Molecular and Thermodynamic Mechanisms of the Chloride-dependent Human Angiotensin-I-converting Enzyme (ACE)*

PubMed Central

Yates, Christopher J.; Masuyer, Geoffrey; Schwager, Sylva L. U.; Akif, Mohd; Sturrock, Edward D.; Acharya, K. Ravi

2014-01-01

Somatic angiotensin-converting enzyme (sACE), a key regulator of blood pressure and electrolyte fluid homeostasis, cleaves the vasoactive angiotensin-I, bradykinin, and a number of other physiologically relevant peptides. sACE consists of two homologous and catalytically active N- and C-domains, which display marked differences in substrate specificities and chloride activation. A series of single substitution mutants were generated and evaluated under varying chloride concentrations using isothermal titration calorimetry. The x-ray crystal structures of the mutants provided details on the chloride-dependent interactions with ACE. Chloride binding in the chloride 1 pocket of C-domain ACE was found to affect positioning of residues from the active site. Analysis of the chloride 2 pocket R522Q and R522K mutations revealed the key interactions with the catalytic site that are stabilized via chloride coordination of Arg522. Substrate interactions in the S2 subsite were shown to affect chloride affinity in the chloride 2 pocket. The Glu403-Lys118 salt bridge in C-domain ACE was shown to stabilize the hinge-bending region and reduce chloride affinity by constraining the chloride 2 pocket. This work demonstrated that substrate composition to the C-terminal side of the scissile bond as well as interactions of larger substrates in the S2 subsite moderate chloride affinity in the chloride 2 pocket of the ACE C-domain, providing a rationale for the substrate-selective nature of chloride dependence in ACE and how this varies between the N- and C-domains. PMID:24297181

Analysis and Evaluation of the Inhibitory Mechanism of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Derived from Casein Hydrolysate.

PubMed

Tu, Maolin; Liu, Hanxiong; Zhang, Ruyi; Chen, Hui; Mao, Fengjiao; Cheng, Shuzhen; Lu, Weihong; Du, Ming

2018-04-25

Casein hydrolysates exert various biological activities, and the responsible functional peptides are being identified from them continuously. In this study, the tryptic casein hydrