aged-rhesus monkeys, ALT-711 decreases vascular stiffness and this effect is reversible. ALT-711 also decreases myocardial stiffness in the monkeys but this effect is not reversible in 39 weeks. ALT-711 has potential in the treatment of the stiffness associated with diabetes, hypertension and heart failure.

  1. Tissue Distribution and Subcellular Localization of Prephenate Aminotransferase in Leaves of Sorghum bicolor1

    PubMed Central

    Siehl, Daniel L.; Singh, Bijay K.; Conn, Eric E.

    1986-01-01

    The tissue and subcellular distribution of prephenate aminotransferase, an enzyme of the shikimate pathway, was investigated in protoplasts from leaves of Sorghum bicolor. Activity was detected in purified epidermal and mesophyll protoplasts, and in bundle sheath strands. After fractionation of mesophyll and epidermal protoplasts by differential centrifugation, 92% of the total prephenate aminotransferase activity was detected in the plastid fraction. PMID:16664888

  2. Characterisation of Potential Antimicrobial Targets in Bacillus spp. I. Aminotransferases and Methionine Regeneration in Bacillus subtilis

    DTIC Science & Technology

    2002-07-01

    targets in Bacillus spp. I. Aminotransferases and methionine regeneration in Bacillus subtilis. Bradley J. Berger and Marvin H. Knodel Defence R&D...Characterisation of potential antimicrobial targets in Bacillus spp. I. Aminotransferases and methionine regeneration in Bacillus subtilis. Bradley J...examined in the gram-positive bacterium Bacillus subtilis. Homogenates of this bacterium were able to convert ketomethiobutyrate to methionine, utilising

  3. 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.

  4. Neutral transport in the ALT-I limiter

    SciTech Connect

    Boley, C.D.; Heifetz, D.B.; Post, D.E.; Malinowski, M.E.

    1983-10-01

    The behavior of neutral atoms and molecules in the TEXTOR pump limiter ALT-I has been investigated with the aid of the 2-D Monte Carlo neutral transport code DEGAS. The code incorporates the full set of relevant collision processes (atomic and molecular), and it has a standard wall model which includes fast-neutral reflection and molecular desorption. The limiter was modeled with a 2-D geometry, which included corrections for 3-D effects. Among the quantities predicted by the code which are directly relevant to experiment include the neutral pressure within the plenum and along the duct leading into the plenum, the gettering rates, and the heat flux to the walls of the duct. These have been calculated for a variety of plasma parameters in the inlet, and the behavior with respect to variations of the duct widths has been studied. Because of the presence of the long duct separating the entrance chamber from the plenum, a high probability of ionization generally results, suggesting that a calculation allowing the plasma to adjust to the neutral sources might show a large amount of recycling.

  5. Lysine ε-aminotransferases: kinetic constants, substrate specificities, and the variation in active site residues.

    PubMed

    Seo, Joo-Hyun; Kim, Eun-Mi; Chae, Ahram; Kim, Byung-Gee

    2016-03-01

    L-Lysine ε-aminotransferase (lysAT) is an important enzyme in tailoring the terminal amino group of L-lysine or L-ornithine and can be directed to the synthesis of various value-added chemicals such as adipic acid. Three lysATs, lysAT from Saccharopolyspora erythraea NRRL 2338 (lysAT_Sery), lysAT from Nocardia farcinica IFM 10152, and lysAT from Rhodococcus jostii RHA1, were cloned, and their kinetic values and substrate specificities were investigated. In the reaction using 5mM L-lysine and 10mM α-ketoglutarate, lysAT_Sery from S. erythraea NRRL 2338 showed 72% higher specific activity than lysAT from Nocardia farcinica IFM 10152 and 42% higher specific activity than lysAT from R. jostii RHA1. More interesting result was that lysAT Sery, exhibiting the highest activity among three lysATs, did not show any activity to L-ornithine. The alignment of 146 lysAT sequences from RefSeq database was searched by the EC number of lysAT to compare the active site residues among the lysAT sequences. The sequence alignment showed that only two residues, corresponding to Ala129 and Asn328 of lysAT from Mycobacterium tuberculosis H37Rv (lysAT_Mtub), showed variations among the active site residues. All the active site residues except those two residues were completely conserved throughout 145 lysAT sequences. lysAT from S. erythraea NRRL 2338 has A129T and N328S variations (residue numbers are those of the crystal structure of lysAT_Mtub). The structural analysis by the homology model indicate that Thr126 by A129T variation in lysAT_Sery is appeared to interact more tightly with the phosphate group of PLP than alanine (the distance between Thr126 and the phosphate group of PLP was 2.92Å). In addition, Ser328 is located at the substrate recognition site of active site and, therefore, N328S variation may be connected to the substrate specificity of lysAT. Copyright © 2015. Published by Elsevier Inc.

  6. Crystal structure of the Apo form of D-Alanine:D-Alanine ligase (DDl) from Streptococcus mutans.

    PubMed

    Lu, Yongzhi; Xu, Hongyan; Zhao, Xiaojun

    2010-08-01

    D-Alanine:D-Alanine ligase (DDl) catalyzes the formation of D-Alanine:D-Alanine dipeptide and is an essential enzyme in bacterial cell wall biosynthesis.. This enzyme does not have a human ortholog, making it an attractive target for developing new antibiotic drugs. We determined the crystal structure at 2.23 A resolution of DDl from Streptococcus mutans (SmDDl), the principal aetiological agent of human dental caries. This structure reveals that SmDDl is a dimer and has a disordered omega-loop region.

  7. Design and Mechanism of Tetrahydrothiophene-based GABA Aminotransferase Inactivators

    PubMed Central

    Le, Hoang V.; Hawker, Dustin D.; Wu, Rui; Doud, Emma; Widom, Julia; Sanishvili, Ruslan; Liu, Dali; Kelleher, Neil L.; Silverman, Richard B.

    2015-01-01

    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 analogs 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 eight 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-bond 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

  8. Cloning and expression of human tyrosine aminotransferase cDNA.

    PubMed

    Séralini, G E; Luu-Thé, V; Labrie, F

    1995-01-02

    Complementary DNA clones encoding human tyrosine aminotransferase (TAT) were isolated by screening a normal adult woman liver lambda gt11 library with rat TAT cDNA. The largest isolated cDNA is 2051 bp long (EMBL accession number X55675). This cDNA was subcloned downstream of the cytomegalovirus promoter in the pCMV vector for transfection into human cervical carcinoma HeLa cells. Expression of the TAT cDNA resulted in the synthesis of a protein with a molecular mass of approximately 50 kDa, as assessed by Western analysis, a value which is in close agreement with the predicted molecular weight of 50,399, for a deduced sequence of 454 amino acids. The expressed protein catalyzed specifically the conversion of L-[14C]tyrosine into p-[14C]hydroxyphenylpyruvate. The availability of a functional TAT cDNA provides a useful tool for detailed study of the structure-function relationship of the enzyme and its mutated derivatives.

  9. 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

  10. Ornithine-δ-Aminotransferase Inhibits Neurogenesis During Xenopus Embryonic Development

    PubMed Central

    Peng, Ying; Cooper, Sandra K.; Li, Yi; Mei, Jay M.; Qiu, Shuwei; Borchert, Gregory L.; Donald, Steven P.; Kung, Hsiang-fu; Phang, James M.

    2015-01-01

    Purpose. In humans, deficiency of ornithine-δ-aminotransferase (OAT) results in progressive degeneration of the neural retina (gyrate atrophy) with blindness in the fourth decade. In this study, we used the Xenopus embryonic developmental model to study functions of the OAT gene on embryonic development. Methods. We cloned and sequenced full-length OAT cDNA from Xenopus oocytes (X-OAT) and determined X-OAT expression in various developmental stages of Xenopus embryos and in a variety of adult tissues. The phenotype, gene expression of neural developmental markers, and enzymatic activity were detected by gain-of-function and loss-of-function manipulations. Results. We showed that X-OAT is essential for Xenopus embryonic development, and overexpression of X-OAT produces a ventralized phenotype characterized by a small head, lack of axial structure, and defective expression of neural developmental markers. Using X-OAT mutants based on mutations identified in humans, we found that substitution of both Arg 180 and Leu 402 abrogated both X-OAT enzymatic activity and ability to modulate the developmental phenotype. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development. Conclusions. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development, but it is essential for Xenopus embryonic development. The Arg 180 and Leu 402 are crucial for these effects of the OAT molecule in development. PMID:25783604

  11. Ambient Ionization Mass Spectrometry Measurement of Aminotransferase Activity

    NASA Astrophysics Data System (ADS)

    Yan, Xin; Li, Xin; Zhang, Chengsen; Xu, Yang; Cooks, R. Graham

    2017-06-01

    A change in enzyme activity has been used as a clinical biomarker for diagnosis and is useful in evaluating patient prognosis. Current laboratory measurements of enzyme activity involve multi-step derivatization of the reaction products followed by quantitative analysis of these derivatives. This study simplified the reaction systems by using only the target enzymatic reaction and directly detecting its product. A protocol using paper spray mass spectrometry for identifying and quantifying the reaction product has been developed. Evaluation of the activity of aspartate aminotransferase (AST) was chosen as a proof-of-principle. The volume of sample needed is greatly reduced compared with the traditional method. Paper spray has a desalting effect that avoids sprayer clogging problems seen when examining serum samples by nanoESI. This very simple method does not require sample pretreatment and additional derivatization reactions, yet it gives high quality kinetic data, excellent limits of detection (60 ppb from serum), and coefficients of variation <10% in quantitation. [Figure not available: see fulltext.

  12. Design and Mechanism of Tetrahydrothiophene-based GABA Aminotransferase Inactivators

    SciTech Connect

    Le, Hoang V.; Hawker, Dustin D.; Wu, Rui; Doud, Emma; Widom, Julia; Sanishvili, Ruslan; Liu, Dali; Kelleher, Neil L.; Silverman, Richard B

    2015-04-08

    Low levels of gamma-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinsons disease, Alzheimers disease, Huntingtons 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 bloodbrain barrier and inhibit the activity of gamma-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 pi-pi interaction with Phe-189, and a weak nonbonded (SO)-O-...=C interaction with Glu-270, thereby inactivating the enzyme.

  13. Engineering of alanine dehydrogenase from Bacillus subtilis for novel cofactor specificity.

    PubMed

    Lerchner, Alexandra; Jarasch, Alexander; Skerra, Arne

    2016-09-01

    The l-alanine dehydrogenase of Bacillus subtilis (BasAlaDH), which is strictly dependent on NADH as redox cofactor, efficiently catalyzes the reductive amination of pyruvate to l-alanine using ammonia as amino group donor. To enable application of BasAlaDH as regenerating enzyme in coupled reactions with NADPH-dependent alcohol dehydrogenases, we alterated its cofactor specificity from NADH to NADPH via protein engineering. By introducing two amino acid exchanges, D196A and L197R, high catalytic efficiency for NADPH was achieved, with kcat /KM  = 54.1 µM(-1)  Min(-1) (KM  = 32 ± 3 µM; kcat  = 1,730 ± 39 Min(-1) ), almost the same as the wild-type enzyme for NADH (kcat /KM  = 59.9 µM(-1)  Min(-1) ; KM  = 14 ± 2 µM; kcat  = 838 ± 21 Min(-1) ). Conversely, recognition of NADH was much diminished in the mutated enzyme (kcat /KM  = 3 µM(-1)  Min(-1) ). BasAlaDH(D196A/L197R) was applied in a coupled oxidation/transamination reaction of the chiral dicyclic dialcohol isosorbide to its diamines, catalyzed by Ralstonia sp. alcohol dehydrogenase and Paracoccus denitrificans ω-aminotransferase, thus allowing recycling of the two cosubstrates NADP(+) and l-Ala. An excellent cofactor regeneration with recycling factors of 33 for NADP(+) and 13 for l-Ala was observed with the engineered BasAlaDH in a small-scale biocatalysis experiment. This opens a biocatalytic route to novel building blocks for industrial high-performance polymers.

  14. Alanine repeats influence protein localization in splicing speckles and paraspeckles.

    PubMed

    Chang, Shuo-Hsiu; Chang, Wei-Lun; Lu, Chia-Chen; Tarn, Woan-Yuh

    2014-12-16

    Mammalian splicing regulatory protein RNA-binding motif protein 4 (RBM4) has an alanine repeat-containing C-terminal domain (CAD) that confers both nuclear- and splicing speckle-targeting activities. Alanine-repeat expansion has pathological potential. Here we show that the alanine-repeat tracts influence the subnuclear targeting properties of the RBM4 CAD in cultured human cells. Notably, truncation of the alanine tracts redistributed a portion of RBM4 to paraspeckles. The alanine-deficient CAD was sufficient for paraspeckle targeting. On the other hand, alanine-repeat expansion reduced the mobility of RBM4 and impaired its splicing activity. We further took advantage of the putative coactivator activator (CoAA)-RBM4 conjoined splicing factor, CoAZ, to investigate the function of the CAD in subnuclear targeting. Transiently expressed CoAZ formed discrete nuclear foci that emerged and subsequently separated-fully or partially-from paraspeckles. Alanine-repeat expansion appeared to prevent CoAZ separation from paraspeckles, resulting in their complete colocalization. CoAZ foci were dynamic but, unlike paraspeckles, were resistant to RNase treatment. Our results indicate that the alanine-rich CAD, in conjunction with its conjoined RNA-binding domain(s), differentially influences the subnuclear localization and biogenesis of RBM4 and CoAZ.

  15. Production of the Allergenic Protein Alt a 1 by Alternaria Isolates from Working Environments

    PubMed Central

    Skóra, Justyna; Otlewska, Anna; Gutarowska, Beata; Leszczyńska, Joanna; Majak, Iwona; Stępień, Łukasz

    2015-01-01

    The aim of the study was to evaluate the ability of Alternaria isolates from workplaces to produce Alt a 1 allergenic protein, and to analyze whether technical materials (cellulose, compost, leather) present within the working environment stimulate or inhibit Alt a 1 production (ELISA test). Studies included identification of the isolated molds by nucleotide sequences analyzing of the ITS1/ITS2 regions, actin, calmodulin and Alt a 1 genes. It has been shown that Alternaria molds are significant part of microbiocenosis in the archive, museum, library, composting plant and tannery (14%–16% frequency in the air). The presence of the gene encoding the Alt a 1 protein has been detected for the strains: Alternaria alternata, A. lini, A. limoniasperae A. nobilis and A. tenuissima. Environmental strains produced Alt a 1 at higher concentrations (1.103–6.528 ng/mL) than a ATCC strain (0.551–0.975 ng/mL). It has been shown that the homogenization of the mycelium and the use of ultrafiltration allow a considerable increase of Alt a 1 concentration. Variations in the production of Alt a 1 protein, depend on the strain and extraction methods. These studies revealed no impact of the technical material from the workplaces on the production of Alt a 1 protein. PMID:25689994

  16. Production of the allergenic protein Alt a 1 by Alternaria isolates from working environments.

    PubMed

    Skóra, Justyna; Otlewska, Anna; Gutarowska, Beata; Leszczyńska, Joanna; Majak, Iwona; Stępień, Łukasz

    2015-02-16

    The aim of the study was to evaluate the ability of Alternaria isolates from workplaces to produce Alt a 1 allergenic protein, and to analyze whether technical materials (cellulose, compost, leather) present within the working environment stimulate or inhibit Alt a 1 production (ELISA test). Studies included identification of the isolated molds by nucleotide sequences analyzing of the ITS1/ITS2 regions, actin, calmodulin and Alt a 1 genes. It has been shown that Alternaria molds are significant part of microbiocenosis in the archive, museum, library, composting plant and tannery (14%-16% frequency in the air). The presence of the gene encoding the Alt a 1 protein has been detected for the strains: Alternaria alternata, A. lini, A. limoniasperae A. nobilis and A. tenuissima. Environmental strains produced Alt a 1 at higher concentrations (1.103-6.528 ng/mL) than a ATCC strain (0.551-0.975 ng/mL). It has been shown that the homogenization of the mycelium and the use of ultrafiltration allow a considerable increase of Alt a 1 concentration. Variations in the production of Alt a 1 protein, depend on the strain and extraction methods. These studies revealed no impact of the technical material from the workplaces on the production of Alt a 1 protein.

  17. Switch telomerase to ALT mechanism by inducing telomeric DNA damages and dysfunction of ATRX and DAXX.

    PubMed

    Hu, Yang; Shi, Guang; Zhang, Laichen; Li, Feng; Jiang, Yuanling; Jiang, Shuai; Ma, Wenbin; Zhao, Yong; Songyang, Zhou; Huang, Junjiu

    2016-08-31

    Activation of telomerase or alternative lengthening of telomeres (ALT) is necessary for tumours to escape from dysfunctional telomere-mediated senescence. Anti-telomerase drugs might be effective in suppressing tumour growth in approximately 85-90% of telomerase-positive cancer cells. However, there are still chances for these cells to bypass drug treatment after switching to the ALT mechanism to maintain their telomere integrity. But the mechanism underlying this switch is unknown. In this study, we used telomerase-positive cancer cells (HTC75) to discover the mechanism of the telomerase-ALT switch by inducing telomere-specific DNA damage, alpha-thalassemia X-linked syndrome protein (ATRX) knockdown and deletion of death associated protein (DAXX). Surprisingly, two important ALT hallmarks in the ALT-like HTC75 cells were observed after treatments: ALT-associated promyelocytic leukaemia bodies (APBs) and extrachromosomal circular DNA of telomeric repeats. Moreover, knocking out hTERT by utilizing the CRISPR/Cas9 technique led to telomere elongation in a telomerase-independent manner in ALT-like HTC75 cells. In summary, this is the first report to show that inducing telomeric DNA damage, disrupting the ATRX/DAXX complex and inhibiting telomerase activity in telomerase-positive cancer cells lead to the ALT switch.

  18. Preliminary design analysis of the ALT-II limiter for TEXTOR

    SciTech Connect

    Koski, J.A.; Boyd, R.D.; Kempka, S.M.; Romig, A.D. Jr.; Smith, M.F.; Watson, R.D.; Whitley, J.B.; Conn, R.W.; Grotz, S.P.

    1983-01-01

    Installation of a large toroidal belt pump limiter, Advanced Limiter Test II (ALT-II), on the TEXTOR tokamak at Juelich, FRG is anticipated for early 1986. This paper discusses the preliminary mechanical design and materials considerations undertaken as part of the feasibility study phase for ALT-II.

  19. Some Features of "Alt" Texts Associated with Images in Web Pages

    ERIC Educational Resources Information Center

    Craven, Timothy C.

    2006-01-01

    Introduction: This paper extends a series on summaries of Web objects, in this case, the alt attribute of image files. Method: Data were logged from 1894 pages from Yahoo!'s random page service and 4703 pages from the Google directory; an img tag was extracted randomly from each where present; its alt attribute, if any, was recorded; and the…

  20. Production of D-Alanine by Corynebacterium fascians

    PubMed Central

    Yamada, Shigeki; Maeshima, Haruko; Wada, Mitsuru; Chibata, Ichiro

    1973-01-01

    A strain identified as Corynebacterium fascians was found to accumulate extracellular D-alanine from glycerol. Cultural conditions for the accumulation of D-alanine were investigated and, as a result, a yield of 7 g of D-alanine per liter was obtained after a 96-h incubation in a medium containing 5% glycerol, 4% (NH4)2HPO4, and 0.3% corn steep liquor. Optical purity of D-alanine was dependent upon the concentration of corn steep liquor. At the optimal condition, almost optically pure D-alanine was formed and readily isolated (5 g/liter) from the fermentation broth. The product was not contaminated with any detectable amount of other amino acids, except for glycine which was present at a concentration of less than 1 percent. PMID:4699220

  1. Mechanisms of itch evoked by β-alanine.

    PubMed

    Liu, Qin; Sikand, Parul; Ma, Chao; Tang, Zongxiang; Han, Liang; Li, Zhe; Sun, Shuohao; LaMotte, Robert H; Dong, Xinzhong

    2012-10-17

    β-Alanine, a popular supplement for muscle building, induces itch and tingling after consumption, but the underlying molecular and neural mechanisms are obscure. Here we show that, in mice, β-alanine elicited itch-associated behavior that requires MrgprD, a G-protein-coupled receptor expressed by a subpopulation of primary sensory neurons. These neurons exclusively innervate the skin, respond to β-alanine, heat, and mechanical noxious stimuli but do not respond to histamine. In humans, intradermally injected β-alanine induced itch but neither wheal nor flare, suggesting that the itch was not mediated by histamine. Thus, the primary sensory neurons responsive to β-alanine are likely part of a histamine-independent itch neural circuit and a target for treating clinical itch that is unrelieved by anti-histamines.

  2. Mechanisms of itch evoked by β-alanine

    PubMed Central

    Liu, Qin; Sikand, Parul; Ma, Chao; Tang, Zongxiang; Han, Liang; Li, Zhe; Sun, Shuohao; LaMotte, Robert H.; Dong, Xinzhong

    2012-01-01

    β-alanine, a popular supplement for muscle building, induces itch and tingling after consumption, but the underlying molecular and neural mechanisms are obscure. Here we show that, in mice, β-alanine elicited itch-associated behavior that requires MrgprD, a G protein-coupled receptor expressed by a subpopulation of primary sensory neurons. These neurons exclusively innervate the skin, respond to β-alanine, heat and mechanical noxious stimuli but do not respond to histamine. In humans, intradermally injected β-alanine induced itch but neither wheal nor flare suggesting that the itch was not mediated by histamine. Thus, the primary sensory neurons responsive to β-alanine are likely part of a histamine-independent itch neural circuit and a target for treating clinical itch that is unrelieved by anti-histamines. PMID:23077038

  3. The structure of alanine racemase from Acinetobacter baumannii.

    PubMed

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

    2014-09-01

    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.

  4. Expression and processing of human ornithine-delta-aminotransferase in Saccharomyces cerevisiae.

    PubMed

    Dougherty, K M; Swanson, D A; Brody, L C; Valle, D

    1993-11-01

    Ornithine-delta-aminotransferase catalyzes the conversion of ornithine to glutamate-gamma-semialdehyde. In humans, deficiency of this mitochondrial matrix enzyme results in the progressive blinding disorder, gyrate atrophy of the choroid and retina. To explore yeast as an expression system, we introduced a cDNA encoding human ornithine-delta-aminotransferase into an ornithine aminotransferase-deficient strain of Saccharomyces cerevisiae. The human enzyme was expressed at high levels, with activity 20-fold greater than that of wild-type yeast and 10-fold higher than in human fibroblasts. Although the normal location of ornithine-delta-aminotransferase in S. cerevisiae is cytosolic, human ornithine-delta-aminotransferase expressed in S. cerevisiae was localized to the mitochondrial matrix with correct proteolytic processing of its mitochondrial leader sequence. Despite this anomalous location in yeast, human ornithine-delta-aminotransferase complemented the phenotype of the mutant strain, restoring its ability to utilize ornithine as a sole nitrogen source. We also expressed a vitamin B6-responsive missense allele of ornithine-delta-aminotransferase (V332M) and showed that the biochemical phenotype of this allele is easily demonstrated confirming the usefulness of this system for examining mutations causing gyrate atrophy.

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

    PubMed

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

    2011-02-25

    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 (2)H(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'-(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 (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 (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 (2)H. The method was highly sensitive that for the aminotransferase with ca. 50 kDa subunit molecular weight, only 2mg 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.

  6. 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.

  7. Evaluation of Preoperative Aspartate Transaminase/Alanine Transaminase Ratio as an Independent Predictive Biomarker in Patients With Metastatic Renal Cell Carcinoma Undergoing Cytoreductive Nephrectomy: A Propensity Score Matching Study.

    PubMed

    Ishihara, Hiroki; Kondo, Tsunenori; Yoshida, Kazuhiko; Omae, Kenji; Takagi, Toshio; Iizuka, Junpei; Tanabe, Kazunari

    2017-10-01

    The usefulness of the aspartate transaminase (AST)/alanine transaminase (ALT) ratio (De Ritis ratio) as a predictive biomarker for patients with metastatic renal cell carcinoma (mRCC) undergoing cytoreductive nephrectomy (CN) remains unclear. The data from 118 patients were retrospectively evaluated. The endpoints were cancer-specific survival (CSS) and overall survival (OS) after CN. We compared these according to the AST/ALT ratio before and after 1:1 propensity score matching. The independent predictors for CSS and OS were also analyzed. The area under the receiver operating characteristic curve was 0.603. The maximum Youden index indicated that the cutoff value for the AST/ALT ratio was 1.24. Before matching, a high AST/ALT ratio was significantly associated with inferior CSS and OS (P < .05 for all). After matching, 34 patients each were allocated to the high and low AST/ALT ratio groups. In the matched cohort, CSS and OS tended to be lower in the high AST/ALT ratio group, although the results were not statistically significant (median CSS, 18.4 months vs. not reached, P = .121; OS, 18.4 months vs. not reached, P = .0957). Furthermore, multivariate analyses revealed that the AST/ALT ratio was an independent predictor for CSS and OS (CSS hazard ratio, 2.17, P = .0472; OS hazard ratio, 2.30, P = .0258). The preoperative AST/ALT ratio can be an effective predictive biomarker for CSS and OS in patients with mRCC. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. 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.

  9. 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.

  10. Purification and properties of 7, 8-diaminopelargonic acid aminotransferase.

    PubMed

    Stoner, G L; Eisenberg, M A

    1975-06-10

    The enzyme 7, 8-diaminopelargonic acid aminotransferase utilizes S-adenosyl-L-methionine to transaminate the biotin precurson 7-keto-8-aminopelargonic acid and form the next intermediate in the pathway, 7, 8-diaminopelargonic acid. The enzyme has been purified nearly 1000-fold from an extract of a regulatory mutant of Escherichia coli which is derepressed for the enzymes of the biotin operon. The extract was treated with protamine sulfate, ammonium sulfate, and subjected to acid and heat treatments. Subsequently, the enzyme was chromatographed on columns of DEAE-cellulose, phosphocellulose, hydroxylapatite, and two Sephadex G-100. The resulting purified preparation was judged 86% homogeneous by the scanning of of a stained disc gel. The enzymatic activity was associated with the major band in gels run at two different gel concentrations and two different pH values. The cofactor, pyridoxal phosphate, can be resolved from the enzyme in the presence of phosphate buffer after incubation with the amino donor, S-adenosyl-L-methionine. A molecular weight estimation of 94,000 plus or minus 10, 000 has been obtained by gel filtration and sucrose gradient sedimentation studies. Gel electrophoresis in the presence of sodium dodecyl sulfate, shows a single subunit with a molecular weight of 47, 000 plus or minus 3, 000 indicating a dimeric enzyme. A neutral compound was detected in the acidified reaction mixture which was derived from the methionine moiety of S-adenosyl-L-methionine and was present in amounts equivalent to the 7, 8-diaminopelargonic acid produced in the reaction mixture. It is suggested that the keto product of the reaction, i.e. S-adenosyl-2-oxo-4-methylthiobutyric acid, may decompose nonenzymatically under the conditions of the reaction to form 5'-methylthioadenosine and the neutral compound, 2-oxo-3-butenoic acid.

  11. 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.

  12. Biochemical and Structural Properties of Mouse Kynurenine Aminotransferase III▿

    PubMed Central

    Han, Qian; Robinson, Howard; Cai, Tao; Tagle, Danilo A.; Li, Jianyong

    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 60°C. 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. PMID:19029248

  13. Tyrosine aminotransferase contributes to benzylisoquinoline alkaloid biosynthesis in opium poppy.

    PubMed

    Lee, Eun-Jeong; Facchini, Peter J

    2011-11-01

    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 K(m) 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.

  14. Aspartate Aminotransferase in Effective and Ineffective Alfalfa Nodules 1

    PubMed Central

    Gantt, J. Stephen; Larson, Ruby J.; Farnham, Mark W.; Pathirana, Sudam M.; Miller, Susan S.; Vance, Carroll P.

    1992-01-01

    Aspartate aminotransferase (AAT) is a key plant enzyme affecting nitrogen and carbon metabolism, particularly in legume root nodules and leaves of C4 species. To ascertain the molecular genetic characteristics and biochemical regulation of AAT, we have isolated a cDNA encoding the nodule-enhanced AAT (AAT-2) of alfalfa (Medicago sativa L.) by screening a root nodule cDNA expression library with antibodies. Complementation of an Escherichia coli AAT mutant with the alfalfa nodule AAT-2 cDNA verified the identity of the clone. The deduced amino acid sequence of alfalfa AAT-2 is 53 and 47% identical to animal mitochondrial and cytosolic AATs, respectively. The deduced molecular mass of AAT-2 is 50,959 daltons, whereas the mass of purified AAT-2 is about 40 kilodaltons as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the protein's N-terminal domain (amino acids 1-59) contains many of the characteristics of plastid-targeting peptides. We postulate that AAT-2 is localized to the plastid. Southern blot analysis suggests that AAT-2 is encoded by a small, multigene family. The expression of AAT-2 mRNA in nodules is severalfold greater than that in either leaves or roots. Northern and western blots showed that expression of AAT activity during effective nodule development is accompanied by a sevenfold increase in AAT-2 mRNA and a comparable increase in enzyme protein. By contrast, plant-controlled ineffective nodules express AAT-2 mRNA at much lower levels and have little to no AAT-2 enzyme protein. Expression of root nodule AAT-2 appears to be regulated by at least two events: the first is independent of nitrogenase activity; the second is associated with nodule effectiveness. ImagesFigure 3Figure 4Figure 5Figure 7Figure 8 PMID:16668758

  15. 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.

  16. New use of an old drug: chloroquine reduces viral and ALT levels in HCV non-responders (a randomized, triple-blind, placebo-controlled pilot trial).

    PubMed

    Peymani, Payam; Yeganeh, Behzad; Sabour, Siamak; Geramizadeh, Bita; Fattahi, Mohammad Reza; Keyvani, Hossein; Azarpira, Negar; Coombs, Kevin M; Ghavami, Saied; Lankarani, Kamran B

    2016-06-01

    Hepatitis C virus (HCV) infection induces autophagy, but the virus assimilates the autophagic response into its own life cycle. Chloroquine (CQ) is an autophagy inhibitor that is clinically used to treat malaria. The aims of this pilot clinical trial were to evaluate the therapeutic potential and short-term safety of CQ in patients with chronic HCV genotype 1, who were unresponsive to a combination of pegylated interferon alpha and ribavirin. Ten non-responders to previous antiviral treatment(s) were randomized to receive either CQ (150 mg daily for 8 weeks) or placebo, and were followed for 4 weeks after CQ therapy. HCV RNA load and plasma alanine transaminase (ALT) levels were measured at baseline, week 4 (initial response), week 8 (end-of-treatment response), and at the end of 12 weeks. A significant decrease in HCV RNA after the treatments (week 8) was observed in all patients in the CQ group (P = 0.04). However, HCV RNA levels increased within 4 weeks after discontinuation of CQ treatment although they were still lower than baseline. In addition, the ALT normalized during treatment in the CQ group. However, this response was also lost after treatment cessation. This study provides preliminary evidence that CQ is possibly a safe treatment option for HCV non-responders.

  17. 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.

  18. β-Alanine supplementation for athletic performance: an update.

    PubMed

    Bellinger, Phillip M

    2014-06-01

    β-alanine supplementation has become a common practice among competitive athletes participating in a range of different sports. Although the mechanism by which chronic β-alanine supplementation could have an ergogenic effect is widely debated, the popular view is that β-alanine supplementation augments intramuscular carnosine content, leading to an increase in muscle buffer capacity, a delay in the onset of muscular fatigue, and a facilitated recovery during repeated bouts of high-intensity exercise. β-alanine supplementation appears to be most effective for exercise tasks that rely heavily on ATP synthesis from anaerobic glycolysis. However, research investigating its efficacy as an ergogenic aid remains equivocal, making it difficult to draw conclusions as to its effectiveness for training and competition. The aim of this review was to update, summarize, and critically evaluate the findings associated with β-alanine supplementation and exercise performance with the most recent research available to allow the development of practical recommendations for coaches and athletes. A critical review of the literature reveals that when significant ergogenic effects have been found, they have been generally shown in untrained individuals performing exercise bouts under laboratory conditions. The body of scientific data available concerning highly trained athletes performing single competition-like exercise tasks indicates that this type of population receives modest but potentially worthwhile performance benefits from β-alanine supplementation. Recent data indicate that athletes may not only be using β-alanine supplementation to enhance sports performance but also as a training aid to augment bouts of high-intensity training. β-alanine supplementation has also been shown to increase resistance training performance and training volume in team-sport athletes, which may allow for greater overload and superior adaptations compared with training alone. The ergogenic

  19. Characterisation of a flavonoid ligand of the fungal protein Alt a 1

    PubMed Central

    Garrido-Arandia, María; Silva-Navas, Javier; Ramírez-Castillejo, Carmen; Cubells-Baeza, Nuria; Gómez-Casado, Cristina; Barber, Domingo; Pozo, Juan C.; Melendi, Pablo G.; Pacios, Luis F.; Díaz-Perales, Araceli

    2016-01-01

    Spores of pathogenic fungi are virtually ubiquitous and cause human disease and severe losses in crops. The endophytic fungi Alternaria species produce host-selective phytotoxins. Alt a 1 is a strongly allergenic protein found in A. alternata that causes severe asthma. Despite the well-established pathogenicity of Alt a 1, the molecular mechanisms underlying its action and physiological function remain largely unknown. To gain insight into the role played by this protein in the pathogenicity of the fungus, we studied production of Alt a 1 and its activity in spores. We found that Alt a 1 accumulates inside spores and that its release with a ligand is pH-dependent, with optimum production in the 5.0–6.5 interval. The Alt a 1 ligand was identified as a methylated flavonoid that inhibits plant root growth and detoxifies reactive oxygen species. We also found that Alt a 1 changes its oligomerization state depending on the pH of the surrounding medium and that these changes facilitate the release of the ligand. Based on these results, we propose that release of Alt a 1 should be a pathogenic target in approaches used to block plant defenses and consequently to favor fungal entry into the plant. PMID:27633190

  20. Variant repeats are interspersed throughout the telomeres and recruit nuclear receptors in ALT cells

    PubMed Central

    Conomos, Dimitri; Stutz, Michael D.; Hills, Mark; Neumann, Axel A.; Bryan, Tracy M.

    2012-01-01

    Telomeres in cells that use the recombination-mediated alternative lengthening of telomeres (ALT) pathway elicit a DNA damage response that is partly independent of telomere length. We therefore investigated whether ALT telomeres contain structural abnormalities that contribute to ALT activity. Here we used next generation sequencing to analyze the DNA content of ALT telomeres. We discovered that variant repeats were interspersed throughout the telomeres of ALT cells. We found that the C-type (TCAGGG) variant repeat predominated and created a high-affinity binding site for the nuclear receptors COUP-TF2 and TR4. Nuclear receptors were directly recruited to telomeres and ALT-associated characteristics were induced after incorporation of the C-type variant repeat by a mutant telomerase. We propose that the presence of variant repeats throughout ALT telomeres results from recombination-mediated telomere replication and spreading of variant repeats from the proximal regions of the telomeres and that the consequent binding of nuclear receptors alters the architecture of telomeres to facilitate further recombination. PMID:23229897

  1. Association of the I148M/PNPLA3 variant with elevated alanine transaminase levels in normal-weight and overweight/obese Mexican children.

    PubMed

    Larrieta-Carrasco, Elena; León-Mimila, Paola; Villarreal-Molina, Teresa; Villamil-Ramírez, Hugo; Romero-Hidalgo, Sandra; Jacobo-Albavera, Leonor; Gutiérrez-Vidal, Roxana; López-Contreras, Blanca E; Guillén-Pineda, Luz E; Sánchez-Muñoz, Fausto; Bojalil, Rafael; Mejía-Domínguez, Ana M; Méndez-Sánchez, Nahúm; Domínguez-López, Aaron; Aguilar-Salinas, Carlos A; Canizales-Quinteros, Samuel

    2013-05-15

    Non-alcoholic fatty liver disease (NAFLD) and elevated alanine transaminase (ALT) levels are common in obese Hispanic adults and children. Recently, a PNPLA3 gene variant (I148M) was strongly associated with NAFLD and higher ALT levels in obese adults, including Hispanics. The aims of this study were to estimate the frequency of elevated ALT levels, and to address the influence of obesity and PNPLA3/I148M on ALT levels in a general population sample of Mexican school-aged children. A total of 1037 non-related Mexican children aged 6 to 12 years were genotyped for the I148M variant. Anthropometric, clinical and metabolic parameters were collected from all participants. Elevated ALT levels (>35 U/L) were more frequent in obese (26.9%) and overweight (9.3%) than in normal weight children (2.2%). The M148M genotype was significantly associated with elevated ALT levels in this population (OR=3.7, 95% CI 2.3-5.9; P=3.7×10(-8)), and children carrying the M148M genotype showed significantly lower HDL cholesterol levels and BMI z-core (P=0.036 and 0.015, respectively). On stratifying by BMI percentile, this genotype conferred a much greater risk of elevated ALT levels in normal weight (OR=19.9, 95% CI 2.5-157.7; P=0.005) than overweight and obese children (OR=3.4, 95% CI 1.3-8.9; P=0.014 and OR=3.1, 95% CI 1.7-5.5; P=1.4 x10(-4), respectively). The I148M PNPLA3 variant is strongly associated with elevated ALT levels in normal weight and overweight/obese Mexican children. Thus, the M148M genotype may be considered as an important risk factor for liver damage in this population. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. An alternate method for demonstration of erythrocytic aminotransferases on starch gels

    PubMed Central

    Scott, Edward M.; Wright, Rita C.

    1981-01-01

    A two-stage procedure using MTT tetrazolium for the demonstration of aminotransferases (GPT and GOT) either singly or together was developed. Identification of phenotypes was unequivocal in over 99% of the individuals studied. ImagesFig. 1 PMID:7258187

  3. Plastidic aspartate aminotransferases and the biosynthesis of essential amino acids in plants.

    PubMed

    de la Torre, Fernando; Cañas, Rafael A; Pascual, M Belén; Avila, Concepción; Cánovas, Francisco M

    2014-10-01

    In the chloroplasts and in non-green plastids of plants, aspartate is the precursor for the biosynthesis of different amino acids and derived metabolites that play distinct and important roles in plant growth, reproduction, development or defence. Aspartate biosynthesis is mediated by the enzyme aspartate aminotransferase (EC 2.6.1.1), which catalyses the reversible transamination between glutamate and oxaloacetate to generate aspartate and 2-oxoglutarate. Plastids contain two aspartate aminotransferases: a eukaryotic-type and a prokaryotic-type bifunctional enzyme displaying aspartate and prephenate aminotransferase activities. A general overview of the biochemistry, regulation, functional significance, and phylogenetic origin of both enzymes is presented. The roles of these plastidic aminotransferases in the biosynthesis of essential amino acids are discussed.

  4. Chronotypic induction of tyrosine aminotransferase by. cap alpha. -methyl-p-tyrosine. [Rat liver

    SciTech Connect

    Cahill, A.L.; Ferguson, S.M.; Ehret, C.F.

    1981-04-06

    ..cap alpha..Methyl-p-tyrosine induced hepatic tyrosine aminotransferase activity to different extents depending upon the time of day of administration of the drug. Maximal induction occurred when ..cap alpha..-methyl-p-tyrosine (100 mg/kg) was injected intraperitoneally during the first several hours of the light phase of the daily cycle, but the magnitude of the induction depended on the nutritional state of the animal. Induction was 4- to 5-fold greater in fasting rats. The effect of ..cap alpha..-methyl-ptyrosine on hepatic tyrosine aminotransferase is believed to be mediated by decreases in hypothalamic norepinephrine. This hypothesis was supported by the demonstration that decreasing levels of hypothalamic norepinephrine at times of day when hypothalamic turnover of norepinephrine was greatest resulted in the greatest induction of tyrosine aminotransferase, while lowering hypothalamic norepinephrine at times when turnover was minimal resulted in minimal induction of tyrosine aminotransferase.

  5. Subcellular Localization of Asparaginase and Asparagine Aminotransferase in Pisum sativum Leaves 1

    PubMed Central

    Ireland, Robert J.; Joy, Kenneth W.

    1983-01-01

    Protoplasts isolated from young and mature pea leaves (Pisum sativum L.) were broken and their contents fractionated by differential centrifugation or on sucrose-density gradients. Asparaginase was found only in the cytosol of young leaves. Asparagine aminotransferase was found in both young and mature leaves and was localized exclusively in the peroxisome. This corroborates the observation that asparagine transamination is catalyzed by the serine:glyoxylate aminotransferase. PMID:16663132

  6. Post-test navigation data analysis techniques for the shuttle ALT

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Postflight test analysis data processing techniques for shuttle approach and landing tests (ALT) navigation data are defined. Postfight test processor requirements are described along with operational and design requirements, data input requirements, and software test requirements. The postflight test data processing is described based on the natural test sequence: quick-look analysis, postflight navigation processing, and error isolation processing. Emphasis is placed on the tradeoffs that must remain open and subject to analysis until final definition is achieved in the shuttle data processing system and the overall ALT plan. A development plan for the implementation of the ALT postflight test navigation data processing system is presented. Conclusions are presented.

  7. Primary structure of a key enzyme in plant tetrapyrrole synthesis: glutamate 1-semialdehyde aminotransferase.

    PubMed Central

    Grimm, B

    1990-01-01

    The formation of delta-aminolevulinate from glutamate 1-semialdehyde (GSA) is catalyzed by glutamate 1-semialdehyde aminotransferase (EC 5.4.3.8). The active form of the barley enzyme appears to be a dimer of identical subunits with a molecular mass of 46 kDa. From the purified enzyme, amino acid sequences of the N-terminal ends of the mature protein as well as an internal peptide were determined. DNA primers deduced from these peptide sequences were used to amplify with the polymerase chain reaction a cDNA sequence encoding part of the enzyme. Screening a cDNA library with this DNA fragment identified a full-length clone encoding the 49,540-Da precursor of the GSA aminotransferase. The transit peptide for chloroplast import consists of 34 amino acids. GSA aminotransferase and a precursor form were expressed on a multicopy plasmid in Escherichia coli. Both recombinant gene products reacted with an antibody against the barley GSA aminotransferase. Active barley GSA aminotransferase expressed in E. coli was shown to be active in assays of bacterial cell extracts. As a gene symbol for barley GSA aminotransferase, Gsa is proposed. Images PMID:2349227

  8. Function of the D-alanine:D-alanine ligase lid loop: a molecular modeling and bioactivity study.

    PubMed

    Hrast, Martina; Vehar, Blaž; Turk, Samo; Konc, Janez; Gobec, Stanislav; Janežič, Dušanka

    2012-08-09

    D-Alanine:D-alanine ligase (Ddl) is an essential ATP-dependent bacterial enzyme involved in peptidoglycan biosynthesis. Discovery of Ddl inhibitors not competitive with ATP has proven to be difficult because the Ddl bimolecular d-alanine binding pocket is very restricted, as is accessibility to the active site for larger molecules in the catalytically active closed conformation of Ddl. A molecular dynamics study of the opening and closing of the Ddl lid loop informs future structure-based design efforts that allow for the flexibility of Ddl. A virtual screen on generated enzyme conformations yielded some hit inhibitors whose bioactivity was determined.

  9. The Role of ATRX in the Alternative Lengthening of Telomeres (ALT) Phenotype

    PubMed Central

    Amorim, João P.; Santos, Gustavo; Vinagre, João; Soares, Paula

    2016-01-01

    Telomeres are responsible for protecting chromosome ends in order to prevent the loss of coding DNA. Their maintenance is required for achieving immortality by neoplastic cells and can occur by upregulation of the telomerase enzyme or through a homologous recombination-associated process, the alternative lengthening of telomeres (ALT). The precise mechanisms that govern the activation of ALT or telomerase in tumor cells are not fully understood, although cellular origin may favor one of the other mechanisms that have been found thus far in mutual exclusivity. Specific mutational events influence ALT activation and maintenance: a unifying frequent feature of tumors that acquire this phenotype are the recurrent mutations of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) or Death-Domain Associated Protein (DAXX) genes. This review summarizes the established criteria about this phenotype: its prevalence, theoretical molecular mechanisms and relation with ATRX, DAXX and other proteins (directly or indirectly interacting and resulting in the ALT phenotype). PMID:27657132

  10. The Role of ATRX in the Alternative Lengthening of Telomeres (ALT) Phenotype.

    PubMed

    Amorim, João P; Santos, Gustavo; Vinagre, João; Soares, Paula

    2016-09-19

    Telomeres are responsible for protecting chromosome ends in order to prevent the loss of coding DNA. Their maintenance is required for achieving immortality by neoplastic cells and can occur by upregulation of the telomerase enzyme or through a homologous recombination-associated process, the alternative lengthening of telomeres (ALT). The precise mechanisms that govern the activation of ALT or telomerase in tumor cells are not fully understood, although cellular origin may favor one of the other mechanisms that have been found thus far in mutual exclusivity. Specific mutational events influence ALT activation and maintenance: a unifying frequent feature of tumors that acquire this phenotype are the recurrent mutations of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) or Death-Domain Associated Protein (DAXX) genes. This review summarizes the established criteria about this phenotype: its prevalence, theoretical molecular mechanisms and relation with ATRX, DAXX and other proteins (directly or indirectly interacting and resulting in the ALT phenotype).

  11. Differential Evolutionary Selection and Natural Evolvability Observed in ALT Proteins of Human Filarial Parasites.

    PubMed

    Devoe, Neil C; Corbett, Ian J; Barker, Linsey; Chang, Robert; Gudis, Polyxeni; Mullen, Nathan; Perez, Kailey; Raposo, Hugo; Scholz, John; May, Meghan

    2016-01-01

    The abundant larval transcript (ALT-2) protein is present in all members of the Filarioidea, and has been reported as a potential candidate antigen for a subunit vaccine against lymphatic filariasis. To assess the potential for vaccine escape or heterologous protection, we examined the evolutionary selection acting on ALT-2. The ratios of nonsynonymous (K(a)) to synonymous (K(s)) mutation frequencies (ω) were calculated for the alt-2 genes of the lymphatic filariasis agents Brugia malayi and Wuchereria bancrofti and the agents of river blindness and African eyeworm disease Onchocerca volvulus and Loa loa. Two distinct Bayesian models of sequence evolution showed that ALT-2 of W. bancrofti and L. loa were under significant (P<0.05; P < 0.001) diversifying selection, while ALT-2 of B. malayi and O. volvulus were under neutral to stabilizing selection. Diversifying selection as measured by ω values was notably strongest on the region of ALT-2 encoding the signal peptide of L. loa and was elevated in the variable acidic domain of L. loa and W. bancrofti. Phylogenetic analysis indicated that the ALT-2 consensus sequences formed three clades: the first consisting of B. malayi, the second consisting of W. bancrofti, and the third containing both O. volvulus and L. loa. ALT-2 selection was therefore not predictable by phylogeny or pathology, as the two species parasitizing the eye were selected differently, as were the two species parasitizing the lymphatic system. The most immunogenic regions of L. loa and W. bancrofti ALT-2 sequence as modeled by antigenicity prediction analysis did not correspond with elevated levels of diversifying selection, and were not selected differently than predicted antigenic epitopes in B. malayi and O. volvulus. Measurements of ALT-2 evolvability made by χ2 analysis between alleles that were stable (O. volvulus and B. malayi) and those that were under diversifying selection (W. bancrofti and L. loa) indicated significant (P<0

  12. Differential Evolutionary Selection and Natural Evolvability Observed in ALT Proteins of Human Filarial Parasites

    PubMed Central

    Devoe, Neil C.; Corbett, Ian J.; Barker, Linsey; Chang, Robert; Gudis, Polyxeni; Mullen, Nathan; Perez, Kailey; Raposo, Hugo; Scholz, John; May, Meghan

    2016-01-01

    The abundant larval transcript (ALT-2) protein is present in all members of the Filarioidea, and has been reported as a potential candidate antigen for a subunit vaccine against lymphatic filariasis. To assess the potential for vaccine escape or heterologous protection, we examined the evolutionary selection acting on ALT-2. The ratios of nonsynonymous (K(a)) to synonymous (K(s)) mutation frequencies (ω) were calculated for the alt-2 genes of the lymphatic filariasis agents Brugia malayi and Wuchereria bancrofti and the agents of river blindness and African eyeworm disease Onchocerca volvulus and Loa loa. Two distinct Bayesian models of sequence evolution showed that ALT-2 of W. bancrofti and L. loa were under significant (P<0.05; P < 0.001) diversifying selection, while ALT-2 of B. malayi and O. volvulus were under neutral to stabilizing selection. Diversifying selection as measured by ω values was notably strongest on the region of ALT-2 encoding the signal peptide of L. loa and was elevated in the variable acidic domain of L. loa and W. bancrofti. Phylogenetic analysis indicated that the ALT-2 consensus sequences formed three clades: the first consisting of B. malayi, the second consisting of W. bancrofti, and the third containing both O. volvulus and L. loa. ALT-2 selection was therefore not predictable by phylogeny or pathology, as the two species parasitizing the eye were selected differently, as were the two species parasitizing the lymphatic system. The most immunogenic regions of L. loa and W. bancrofti ALT-2 sequence as modeled by antigenicity prediction analysis did not correspond with elevated levels of diversifying selection, and were not selected differently than predicted antigenic epitopes in B. malayi and O. volvulus. Measurements of ALT-2 evolvability made by χ2 analysis between alleles that were stable (O. volvulus and B. malayi) and those that were under diversifying selection (W. bancrofti and L. loa) indicated significant (P<0

  13. The ASCUS/LSIL Triage Study for Cervical Cancer (ALTS) | Division of Cancer Prevention

    Cancer.gov

    ALTS was a clinical trial to find the best way to help women and their doctors decide what to do about the mildly abnormal and very common Pap test results known as ASCUS and LSIL. | ALTS was a clinical trial to find the best way to help women and their doctors decide what to do about the mildly abnormal and very common Pap test results known as ASCUS and LSIL.

  14. AltTrans: transcript pattern variants annotated for both alternative splicing and alternative polyadenylation.

    PubMed

    Le Texier, Vincent; Riethoven, Jean-Jack; Kumanduri, Vasudev; Gopalakrishnan, Chellappa; Lopez, Fabrice; Gautheret, Daniel; Thanaraj, Thangavel Alphonse

    2006-03-23

    The three major mechanisms that regulate transcript formation involve the selection of alternative sites for transcription start (TS), splicing, and polyadenylation. Currently there are efforts that collect data & annotation individually for each of these variants. It is important to take an integrated view of these data sets and to derive a data set of alternate transcripts along with consolidated annotation. We have been developing in the past computational pipelines that generate value-added data at genome-scale on individual variant types; these include AltSplice on splicing and AltPAS on polyadenylation. We now extend these pipelines and integrate the resultant data sets to facilitate an integrated view of the contributions from splicing and polyadenylation in the formation of transcript variants. The AltSplice pipeline examines gene-transcript alignments and delineates alternative splice events and splice patterns; this pipeline is extended as AltTrans to delineate isoform transcript patterns for each of which both introns/exons and 'terminating' polyA site are delineated; EST/mRNA sequences that qualify the transcript pattern confirm both the underlying splicing and polyadenylation. The AltPAS pipeline examines gene-transcript alignments and delineates all potential polyA sites irrespective of underlying splicing patterns. Resultant polyA sites from both AltTrans and AltPAS are merged. The generated database reports data on alternative splicing, alternative polyadenylation and the resultant alternate transcript patterns; the basal data is annotated for various biological features. The data (named as integrated AltTrans data) generated for both the organisms of human and mouse is made available through the Alternate Transcript Diversity web site at http://www.ebi.ac.uk/atd/. The reported data set presents alternate transcript patterns that are annotated for both alternative splicing and alternative polyadenylation. Results based on current transcriptome data

  15. AltTrans: Transcript pattern variants annotated for both alternative splicing and alternative polyadenylation

    PubMed Central

    Le Texier, Vincent; Riethoven, Jean-Jack; Kumanduri, Vasudev; Gopalakrishnan, Chellappa; Lopez, Fabrice; Gautheret, Daniel; Thanaraj, Thangavel Alphonse

    2006-01-01

    Background The three major mechanisms that regulate transcript formation involve the selection of alternative sites for transcription start (TS), splicing, and polyadenylation. Currently there are efforts that collect data & annotation individually for each of these variants. It is important to take an integrated view of these data sets and to derive a data set of alternate transcripts along with consolidated annotation. We have been developing in the past computational pipelines that generate value-added data at genome-scale on individual variant types; these include AltSplice on splicing and AltPAS on polyadenylation. We now extend these pipelines and integrate the resultant data sets to facilitate an integrated view of the contributions from splicing and polyadenylation in the formation of transcript variants. Description The AltSplice pipeline examines gene-transcript alignments and delineates alternative splice events and splice patterns; this pipeline is extended as AltTrans to delineate isoform transcript patterns for each of which both introns/exons and 'terminating' polyA site are delineated; EST/mRNA sequences that qualify the transcript pattern confirm both the underlying splicing and polyadenylation. The AltPAS pipeline examines gene-transcript alignments and delineates all potential polyA sites irrespective of underlying splicing patterns. Resultant polyA sites from both AltTrans and AltPAS are merged. The generated database reports data on alternative splicing, alternative polyadenylation and the resultant alternate transcript patterns; the basal data is annotated for various biological features. The data (named as integrated AltTrans data) generated for both the organisms of human and mouse is made available through the Alternate Transcript Diversity web site at . Conclusion The reported data set presents alternate transcript patterns that are annotated for both alternative splicing and alternative polyadenylation. Results based on current

  16. D-Amino acid dipeptide production utilizing D-alanine-D-alanine ligases with novel substrate specificity.

    PubMed

    Sato, Masaru; Kirimura, Kohtaro; Kino, Kuniki

    2005-06-01

    D-Alanine-D-alanine ligase (Ddl) is an important enzyme in the synthesis of bacterial peptidoglycan. The genes encoding Ddls from Escherichia coli K12 (EcDdlB), Oceanobacillus iheyensis JCM 11309 (OiDdl), Synechocystis sp. PCC 6803 (SsDdl) and Thermotoga maritima ATCC 43589 (TmDdl), the genomic DNA sequences of which have been determined, were cloned and the substrate specificities of these recombinant Ddls were investigated. Although OiDdl had a high substrate specificity for D-alanine; EcDdlB, SsDdl and TmDdl showed broad substrate specificities for D-serine, D-threonine, D-cysteine and glycine, in addition to D-alanine. Four D-amino acid dipeptides were produced using EcDdlB, and D-amino acid homo-dipeptides were successfully produced at high yields except for D-threonyl-D-threonine.

  17. A role for monoubiquitinated FANCD2 at telomeres in ALT cells.

    PubMed

    Fan, Qiang; Zhang, Fan; Barrett, Briana; Ren, Keqin; Andreassen, Paul R

    2009-04-01

    Both Fanconi anemia (FA) and telomere dysfunction are associated with chromosome instability and an increased risk of cancer. Because of these similarities, we have investigated whether there is a relationship between the FA protein, FANCD2 and telomeres. We find that FANCD2 nuclear foci colocalize with telomeres and PML bodies in immortalized telomerase-negative cells. These cells maintain telomeres by alternative lengthening of telomeres (ALT). In contrast, FANCD2 does not colocalize with telomeres or PML bodies in cells which express telomerase. Using a siRNA approach we find that FANCA and FANCL, which are components of the FA nuclear core complex, regulate FANCD2 monoubiquitination and the telomeric localization of FANCD2 in ALT cells. Transient depletion of FANCD2, or FANCA, results in a dramatic loss of detectable telomeres in ALT cells but not in telomerase-expressing cells. Furthermore, telomere loss following depletion of these proteins in ALT cells is associated with decreased homologous recombination between telomeres (T-SCE). Thus, the FA pathway has a novel function in ALT telomere maintenance related to DNA repair. ALT telomere maintenance is therefore one mechanism by which monoubiquitinated FANCD2 may promote genetic stability.

  18. Determination of Alt a 1 (Alternaria alternata) in poultry farms and a sawmill using ELISA.

    PubMed

    Prester, Ljerka; Macan, Jelena

    2010-03-01

    Farm and sawmill workers are exposed to high levels of allergenic fungi, such as Alternaria alternata, which are associated with respiratory diseases and asthma. The aim of this study was to measure the concentration of Alt a 1, a major allergen of A. alternata, in indoor dust samples collected in poultry farms and a sawmill using a monoclonal antibody-based enzyme immunoassay. A total of 45 dust samples were collected in poultry farms (30) and the sawmill (15) in Zagreb County (Croatia). The Alt a 1 allergen was detected in all dust samples (100%) collected in three poultry farms. The levels of Alt a 1 were in the range of 0.1-14 microg/g, and the median value was 0.37 microg/g. About 86% of dust samples contained Alt a 1 in the range of 0.1-1.0 microg/g. In the sawmill, no detectable level of Alt a 1 was found (limit of detection =0.12 microg/g). This study has shown that occupational exposure to Alt a 1 allergen in poultry farms deserves monitoring.

  19. Noncovalent and covalent functionalization of a (5, 0) single-walled carbon nanotube with alanine and alanine radicals.

    PubMed

    Rajarajeswari, Muthusivarajan; Iyakutti, Kombiah; Kawazoe, Yoshiyuki

    2012-02-01

    We have systematically investigated the noncovalent and covalent adsorption of alanine and alanine radicals, respectively, onto a (5, 0) single-walled carbon nanotube using first-principles calculation. It was found that XH···π (X = N, O, C) interactions play a crucial role in the non-ovalent adsorption and that the functional group close to the carbon nanotube exhibits a significant influence on the binding strength. Noncovalent functionalization of the carbon nanotube with alanine enhances the conductivity of the metallic (5, 0) nanotube. In the covalent adsorption of each alanine radical onto a carbon nanotube, the binding energy depends on the adsorption site on CNT and the electronegative atom that binds with the CNT. The strongest complex is formed when the alanine radical interacts with a (5, 0) carbon nanotube through the amine group. In some cases, the covalent interaction of the alanine radical introduces a half-filled band at the Fermi level due to the local sp (3) hybridization, which modifies the conductivity of the tube.

  20. 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.

  1. The polyproline II conformation in short alanine peptides is noncooperative.

    PubMed

    Chen, Kang; Liu, Zhigang; Kallenbach, Neville R

    2004-10-26

    The finding that short alanine peptides possess a high fraction of polyproline II (PII) structure (Phi=-75 degrees, Psi=+145 degrees ) at low temperature has broad implications for unfolded states of proteins. An important question concerns whether or not this structure is locally determined or cooperative. We have monitored the conformation of alanine in a series of model peptides AcGGAnGGNH2 (n=1-3) over a temperature range from -10 degrees C to +80 degrees C. Use of 15N-labeled alanine substitutions makes it possible to measure 3JalphaN coupling constants accurately over the full temperature range. Based on a 1D next-neighbor model, the cooperative parameter sigma of PII nucleation is evaluated from the coupling constant data. The finding that sigma is close to unity (1 +/- 0.2) indicates a noncooperative role for alanine in PII structure formation, consistent with statistical surveys of the Protein Data Bank that suggest that most PII structure occurs in isolated residues. Lack of cooperativity in these models implies that hydration effects that influence PII conformation in water are highly localized. Using a nuclear Overhauser effect ratio strategy to define the alanine Psi angle, we estimate that, at 40 degrees C, the time-averaged alanine conformation (Phi=-80 degrees, Psi=+170 degrees ) deviates from canonical PII structure, indicating that PII melts at high temperature. Thus, the high-temperature state of short alanine peptides seems to be an unfolded ensemble with higher distribution in the extended beta structure basin, but not a coil.

  2. 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.

  3. The effect of 1g of acetaminophen twice daily for 12 weeks on alanine transaminase levels--A randomized placebo-controlled trial.

    PubMed

    Ioannides, Sally J; Siebers, Robert; Perrin, Kyle; Weatherall, Mark; Crane, Julian; Travers, Justin; Shirtcliffe, Philippa; Beasley, Richard

    2015-07-01

    Acetaminophen is often used on a regular, daily basis for the treatment of chronic pain; however, the safety of regular acetaminophen is still debated. This study determined whether 12 weeks of treatment with acetaminophen at half the maximum recommended daily dose causes an increase in alanine transaminase (ALT) in healthy adults participating in a clinical trial of the effect of acetaminophen on asthma control and severity. 94 healthy adults aged 18-65 years with mild to moderate asthma and with no history of previous liver dysfunction and an ALT within 1.5 times the upper limit of normal at baseline participated in a randomized, double-blind, placebo-controlled, parallel-group, clinical trial of 1g of acetaminophen twice daily or placebo twice daily for 12 weeks. Liver function monitoring was undertaken at baseline, weeks 2, 4, 6 and 12. The primary outcome variable was mean ALT levels at week 12 compared to baseline in the acetaminophen group versus placebo group. 94 participants were randomized and commenced study treatment. One participant in each treatment group was withdrawn due to an increase in ALT to greater than three times the upper limit of normal. Mean ALT at week 12 was 25.4I U/L (SD 9.7) in the acetaminophen group (N=31) and 19.0 IU/L (SD 6.0) in the placebo group (N=54). After controlling for baseline this represented a statistically significant difference of 3.6 IU/L (95% CI 1.3 to 6.0, P=0.003). There was no progressive increase in ALT demonstrated throughout the trial. Regular, daily use of acetaminophen at half the maximum recommended daily dose for 12 weeks in a healthy adult population is associated with a small elevation in mean ALT of no probable clinical significance. Further assessment of the effects on liver function of the maximum recommended dose of acetaminophen is required. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  4. Specificity of aspartate aminotransferases from leguminous plants for 4-substituted glutamic acids.

    PubMed

    Winter, H C; Dekker, E E

    1989-04-01

    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 V(m)/K(m)) 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.

  5. 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

  6. 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.

  7. Effect of adrenergic agonists and antagonists on alanine amino transferase, fructose-1:6-bisphosphatase and glucose production in hepatocytes.

    PubMed

    Begum, N A; Datta, A G

    1992-08-18

    Using rat hepatocytes we confirmed our previous results that glucagon and beta-adrenergic agonists increased the enzyme activity of alanine aminotransferase (AAT) and propranolol abolished their effects. Only the enzyme activity was measured and other parameters like quantity of the enzyme or activation due to modification were not looked for. As in perfusion experiment phenylephrine and phenoxybenzamine (alpha-agonist and alpha-antagonist respectively) also alpha-antagonist respectively) also increased the AAT activity in isolated rat hepatocytes and propranolol reversed these effects. The additive effect of glucagon and phenoxybenzamine on AAT was also persistent in hepatocyte system. Fructose-1:6-bisphosphatase (Fru-P2-ase), another key enzyme in gluconeogenic pathway, was elevated by glucagon and other beta-adrenergic agonists both in liver perfusion and isolated hepatocyte experiments and was brought back to the normal level by propranolol. In this case also only the enzyme activity was measured and no other parameters were looked for. Unlike AAT this enzyme was not stimulated by phenylephrine or phenoxybenzamine. But AAT and Fru-P2-ase activities were increased significantly by adenylate cyclase activators like fluoride or forskolin. Thus, it appears that the regulation of fru-P2-ase by glucagon is purely a b-receptor mediated process whereas AAT activation shows a mixed type of regulation where some well known alpha-agonist and antagonists are behaving as beta-agonists. Results further indicate the presence of phosphodiesterase in hepatocyte membrane which was stimulated by glucagon and brought back to the normal level by propranolol. The different adrenergic compounds stated above, not only modified the activity of the above two enzymes but also stimulated glucose production by hepatocytes from alanine which was in turn abolished by propranolol as well as amino oxyacetate (AOA), a highly specified inhibitor of AAT. This confirm the participation of AAT in

  8. Biochemical properties and crystal structure of a β-phenylalanine aminotransferase from Variovorax paradoxus.

    PubMed

    Crismaru, Ciprian G; Wybenga, Gjalt G; Szymanski, Wiktor; Wijma, Hein J; Wu, Bian; Bartsch, Sebastian; de Wildeman, Stefaan; Poelarends, Gerrit J; Feringa, Ben L; Dijkstra, Bauke W; Janssen, Dick B

    2013-01-01

    By selective enrichment, we isolated a bacterium that can use β-phenylalanine as a sole nitrogen source. It was identified by 16S rRNA gene sequencing as a strain of Variovorax paradoxus. Enzyme assays revealed an aminotransferase activity. Partial genome sequencing and screening of a cosmid DNA library resulted in the identification of a 1,302-bp aminotransferase gene, which encodes a 46,416-Da protein. The gene was cloned and overexpressed in Escherichia coli. The recombinant enzyme was purified and showed a specific activity of 17.5 U mg(-1) for (S)-β-phenylalanine at 30°C and 33 U mg(-1) at the optimum temperature of 55°C. The β-specific aminotransferase exhibits a broad substrate range, accepting ortho-, meta-, and para-substituted β-phenylalanine derivatives as amino donors and 2-oxoglutarate and pyruvate as amino acceptors. The enzyme is highly enantioselective toward (S)-β-phenylalanine (enantioselectivity [E], >100) and derivatives thereof with different substituents on the phenyl ring, allowing the kinetic resolution of various racemic β-amino acids to yield (R)-β-amino acids with >95% enantiomeric excess (ee). The crystal structures of the holoenzyme and of the enzyme in complex with the inhibitor 2-aminooxyacetate revealed structural similarity to the β-phenylalanine aminotransferase from Mesorhizobium sp. strain LUK. The crystal structure was used to rationalize the stereo- and regioselectivity of V. paradoxus aminotransferase and to define a sequence motif with which new aromatic β-amino acid-converting aminotransferases may be identified.

  9. Tailcone on orbiter altitude attainable at the maximum ALT interface airspeed

    NASA Technical Reports Server (NTRS)

    Glenn, G. M.

    1977-01-01

    A preflight analysis performed for verification of the ALT mated vehicle incidence angle which maximizes the post separation altitude attainment by the orbiter at the maximum approach and landing test (ALT) interface airspeed (300 KEAS) is discussed. In the analysis, altitude versus airspeed profiles are generated for each of the three incidence angles that include and bound the recommended incidence angle for both the forward and the aft cg tailcone on orbiter configurations. Results show that the recommended incidence angles maximize the orbiter post separation altitude attainable within an acceptable tradeoff between separation clearance capability and orbiter structural constraints. Within constraints, the incidence angle that maximizes the orbiter altitude at the maximum ALT interface airspeed for both the forward and aft cg orbiter tailcone on configurations is 6.0 deg. The requirement for a parametric analysis of orbiter altitude attainable at the maximum ALT interface airspeed is stated along with the specifications, assumptions, and analytical approach used to determine orbiter altitude attainable at the maximum ALT interface airspeed.

  10. Analysis of the survivability of the shuttle (ALT) fault-tolerant avionics system

    NASA Technical Reports Server (NTRS)

    1976-01-01

    An extension of the Complementary-Analytic-Simulative Technique (CAST) is presented which is applicable to the Shuttle Data Processing Subsystem (DPS). A two step process was used. The first step provides models, both analytic and simulative, for analysis of the Approach-Landing Test (ALT) configuration. The ALT modeling and analysis are presented. Since CAST had already been shown to be multicomputer systems, the emphasis was placed on extending the CAST concept so it is applicable to computer systems including the multiplicity of input and output devices found in a real-time control system application. The DPS mission-critical survivability for a six-hour mission was determined to be 0.999863 for the Shuttle ALT baseline configuration. Thus it can be said that for ALT, the survivability is adequate. However, the fact that orbiting missions of up to 30 days are planned illustrates the necessity of extending the ALT work to be applicable to OFT and actual mission scenarios. The above analysis led to the evaluation of three selected options which identified two areas of possible improvement. These improvements would result from use of a recovery technique which combines roll ahead with memory copy, and increased TACAN fault detectability.

  11. AST/ALT ratio is not useful in predicting the degree of fibrosis in chronic viral hepatitis patients.

    PubMed

    Eminler, Ahmet Tarik; Ayyildiz, Talat; Irak, Kader; Kiyici, Murat; Gurel, Selim; Dolar, Enver; Gulten, Macit; Nak, Selim G

    2015-12-01

    Noninvasive tests are primarily used for staging hepatic fibrosis in patients with chronic liver disease. In clinical practice, serum aminotransferase levels, coagulation parameters, and platelet count have been used to predict whether or not a patient has cirrhosis. In addition, several studies have evaluated the accuracy of combinations (or ratios) of these measures. The present study aimed to investigate the relationship between five noninvasive models [AST/ALT ratio (AAR), aspartate aminotransferase to platelet ratio index (APRI), Bonacini cirrhosis discriminant score (CDS), age-platelet index (APind), and King's score] and the degree of hepatic fibrosis as determined by biopsy in patients with chronic hepatitis B and C. A total of 380 patients with viral hepatitis (237 with chronic hepatitis B and 143 with chronic hepatitis C) who were seen at our clinic between January 2005 and January 2011 were retrospectively analyzed. The degree of fibrosis was determined using the Ishak score. Patients with a fibrosis score of 0-2 were considered to have low fibrosis and those with a score between 3 and 6 were considered to have high fibrosis. Five noninvasive models were compared between the groups with low and high fibrosis. There were statistically significant differences between the hepatitis B and C patients with high and low fibrosis with respect to APind (4.49±2.35 vs. 2.41±1.84; P<0.001 in hepatitis B and 4.83±2.25 vs. 2.92±1.88; P<0.001 in hepatitis C), APRI (1.00±1.17 vs. 0.47±0.39; P<0.001 in hepatitis B and 1.01±1.01 vs. 0.41±0.29; P<0.001 in hepatitis C), CDS (4.53±1.90 vs. 3.58±1.30; P<0.001 in hepatitis B and 4.71±2.03 vs. 3.42±1.49; P<0.05 in hepatitis C), and King's score (24.31±3.14 vs. 7.65±6.70; P<0.001 in hepatitis B and 24.82±2.55 vs. 8.33±7.29; P<0.001 in hepatitis C). There were no significant differences in the AAR between the hepatitis B and C patients with high and low fibrosis (0.78±0.31 vs. 0.74±0.34; P=0.082 in hepatitis B

  12. Post-Irradiation Study of the Alanine Dosimeter

    PubMed Central

    Desrosiers, Marc F.

    2014-01-01

    Post-irradiation stability of high-dose dosimeters has traditionally been an important measurement influence quantity. Though the exceptional stability of the alanine dosimeter response with time has rendered this factor a non-issue for routine work, the archival quality of the alanine dosimeter has not been characterized. Here the alanine pellet dosimeter response is measured up to seven years post-irradiation for a range of absorbed doses. This long-term study is accompanied by an examination of the environmental influence quantities (e.g., ambient light) on the relatively short-term (3–4 month) stability of both pellet and film commercial dosimeters. Both dosimeter types demonstrated exceptional stability in the short term and proved to be relatively insensitive to common influence quantities. The long-term data revealed a complex dose-dependent response trend. PMID:26601033

  13. [Effects of ß-alanine supplementation on athletic performance].

    PubMed

    Domínguez, Raúl; Hernández Lougedo, Juan; Maté-Muñoz, José Luis; Garnacho-Castaño, Manuel Vicente

    2014-10-06

    Carnosine, dipeptide formed by amino acids ß-alanine and L-histidine, has important physiological functions among which its antioxidant and related memory and learning. However, in connection with the exercise, the most important functions would be associated with muscle contractility, improving calcium sensitivity in muscle fibers, and the regulatory function of pH. Thus, it is proposed that carnosine is the major intracellular buffer, but could contribute to 7-10% in buffer or buffer capacity. Since carnosine synthesis seems to be limited by the availability of ß-alanine supplementation with this compound has been gaining increasing popularity among the athlete population. Therefore, the objective of this study literature review was to examine all those research works have shown the effect of ß-alanine supplementation on athletic performance. Moreover, it also has attempted to establish a specific dosage that maximizing the potential benefits, minimize paresthesia, the main side effect presented in response to supplementation.

  14. 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.

  15. Involvement of a branched-chain aminotransferase in production of volatile sulfur compounds in Yarrowia lipolytica.

    PubMed

    Bondar, Daniela Cernat; Beckerich, Jean-Marie; Bonnarme, Pascal

    2005-08-01

    The enzymatic degradation of L-methionine and the subsequent formation of volatile sulfur compounds (VSCs) are essential for the development of the typical flavor in cheese. In the yeast Yarrowia lipolytica, the degradation of L-methionine was accompanied by the formation of the transamination product 4-methylthio-2-oxobutyric acid. A branched-chain aminotransferase gene (YlBCA1) of Y. lipolytica was amplified, and the L-methionine-degrading activity and the aminotransferase activity were measured in a genetically modified strain and compared to those of the parental strain. Our work shows that L-methionine degradation via transamination is involved in formation of VSCs in Y. lipolytica.

  16. 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.

  17. On the existence of ``l-threonine formate'', ``l-alanine lithium chloride'' and ``bis l-alanine lithium chloride'' crystals

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. M.; Ghazaryan, V. V.; Fleck, M.

    2013-03-01

    We argue that the recently reported crystals "L-threonine formate" as well as "L-alanine lithium chloride" and "bis L-alanine lithium chloride" actually are the well-known crystals L-threonine and L-alanine, respectively.

  18. Atomic Layer Deposition of L-Alanine Polypeptide

    SciTech Connect

    Fu, Yaqin; Li, Binsong; Jiang, Ying-Bing; Dunphy, Darren R.; Tsai, Andy; Tam, Siu-Yue; Fan, Hongyou Y.; Zhang, Hongxia; Rogers, David; Rempe, Susan; Atanassov, Plamen; Cecchi, Joseph L.; Brinker, C. Jeffrey

    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.

  19. β-Alanine as an Ethylene Precursor. Investigations Towards Preparation, and Properties, of a Soluble Enzyme System From a Subcellular Particulate Fraction of Bean Cotyledons 1

    PubMed Central

    Stinson, Robert A.; Spencer, Mary

    1969-01-01

    A method is described for the preparation, from a subcellular particulate fraction of wax bean cotyledons, of a soluble enzyme system that is capable of converting β-alanine to ethylene. In the presence of ATP, CoA, thiamine pyrophosphate, MgSO4, and pyridoxal phosphate, ethylene production is maximum at a 0.5 mm concentration of β-alanine. The system exhibits a pH optimum at 7.0 but when the pH is raised above 8, evolution of the volatile again increases and continues to do so up to pH 12. The enzyme system is stimulated by either NADPH or NADH; the concentration of NADPH necessary to obtain maximum activity is twice that of NADH. The requirement for a reducing agent is in agreement with the proposal that malonate semialdehyde, formed by an aminotransferase reaction from β-alanine, is reduced to β-hydroxypropionate. Both malonate semialdehyde and β-hydroxypropionate are better stimulators of production of the volatile in the soluble system than is β-alanine, and β-hydroxypropionate is a better stimulator than malonate semialdehyde. This system is also able to incorporate tritium from tritiated water into ethylene; this supports the proposal that ethylene is formed by the decarboxylation of acrylate, the latter being formed from β-hydroxypropionate. Experiments with both cold and labeled malonate suggest that this compound stimulates ethylene production by acting as an end product inhibitor that prevents the loss of malonate semialdehyde from the pathway. Malonate does not appear to serve as a precursor. Addition of cytoplasmic enzymes to the `soluble system' (prepared from particulate enzymes) results in a considerable boost in ethylene production, but the specific activity (mμ1 / mg protein) is lowered from that of the particulate enzymes alone. PMID:16657194

  20. Environmental Stress Induces Trinucleotide Repeat Mutagenesis in Human Cells by Alt-Nonhomologous End Joining Repair.

    PubMed

    Chatterjee, Nimrat; Lin, Yunfu; Yotnda, Patricia; Wilson, John H

    2016-07-31

    Multiple pathways modulate the dynamic mutability of trinucleotide repeats (TNRs), which are implicated in neurodegenerative disease and evolution. Recently, we reported that environmental stresses induce TNR mutagenesis via stress responses and rereplication, with more than 50% of mutants carrying deletions or insertions-molecular signatures of DNA double-strand break repair. We now show that knockdown of alt-nonhomologous end joining (alt-NHEJ) components-XRCC1, LIG3, and PARP1-suppresses stress-induced TNR mutagenesis, in contrast to the components of homologous recombination and NHEJ, which have no effect. Thus, alt-NHEJ, which contributes to genetic mutability in cancer cells, also plays a novel role in environmental stress-induced TNR mutagenesis. Published by Elsevier Ltd.

  1. Space shuttle engineering and operations support. Separation operational limits for ALT free flights 1 through 5

    NASA Technical Reports Server (NTRS)

    Seale, R. H.

    1977-01-01

    The orbiter/SCA separation operational limits for the current target conditions of ALT free flights 1 through 5 are analyzed. The separation operational limits are used to verify that no separation design constraints are violated. The operational limits represent the acceptable dispersions in attainment of separation target conditions which assure safe separation. Safe separation is based on satisfying all specified separation design criteria except orbiter altitude at ALT interface airspeed. Separation operational limits are defined for each of the five orbiter tailcones on ALT free flight missions based upon preflight aerodynamics. The effect of carrier pilot steering compensation due to off-nominal flight conditions is determined to be within the separation operational limits.

  2. Alt a 1 from Alternaria interacts with PR5 thaumatin-like proteins.

    PubMed

    Gómez-Casado, Cristina; Murua-García, Amaya; Garrido-Arandia, María; González-Melendi, Pablo; Sánchez-Monge, Rosa; Barber, Domingo; Pacios, Luis F; Díaz-Perales, Araceli

    2014-05-02

    Alt a 1 is a protein found in Alternaria alternata spores related to virulence and pathogenicity and considered to be responsible for chronic asthma in children. We found that spores of Alternaria inoculated on the outer surface of kiwifruits did not develop hyphae. Nevertheless, the expression of Alt a 1 gene was upregulated, and the protein was detected in the pulp where it co-localized with kiwi PR5. Pull-down assays demonstrated experimentally that the two proteins interact in such a way that Alt a 1 inhibits the enzymatic activity of PR5. These results are relevant not only for plant defense, but also for human health as patients with chronic asthma could suffer from an allergic reaction when they eat fruit contaminated with Alternaria. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  3. Optimization of Alt-PSM structure for 45nm node ArF immersion lithography

    NASA Astrophysics Data System (ADS)

    Adachi, Takashi; Mesuda, Kei; Toyama, Nobuhito; Morikawa, Yasutaka; Mohri, Hiroshi; Hayashi, Naoya

    2005-11-01

    Alternating Aperture Phase Shifting Mask (Alt-APSM) has been expected as one of the practical techniques for 45nm node ArF lithography. We have already discussed and proposed the Single trench with undercut (UC) and bias structure is the primary candidate for 65nm node Alt-APSM structure. In fact, we have selected this structure as a standard in production for 65nm node Alt-PSM. For the 45nm node, according to the design shrinkage, mask rule such as MRC which specify minimum chrome CD between 0 and pi degree apertures and etc. is getting tighter. So, we need to consider about single trench with no undercut and bias structure. Such two types of structure are the candidates for 45nm node Alt-APSM. Exposure conditions will be considered as 0.9 or higher NA and the immersion technology as well. In this work, we will discuss about 45nm node Alt-PSM structure in terms of lithographic performance by using 3D rigorous optical simulation software. Two types of structure, single trench with UC and bias, and single trench with No UC and bias are compared. We examined the following items to find optimum Alt-PSM structure, 0/pi space bias to minimize CD difference at the wafer, quartz depth to optimize effective phase and optical proximity correction (OPC) to adjust printed line CD in through pitch condition. Wafer printing performance will be evaluated by the stability of line CD and 0-pi CD difference, contrast, NILS, phase angles, MEEF, ED-window and gate position shift.

  4. 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.

  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. AltText: A Showcase of User Centred Design in the Netherlands

    NASA Astrophysics Data System (ADS)

    Asjes, Kathleen

    In the information processing chain many documents are produced that are inaccessible to the reading impaired. The altText project aims to increase the accessibility of this content by: a) raising awareness among content providers about content adaption; b) allowing content providers to deliver content in a way that suits the needs of the information receiver; c) developing an online service that converts written text into several accessible formats (Braille, synthetic speech, large print or DaisyXML). The name of this service is the altText conversion portal. The paper argues that user centred innovation will be crucial to the success of this project.

  7. Approach & Landing Test (ALT) - Shuttle Free-Flight (FF)-2 - New Release - DFRC, CA

    NASA Image and Video Library

    1977-09-13

    S77-28137 (13 Sept 1977) --- The Orbiter 101 "Enterprise" soars above the NASA 747 carrier aircraft during the second free flight of the Shuttle Approach and Landing Tests (ALTs) conducted on September 13, 1977 at Dryden Flight Research Center in Southern California. Astronauts Joe H. Engle, and Richard H. Truly were the crew of the "Enterprise." The ALT free flights are designed to verify Orbiter subsonic airworthiness, integrated systems operations and pilot-guided approach and landing capability and satisfying prerequisites to automatic flight control and navigation mode.

  8. [Regulation of key enzymes of L-alanine biosynthesis by Brevibacterium flavum producer strains].

    PubMed

    Melkonian, L O; Avetisova, G E; Ambartsumian, A A; Chakhalian, A Kh; Sagian, A S

    2013-01-01

    The mechanisms of L-alanine overproduction by Brevibacterium flavum producer strains were studied. It was shown that beta-CI-L-alanine is an inhibitor of some key enzymes involved in the synthesis of L-alanine, including alanine transaminase and valine-pyruvate transaminase. Two highly active B. flavum GL1 and GL1 8 producer strains, which are resistant to the inhibitory effect of beta-Cl-L-alanine, were obtained using a parental B. flavum AA5 producer strain, characterized by a reduced activity of alanine racemase (>or=98%). It was demonstrated that the increased L-alanine synthesis efficiency observed in the producer strains developed in this work is associated with the absence of inhibition of alanine transaminase by the end product of the biosynthesis reaction, as well as with the effect of derepression of both alanine transaminase and valine-pyruvate transaminase synthesis by the studied compound.

  9. Structure, expression, and function of kynurenine aminotransferases in human and rodent brains

    PubMed Central

    Han, Qian; Cai, Tao; Tagle, Danilo A.

    2010-01-01

    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 Iε. 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. PMID:19826765

  10. 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.

  11. 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

  12. A theoretical study of alanine dipeptide and analogs

    SciTech Connect

    Head-Gordon, T.; Head-Gordon, M.; Brooks, C. III; Pople, J. ); Frisch, M.J. )

    1989-01-01

    We Present a preliminary report on the conformational and energetic analysis of the molecule (S)-2-acetylamino-N-methylpropanamide (alanine dipeptide) and an analog molecule, (S)-{alpha}-formylaminopropanamide, using high-quality ab initio methods. Alanine dipeptide and its analogs are of interest since they incorporate many of the structural features found in proteins, such as intramolecular hydrogen bonds, conformational flexibility, and a variety of chemical functionality. One purpose of this study is to provide a useful benchmark calculation, MP2/6-31+G{sup **}//HF/6-31+G{sup *}, for a number of conformations of the alanine system. Based on the comparison of these benchmark calculations with lower-level basis sets, HF/3-21G was chosen to generate a fully relaxed {phi}, {psi} dihedral map. These calculations are the first of their kind on systems of this size. Features of the {phi},{psi} alanine dipeptide map that are discussed include the energetically accessible conformations and possible pathways for their interconversion. In addition, we illustrate the importance of fully optimized geometries and the proper evaluation of correlation energies,

  13. 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).

  14. 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.

  15. Beta-alanine supplementation, muscle carnosine and exercise performance.

    PubMed

    Blancquaert, Laura; Everaert, Inge; Derave, Wim

    2015-01-01

    The use of dietary supplements in sports is widespread as athletes are continuously searching for strategies to increase performance at the highest level. Beta-alanine is such a supplement that became increasingly popular during the past years. This review examines the available evidence regarding the optimization of supplementation, the link between beta-alanine and exercise performance and the underlying ergogenic mechanism. It has been repeatedly demonstrated that chronic beta-alanine supplementation can augment intramuscular carnosine content. Yet, the factors that determine the loading process, as well as the mechanism by which this has an ergogenic effect, are still debated. On the basis of its biochemical properties, several functions are ascribed to carnosine, of which intramuscular pH buffer and calcium regulator are the most cited ones. In addition, carnosine has antiglycation and antioxidant properties, suggesting it could have a therapeutic potential. On the basis of the millimolar presence of carnosine in mammalian muscles, it must play a critical role in skeletal muscle physiology. The recent number of studies shows that this is related to an improved exercise homeostasis and excitation-contraction coupling. Recent developments have led to the optimization of the beta-alanine supplementation strategies to elevate muscle carnosine content, which are helpful in its application in sports and to potential future therapeutic applications.

  16. Computational alanine scanning with linear scaling semiempirical quantum mechanical methods.

    PubMed

    Diller, David J; Humblet, Christine; Zhang, Xiaohua; Westerhoff, Lance M

    2010-08-01

    Alanine scanning is a powerful experimental tool for understanding the key interactions in protein-protein interfaces. Linear scaling semiempirical quantum mechanical calculations are now sufficiently fast and robust to allow meaningful calculations on large systems such as proteins, RNA and DNA. In particular, they have proven useful in understanding protein-ligand interactions. Here we ask the question: can these linear scaling quantum mechanical methods developed for protein-ligand scoring be useful for computational alanine scanning? To answer this question, we assembled 15 protein-protein complexes with available crystal structures and sufficient alanine scanning data. In all, the data set contains Delta Delta Gs for 400 single point alanine mutations of these 15 complexes. We show that with only one adjusted parameter the quantum mechanics-based methods outperform both buried accessible surface area and a potential of mean force and compare favorably to a variety of published empirical methods. Finally, we closely examined the outliers in the data set and discuss some of the challenges that arise from this examination.

  17. Alanine flux in obese and healthy humans as evaluated by /sup 15/N- and /sup 2/H/sub 3/-labeled alanines

    SciTech Connect

    Hoffer, L.J.; Yang, R.D.; Matthews, D.E.; Bistrian, B.R.; Bier, D.M.; Young, V.R.

    1988-10-01

    Estimates of plasma alanine flux as measured in humans using L-(/sup 15/N)-alanine or L-(3,3,3-/sup 2/H/sub 3/)alanine were compared by simultaneous intravenous infusion of both tracers. Plasma isotope enrichments were measured by chemical ionization gas chromatography-mass spectrometry. In 16 obese women before and during a hypocaloric diet and in 4 normal men in the postabsorptive and fed states, the fluxes were highly correlated (r2 = 0.93) although plasma alanine flux with the /sup 2/H tracer was two to three times greater than that obtained with (/sup 15/N)alanine. The fluxes decreased with the hypocaloric diet in obese subjects and increased during the fed state in healthy adults. Thus, although the estimates of alanine flux differed according to the tracer used, both appear to give equivalent information about changes in alanine kinetics induced by the nutritional conditions examined.

  18. Crystal structure of Trypanosoma cruzi tyrosine aminotransferase: substrate specificity is influenced by cofactor binding mode.

    PubMed Central

    Blankenfeldt, W.; Nowicki, C.; Montemartini-Kalisz, M.; Kalisz, H. M.; Hecht, H. J.

    1999-01-01

    The crystal structure of tyrosine aminotransferase (TAT) from the parasitic protozoan Trypanosoma cruzi, which belongs to the aminotransferase subfamily Igamma, has been determined at 2.5 A resolution with the R-value R = 15.1%. T. cruzi TAT shares less than 15% sequence identity with aminotransferases of subfamily Ialpha but shows only two larger topological differences to the aspartate aminotransferases (AspATs). First, TAT contains a loop protruding from the enzyme surface in the larger cofactor-binding domain, where the AspATs have a kinked alpha-helix. Second, in the smaller substrate-binding domain, TAT has a four-stranded antiparallel beta-sheet instead of the two-stranded beta-sheet in the AspATs. The position of the aromatic ring of the pyridoxal-5'-phosphate cofactor is very similar to the AspATs but the phosphate group, in contrast, is closer to the substrate-binding site with one of its oxygen atoms pointing toward the substrate. Differences in substrate specificities of T. cruzi TAT and subfamily Ialpha aminotransferases can be attributed by modeling of substrate complexes mainly to this different position of the cofactor-phosphate group. Absence of the arginine, which in the AspATs fixes the substrate side-chain carboxylate group by a salt bridge, contributes to the inability of T. cruzi TAT to transaminate acidic amino acids. The preference of TAT for tyrosine is probably related to the ability of Asn17 in TAT to form a hydrogen bond to the tyrosine side-chain hydroxyl group. PMID:10595543

  19. Isolation and characterization of a gene coding for a novel aspartate aminotransferase from Rhizobium meliloti.

    PubMed Central

    Alfano, J R; Kahn, M L

    1993-01-01

    Aspartate aminotransferase (AAT) is an important enzyme in aspartate catabolism and biosynthesis and, by converting tricarboxylic acid cycle intermediates to amino acids, AAT is also significant in linking carbon metabolism with nitrogen metabolism. To examine the role of AAT in symbiotic nitrogen fixation further, plasmids encoding three different aminotransferases from Rhizobium meliloti 104A14 were isolated by complementation of an Escherichia coli auxotroph that lacks three aminotransferases. pJA10 contained a gene, aatB, that coded for a previously undescribed AAT, AatB. pJA30 encoded an aromatic aminotransferase, TatA, that had significant AAT activity, and pJA20 encoded a branched-chain aminotransferase designated BatA. Genes for the latter two enzymes, tatA and batA, were previously isolated from R. meliloti. aatB is distinct from but hybridizes to aatA, which codes for AatA, a protein required for symbiotic nitrogen fixation. The DNA sequence of aatB contained an open reading frame that could encode a protein 410 amino acids long and with a monomer molecular mass of 45,100 Da. The amino acid sequence of aatB is unusual, and AatB appears to be a member of a newly described class of AATs. AatB expressed in E. coli has a Km for aspartate of 5.3 mM and a Km for 2-oxoglutarate of 0.87 mM. Its pH optimum is between 8.0 and 8.5. Mutations were constructed in aatB and tatA and transferred to the genome of R. meliloti 104A14. Both mutants were prototrophs and were able to carry out symbiotic nitrogen fixation. Images PMID:8320232

  20. 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.

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

    PubMed

    Wiyakrutta, S; Meevootisom, V

    1997-07-04

    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.

  2. [Reconstruction of soft tissue defect of the sole using an ALT flap].

    PubMed

    Kovács, István; Lóderer, Zoltán; Bognár, Gábor; Jánó, Zoltán; Németh, Róbert; Bognár, Gábor; Nagy, Attila

    2010-12-01

    Soft tissue defect of the sole is usually a quite challenging problem. In this case report the most frequently used reconstructive options of this problem are reviewed paying particular attention for the well applicable and reliable types. An ALT graft as a free flap to the sole offers a good possibility for coverage, which is resistant enough to mechanic strains.

  3. The Basis of Aluminum Tolerance Encoded by the Alt3 Locus of Rye

    USDA-ARS?s Scientific Manuscript database

    Aluminium (Al) toxicity, affecting around half of the world’s arable land, severely hinders the ability of crop plants to cope with drought and nutrient stresses by restricting root growth and function. Among the cultivated cereals, rye is the most Al tolerant. At the Alt3 Al tolerance locus on rye ...

  4. On the Trajectories of the Predetermined ALT Model: What Are We Really Modeling?

    ERIC Educational Resources Information Center

    Jongerling, Joran; Hamaker, Ellen L.

    2011-01-01

    This article shows that the mean and covariance structure of the predetermined autoregressive latent trajectory (ALT) model are very flexible. As a result, the shape of the modeled growth curve can be quite different from what one might expect at first glance. This is illustrated with several numerical examples that show that, for example, a…

  5. Crystal structures of d-alanine-d-alanine ligase from Xanthomonas oryzae pv. oryzae alone and in complex with nucleotides.

    PubMed

    Doan, Thanh Thi Ngoc; Kim, Jin-Kwang; Ngo, Ho-Phuong-Thuy; Tran, Huyen-Thi; Cha, Sun-Shin; Min Chung, Kyung; Huynh, Kim-Hung; Ahn, Yeh-Jin; Kang, Lin-Woo

    2014-03-01

    D-Alanine-D-alanine ligase (DDL) catalyzes the biosynthesis of d-alanyl-d-alanine, an essential bacterial peptidoglycan precursor, and is an important drug target for the development of antibacterials. We determined four different crystal structures of DDL from Xanthomonas oryzae pv. oryzae (Xoo) causing Bacteria Blight (BB), which include apo, ADP-bound, ATP-bound, and AMPPNP-bound structures at the resolution between 2.3 and 2.0 Å. Similarly with other DDLs, the active site of XoDDL is formed by three loops from three domains at the center of enzyme. Compared with d-alanyl-d-alanine and ATP-bound TtDDL structure, the γ-phosphate of ATP in XoDDL structure was shifted outside toward solution. We swapped the ω-loop (loop3) of XoDDL with those of Escherichia coli and Helicobacter pylori DDLs, and measured the enzymatic kinetics of wild-type XoDDL and two mutant XoDDLs with the swapped ω-loops. Results showed that the direct interactions between ω-loop and other two loops are essential for the active ATP conformation for D-ala-phosphate formation.

  6. An approximation of the Cioslowski-Mixon bond order indexes using the AlteQ approach

    NASA Astrophysics Data System (ADS)

    Salmina, Elena; Grishina, Maria A.; Potemkin, Vladimir A.

    2013-09-01

    Fast and reliable prediction of bond orders in organic systems based upon experimentally measured quantities can be performed using electron density features at bond critical points (J Am Chem Soc 105:5061-5068, 1983; J Phys Org Chem 16:133-141, 2003; Acta Cryst B 61:418-428, 2005; Acta Cryst B 63:142-150, 2007). These features are outcomes of low-temperature high-resolution X-ray diffraction experiments. However, a time-consuming procedure of gaining these quantities makes the prediction limited. In the present work we have employed an empirical approach AlteQ (J Comput Aided Mol Des 22:489-505, 2008) for evaluation of electron density properties. This approach uses a simple exponential function derived from comparison of electron density, gained from high-resolution X-ray crystallography, and distance to atomic nucleus what allows calculating density distribution in time-saving manner and gives results which are very close to experimental ones. As input data AlteQ accepts atomic coordinates of isolated molecules or molecular ensembles (for instance, protein-protein complexes or complexes of small molecules with proteins, etc.). Using AlteQ characteristics we have developed regression models predicting Cioslowski-Mixon bond order (CMBO) indexes (J Am Chem Soc 113(42):4142-4145, 1991). The models are characterized by high correlation coefficients lying in the range from 0.844 to 0.988 dependently on the type of covalent bond, thereby providing a bonding quantification that is in reasonable agreement with that obtained by orbital theory. Comparative analysis of CMBOs approximated using topological properties of AlteQ and experimental electron densities has shown that the models can be used for fast determination of bond orders directly from X-ray crystallography data and confirmed that AlteQ characteristics can replace experimental ones with satisfactory extent of accuracy.

  7. 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

  8. 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.

  9. Kinetic mechanism and inhibition of Mycobacterium tuberculosis D-alanine:D-alanine ligase by the antibiotic D-cycloserine.

    PubMed

    Prosser, Gareth A; de Carvalho, Luiz Pedro S

    2013-02-01

    D-cycloserine (DCS) is an antibiotic that is currently used in second-line treatment of tuberculosis. DCS is a structural analogue of D-alanine, and targets two enzymes involved in the cytosolic stages of peptidoglycan synthesis: alanine racemase (Alr) and D-alanine:D-alanine ligase (Ddl). The mechanisms of inhibition of DCS have been well-assessed using Alr and Ddl enzymes from various bacterial species, but little is known regarding the interactions of DCS with the mycobacterial orthologues of these enzymes. We have over-expressed and purified recombinant Mycobacterium tuberculosis Ddl (MtDdl; Rv2981c), and report a kinetic examination of the enzyme with both its native substrate and DCS. MtDdl is activated by K(+), follows an ordered ter ter mechanism and displays distinct affinities for D-Ala at each D-Ala binding site (K(m,D-Ala1) = 0.075 mm, K(m,D-Ala2) = 3.6 mm). ATP is the first substrate to bind and is necessary for subsequent binding of D-alanine or DCS. The pH dependence of MtDdl kinetic parameters indicate that general base chemistry is involved in the catalytic step. DCS was found to competitively inhibit D-Ala binding at both MtDdl D-Ala sites with equal affinity (K(i,DCS1) = 14 μm, K(i,DCS2) = 25 μm); however, each enzyme active site can only accommodate a single DCS molecule at a given time. The pH dependence of K(i,DCS2) revealed a loss of DCS binding affinity at high pH (pK(a) = 7.5), suggesting that DCS binds optimally in the zwitterionic form. The results of this study may assist in the design and development of novel Ddl-specific inhibitors for use as anti-mycobacterial agents.

  10. Acidic residues important for substrate binding and cofactor reactivity in eukaryotic ornithine decarboxylase identified by alanine scanning mutagenesis.

    PubMed

    Osterman, A L; Kinch, L N; Grishin, N V; Phillips, M A

    1995-05-19

    Ornithine decarboxylases from Trypanosoma brucei, mouse, and Leishmania donovani share strict specificity for three basic amino acids, ornithine, lysine, and arginine. To identify residues involved in this substrate specificity and/or in the reaction chemistry, six conserved acidic resides (Asp-88, Glu-94, Asp-233, Glu-274, Asp-361, and Asp-364) were mutated to alanine in the T. brucei enzyme. Each mutation causes a substantial loss in enzyme efficiency. Most notably, mutation of Asp-361 increases the Km for ornithine by 2000-fold, with little effect on kcat, suggesting that this residue is an important substrate binding determinant. Mutation of the only strictly conserved acidic residue, Glu-274, decreases kcat 50-fold; however, substitution of N-methylpyridoxal-5'-phosphate for pyridoxal-5'-phosphate as the cofactor in the reaction restores the kcat of E274A to wild-type levels. These data demonstrate that Glu-274 interacts with the protonated pyridine nitrogen of the cofactor to enhance the electron withdrawing capability of the ring, analogous to Asp-222 in aspartate aminotransferase (Onuffer, J. J., and Kirsch, J. F. (1994) Protein Eng. 7, 413-424). Eukaryotic ornithine decarboxylase is a homodimer with two shared active sites. Residues 88, 94, 233, and 274 are contributed to each active site from the same subunit as Lys-69, while residues 361 and 364 are part of the Cys-360 subunit.

  11. Clinical applications of alanine/electron spin resonance dosimetry.

    PubMed

    Baffa, Oswaldo; Kinoshita, Angela

    2014-05-01

    This paper discusses the clinical applications of electron spin resonance (ESR) dosimetry focusing on the ESR/alanine system. A review of few past studies in this area is presented offering a critical overview of the challenges and opportunities for extending this system into clinical applications. Alanine/ESR dosimetry fulfills many of the required properties for several clinical applications such as water-equivalent composition, independence of the sensitivity for the energy range used in therapy and high precision. Improvements in sensitivity and the development of minidosimeters coupled with the use of a spectrometer of higher microwave frequency expanded the possibilities for clinical applications to the new modalities of radiotherapy (intensity-modulated radiation therapy and radiosurgery) and to the detection of low doses such as those present in some radiological image procedures.

  12. Degradation of glycine and alanine on irradiated quartz.

    PubMed

    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.

  13. First principles investigation of L-alanine in terahertz region.

    PubMed

    Zheng, Zhuan-Ping; Fan, Wen-Hui

    2012-06-01

    Terahertz absorption spectrum (0.5-4.0 THz) of L-alanine in the solid phase was measured by terahertz time-domain spectroscopy at room temperature. Simulations utilizing gaseous-state and solid-state theory were performed to determine the origins of the observed vibrational features. Our calculations showed that the measured features in solid-state materials could be well understood by considering the crystal packing interactions in a solid-state density functional theory calculation. Furthermore, intermolecular vibrations of L-alanine are found to be the dominating contributions to these measured spectral features in the range of 0.5-4.0 THz, except that located at 3.11 THz.

  14. 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.

  15. Alanine, glutamate, and ammonia exchanges in acutely ischemic swine myocardium.

    PubMed

    Hacker, T A; Hall, J L; Stone, C K; Stanley, W C

    1992-01-01

    Coronary artery disease causes an increase in glutamate uptake and alanine output by the heart. We assessed the effects of acute myocardial ischemia on alanine and glutamate exchange and ammonia production in 10 anesthetized open-chest domestic swine (46.9 +/- 0.7 kg). Coronary blood flow was controlled through an extracorporal perfusion circuit. After a nonischemic control period (aerobic) the blood flow in the left anterior descending coronary artery was reduced by 60%. Arterial and anterior interventricular venous samples where drawn before and during 35 min of ischemia. Subendocardial blood flow, measured using radiolabeled microspheres, decreased from 1.27 +/- 0.16 to 0.25 +/- 0.09 (ml/g)/min, and left-ventricular wall-thickening fell to 47% of aerobic values. Ischemia resulted in a significant increase in the rate of glucose uptake (p less than 0.05) and a switch to net lactate production (p less than 0.01). Ischemia did not affect the rates of alanine output (-0.9 +/- 1.0 vs. -0.3 +/- 0.3 mumol/min) or glutamate uptake (-0.4 +/- 1.1 vs. 0.3 +/- 0.6 mumol/min), but did increase the venous-arterial difference for ammonia (-4.1 +/- 4.1 to 52.7 +/- 5.5 microM, p less than 0.0001) and the ammonia output (-0.33 +/- 0.24 to 1.34 +/- 0.14 mumol/min, p less than 0.0001). In conclusion, acute ischemia did not stimulate greater alanine output or glutamate uptake. However, acute ischemia did cause an increase in anaerobic glycolysis rate and ammonia output, which reflects a profound disruption in myocardial energy metabolism.

  16. Involvement of a Branched-Chain Aminotransferase in Production of Volatile Sulfur Compounds in Yarrowia lipolytica

    PubMed Central

    Cernat Bondar, Daniela; Beckerich, Jean-Marie; Bonnarme, Pascal

    2005-01-01

    The enzymatic degradation of l-methionine and the subsequent formation of volatile sulfur compounds (VSCs) are essential for the development of the typical flavor in cheese. In the yeast Yarrowia lipolytica, the degradation of l-methionine was accompanied by the formation of the transamination product 4-methylthio-2-oxobutyric acid. A branched-chain aminotransferase gene (YlBCA1) of Y. lipolytica was amplified, and the l-methionine-degrading activity and the aminotransferase activity were measured in a genetically modified strain and compared to those of the parental strain. Our work shows that l-methionine degradation via transamination is involved in formation of VSCs in Y. lipolytica. PMID:16085852

  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. 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.

  19. 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.

  20. Pressure-induced phase transitions in L-alanine, revisited.

    PubMed

    Tumanov, N A; Boldyreva, E V; Kolesov, B A; Kurnosov, A V; Quesada Cabrera, R

    2010-08-01

    The effect of pressure on L-alanine has been studied by X-ray powder diffraction (up to 12.3 GPa), single-crystal X-ray diffraction, Raman spectroscopy and optical microscopy (up to approximately 6 GPa). No structural phase transitions have been observed. At approximately 2 GPa the cell parameters a and b become accidentally equal to each other, but without a change in space-group symmetry. Neither of two transitions reported by others (to a tetragonal phase at approximately 2 GPa and to a monoclinic phase at approximately 9 GPa) was observed. The changes in cell parameters were continuous up to the highest measured pressures and the cells remained orthorhombic. Some important changes in the intermolecular interactions occur, which also manifest themselves in the Raman spectra. Two new orthorhombic phases could be crystallized from a MeOH/EtOH/H(2)O pressure-transmitting mixture in the pressure range 0.8-4.7 GPa, but only if the sample was kept at these pressures for at least 1-2 d. The new phases converted back to L-alanine on decompression. Judging from the Raman spectra and cell parameters, the new phases are most probably not L-alanine but its solvates.

  1. Life and cancer without telomerase: ALT and other strategies for making sure ends (don't) meet.

    PubMed

    Apte, Manasi S; Cooper, Julia Promisel

    2017-02-01

    While most cancer cells rely on telomerase expression/re-activation for linear chromosome maintenance and sustained proliferation, a significant population of cancers (10-15%) employs telomerase-independent strategies, collectively dubbed Alternative Lengthening of Telomeres (ALT). Most ALT cells relax the usual role of telomeres as inhibitors of local homologous recombination while maintaining the ability of telomeres to prohibit local non-homologous end joining reactions. Here we review current concepts surrounding how ALT telomeres achieve this new balance via alterations in chromatin landscape, DNA damage repair processes and handling of telomeric transcription. We also discuss telomerase independent end maintenance strategies utilized by other organisms, including fruitflies and yeasts, to draw parallels and contrasts and highlight additional modes, beyond ALT, that may be available to telomerase-minus cancers. We conclude by commenting on promises and challenges in the development of effective anti-ALT cancer therapies.

  2. Alanine metabolism in isolated human kidney tubules--Use of a mathematical model.

    PubMed

    Fouque, D; Dugelay, S; Martin, G; Combet, J; Baverel, G

    1996-02-15

    To gain insight into the fate of alanine nitrogen and carbon taken up by the human kidney under certain conditions, isolated human kidney cortex tubules were incubated in Krebs-Henseleit medium with L-alanine as substrate. The tubules metabolized alanine at high rates and in a dose-dependent manner. Most of the alanine nitrogen removed was recovered as ammonia and to a lesser extent as glutamate. Glucose, lactate and glutamate were also found to be significant products of alanine carbon metabolism. A simple mathematical model allowing one to calculate flux of alanine carbon through the various metabolic steps involved is proposed and applied to data obtained in experiments in which 5 mM [U-14C]-,[1-14C]-, [2-14C]- and [3-14C]alanine were used as substrates in parallel. About 40% of the alanine carbon removed was recovered as CO2 and oxidation of C1 of alanine accounted for most of the CO2 released from alanine. Calculations reveal that the ATP produced exceeded 3.2-fold the ATP consumed in relation to alanine metabolism. It is concluded that, in human kidney, alanine may serve as an energy supplier and as a precursor of glucose and ammonia.

  3. l-Alanine Auxotrophy of Lactobacillus johnsonii as Demonstrated by Physiological, Genomic, and Gene Complementation Approaches

    PubMed Central

    van der Kaaij, Hengameh; Desiere, Frank; Mollet, Beat; Germond, Jacques-Edouard

    2004-01-01

    Using a chemically defined medium without l-alanine, Lactobacillus johnsonii was demonstrated to be strictly auxotrophic for that amino acid. A comparative genetic analysis showed that all known genes involved in l-alanine biosynthesis are absent from the genome of L. johnsonii. This auxotrophy was complemented by heterologous expression of the Bacillus subtilis l-alanine dehydrogenase. PMID:15006820

  4. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

  5. Deciphering the role of aspartate and prephenate aminotransferase activities in plastid nitrogen metabolism.

    PubMed

    de la Torre, Fernando; El-Azaz, Jorge; Avila, 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.

  6. Characterization of the Aminotransferase ThdN from Thienodolin Biosynthesis in Streptomyces albogriseolus.

    PubMed

    Milbredt, Daniela; Patallo, Eugenio P; van Pée, Karl-Heinz

    2016-10-04

    In Streptomyces albogriseolus the indolethiophen alkaloid thienodolin is derived from tryptophan. The first step in thienodolin biosynthesis is the regioselective chlorination of tryptophan in the 6-position of the indole ring. The second step is catalyzed by the aminotransferase ThdN. ThdN shows sequence homology (up to 69 % similarity) with known pyridoxal 5'-phosphate-dependent aminotransferases of the aspartate aminotransferase family from Gram-positive bacteria. thdN was heterologously expressed in Pseudomonas fluorescens, and the enzyme was purified by nickel-affinity chromatography. ThdN is a homodimeric enzyme with a mass of 90 600 kDa and catalyzes the conversion of l-tryptophan and a number of chlorinated and brominated l-tryptophans. The lowest KM values were found for 6-bromo- and 6-chlorotryptophan (40 and 66 μm, respectively). For l-tryptophan it was 454 μm, which explains why thienodolin is the major product and dechlorothienodolin is only a minor component. The turnover number (kcat ) for 7-chlorotryptophan (128 min(-1) ) was higher than that for the natural substrate 6-chlorotryptophan (88 min(-1) ). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Inactivation of. gamma. -aminobutyric acid aminotransferase by (Z)-4-amino-2-fluorobut-2-enoic acid

    SciTech Connect

    Silverman, R.B.; George, C.

    1988-05-03

    (Z)-4-Amino-2-fluorobut-2-enoic acid (1) is shown to be a mechanism-based inactivator of pig brain ..gamma..-aminobutyric acid aminotransferase. Approximately 750 inactivator molecules are consumed prior to complete enzyme inactivation. Concurrent with enzyme inactivation is the release of 708 +/- 79 fluoride ions; transamination occurs 737 +/- 15 times per inactivation event. Inactivation of (/sup 3/H)pyridoxal 5'-phosphate ((/sup 3/H)PLP) reconstituted GABA aminotransferase by 1 followed by denaturation releases (/sup 3/H)PMP with no radioactivity remaining attached to the protein. A similar experiment carried out with 4-amino-5-fluoropent-2-enoic acid as the inactivator produces no (/sup 3/H)PMP; rather, another radioactive species is released. These results support an inactivation mechanism for 1 that involves normal catalytic isomerization followed by active site nucleophilic attack on the activated Michael acceptor. A general hypothesis for predicting the inactivation mechanism (Michael addition vs enamine addition) of GABA aminotransferase inactivators is proposed.

  8. The Alanine Racemase of Mycobacterium smegmatis Is Essential for Growth in the Absence of d-Alanine▿ †

    PubMed Central

    Milligan, Daniel L.; Tran, Sieu L.; Strych, Ulrich; Cook, Gregory M.; Krause, Kurt L.

    2007-01-01

    Alanine racemase, encoded by the gene alr, is an important enzyme in the synthesis of d-alanine for peptidoglycan biosynthesis. Strains of Mycobacterium smegmatis with a deletion mutation of the alr gene were found to require d-alanine for growth in both rich and minimal media. This indicates that alanine racemase is the only source of d-alanine for cell wall biosynthesis in M. smegmatis and confirms alanine racemase as a viable target gene for antimycobacterial drug development. PMID:17827284

  9. Isotopic effects in mechanistic studies of biotransformations of fluorine derivatives of L-alanine catalysed by L-alanine dehydrogenase.

    PubMed

    Szymańska-Majchrzak, Jolanta; Pałka, Katarzyna; Kańska, Marianna

    2017-05-01

    Synthesis of 3-fluoro-[2-(2)H]-L-alanine (3-F-[(2)H]-L-Ala) in reductive amination of 3-fluoropyruvic acid catalysed by L-alanine dehydrogenase (AlaDH) was described. Fluorine derivative was used to study oxidative deamination catalysed by AlaDH applied kinetic (for 3-F-L-Ala in H2O - KIE's on Vmax: 1.1; on Vmax/KM: 1.2; for 3-F-L-Ala in (2)H2O - on Vmax: 1.4; on Vmax/KM: 2.1) and solvent isotope effect methods (for 3-F-L-Ala - SIE's on Vmax: 1.0; on Vmax/KM: 0.87; for 3-F-[2-(2)H]-L-Ala - on Vmax: 1.4; on Vmax/KM: 1.5). Studies explain some details of reaction mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Biomaterial properties evaluation of poly(vinyl acetate- alt-maleic anhydride)/chitosan nanocapsules

    NASA Astrophysics Data System (ADS)

    Raţă, Delia Mihaela; Popa, Marcel; Chailan, Jean-François; Zamfir, Carmen Lăcrămioara; Peptu, Cătălina Anişoara

    2014-08-01

    Nanocapsules with diameter around 100 nm based on a natural polymer (chitosan) and a synthetic polymer poly(vinyl acetate- alt-maleic anhydride) [poly(MAVA)] by interfacial condensation method were prepared. The present study proposes a new type of biocompatible nanocapsules based on poly(vinyl acetate- alt-maleic anhydride-chitosan) (MCS) able to become a reliable support for inclusion and release of drugs. The spherical shape of the nanocapsules was evidenced by scanning electron microscopy. Nanocapsules presented a good Norfloxacin loading and release capacity. Haemocompatibility tests have demonstrated that the nanocapsules present a low toxicity and a good compatibility with sanguine medium. The biocompatibility properties of the nanocapsules after their intraperitoneal administration in rats were evidenced by histopathological examination of different organs (brain, liver, kidney, and lung). The results are encouraging and the nanocapsules can be used as controlled drug delivery systems.

  11. The larval specific lymphatic filarial ALT-2: induction of protection using protein or DNA vaccination.

    PubMed

    Ramachandran, Sabarinathan; Kumar, Mishra Pankaj; Rami, Reddy Maryada Venkata; Chinnaiah, Harinath Basker; Nutman, Thomas; Kaliraj, Perumal; McCarthy, James

    2004-01-01

    Genes from the infective stage of lymphatic filarial parasites expressed at the time of host invasion have been identified as potential vaccine candidates. By screening an L3 cDNA library with sera from uninfected longstanding residents of an area endemic for onchocerciasis, so-called "endemic normals" (EN), we have cloned and characterized one such gene termed the abundant larval transcript two (ALT-2). The stage specificity of ALT-2 gene transcription and protein synthesis was confirmed by PCR using genespecific primers, and by western blot analysis of protein extracts from various stages of the parasite life cycle using specific antisera. Significant differences in antibody response to the recombinant ALT-2 were observed in endemic populations with differing clinical manifestations of lymphatic filariasis with an antibody response present in sera from 18 of 25 (72%) EN subjects compared to 9 of 25 (36%) with subclinical microfilaracmia (MF) and 14 of 25 (52%) of those with chronic lymphatic obstruction (CP) (P=0.01 for comparison of EN to CP or to MF). This differential responsiveness suggests that the protective immunity postulated to account for their uninfected status might be associated with a response to this protein. When the utility of ALT-2 as a vaccine candidate was tested in a murine model using either recombinant protein or a DNA vaccine construct, statistically significant protection was observed when compared to a control filarial gene product expressed across all stages of the parasite lifecycle (SXP-1; P=0.02 for protein and P=0.01 for the DNA vaccine) or compared to adjuvant alone. This level of protection indicates that this vaccine is a promising candidate for further development.

  12. Telomeric overhang length determines structural dynamics and accessibility to telomerase and ALT associated proteins

    PubMed Central

    Hwang, Helen; Kreig, Alex; Calvert, Jacob; Lormand, Justin; Kwon, Yongho; Daley, James M.; Sung, Patrick; Opresko, Patricia L.; Myong, Sua

    2014-01-01

    The G-rich single stranded DNA at the 3′ end of human telomeres can self-fold into G-quaduplex (GQ). However, telomere lengthening by telomerase or the recombination-based alternative lengthening of telomere (ALT) mechanism requires protein loading on the overhang. Using single molecule fluorescence spectroscopy we discovered that lengthening the telomeric overhang also increased the rate of dynamic exchanges between structural conformations. Overhangs with five to seven TTAGGG repeats, compared to four repeats, showed much greater dynamics and accessibility to telomerase binding and activity, and loading of the ALT-associated proteins RAD51, WRN and BLM. Although the eight repeats are highly dynamic, they can fold into two GQs, which limited protein accessibility. In contrast, the telomere-specific protein, POT1 is unique in that it binds independently of repeat number. Our results suggest that the telomeric overhang length and dynamics may contribute to the regulation of telomere extension via telomerase action and the ALT mechanism. PMID:24836024

  13. Alternative Liquid Fuels Simulation Model (AltSim) v. 2.0

    SciTech Connect

    Baker, Arnold; Thomas, Drennan; Williams, Ryan

    2010-02-24

    The Alternative Liquid Fuels Simulation Model (AltSim) is a high-level dynamic simulation model which calculates and compares the production and end use costs, energy balances, and greenhouse gas emissions for several alternative liquid transportation fuels. These fuels include: corn ethanol, cellulosic ethanol from various feedstocks, biodiesel, and diesels derived from natural gas (gas to liquid, or GTL), coal (coal to liquid, or CTL), and coal with biomass (CBTL). AltSim allows for comprehensive sensitivity analyses on capital costs, operation and maintenance costs, renewable and fossil fuel feedstock costs, feedstock conversion efficiency, financial assumptions, tax credits, CO2 taxes, and plant capacity factor. AltSim also includes policy tools to allow for consideration of greenhouse gas offset policies, production tax credits, and land use requirements. The main goal is to allow interested stakeholders to understand the complicated economic and environmental tradeoffs associated with the various options. The software is designed to address policy questions related to the economic competitiveness of technologies under different economic and technical assumptions. This model will be used to inform policy makers and staff about the economic and environmental tradeoffs associated with various fuel alternatives.

  14. Development of PCR-based codominant markers flanking the Alt3 gene in rye.

    PubMed

    Miftahudin; Scoles, G J; Gustafson, J P

    2004-04-01

    Aluminum (Al) toxicity is considered to be a major problem for crop growth and production on acid soils. The ability of crops to overcome Al toxicity varies among crop species and cultivars. Rye (Secale cereale L.) is the most Al-tolerant species among the Triticeae. Our previous study showed that Al tolerance in a rye F6 recombinant inbred line (RIL) population was controlled by a single gene designated as the aluminum tolerance (Alt3) gene on chromosome 4RL. Based on the DNA sequence of a rice (Oryza sativa L.) BAC clone suspected to be syntenic to the Alt3 gene region, we developed two PCR-based codominant markers flanking the gene. These two markers, a sequence-tagged site (STS) marker and a cleaved amplified polymorphic sequence (CAPS) marker, each flanked the Alt3 gene at an approximate distance of 0.4 cM and can be used to facilitate high-resolution mapping of the gene. The markers might also be used for marker-assisted selection in rye or wheat (Triticum aestivum L.) breeding programs to obtain Al-tolerant lines and (or) cultivars.

  15. Twist-3 fragmentation effects for ALT in light hadron production from proton-proton collisions

    DOE PAGES

    Koike, Y.; Pitonyak, D.; Takagi, Y.; ...

    2015-11-11

    Here, we compute the contribution from the twist-3 fragmentation function for light hadron production in collisions between transversely and longitudinally polarized protons, i.e., View the MathML sourcep↑p→→hX, which can cause a double-spin asymmetry (DSA) ALT. This is a naïve T-even twist-3 observable that we analyze in collinear factorization using both Feynman gauge and lightcone gauge as well as give a general proof of color gauge invariance. So far only twist-3 effects in the transversely polarized proton have been studied for ALT in p↑p→→hX. However, there are indications that the naïve T-odd transverse single-spin asymmetry (SSA) AN in p↑p→hX is dominatedmore » not by such distribution effects but rather by a fragmentation mechanism. Therefore, one may expect similarly that the fragmentation contribution is important for ALT. As a result, given possible plans at RHIC to measure this observable, it is timely to provide a calculation of this term.« less

  16. The Alt-Az Initiative for Lightweight Research Telescopes: Scientific Research Programs and Engineering Developments

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.

    2009-05-01

    The Alt-Az Initiative is a catalyst for the development of low cost, lightweight, modest aperture (2 meters and less) alt-az research telescopes. Such telescopes, especially when automated and networked, can be cost-effective tools for dedicated research programs including low and high resolution fiber fed spectroscopy as well as optical, near infrared, and high speed photometry. To date, six two-day workshops and two full conferences have been held. Nearly a dozen technical initiatives have been completed or are underway. These include optical designs, lightweight mirrors, active primary mirror controls, and direct drive motors and controllers. One low cost, lightweight, technical demonstration telescope w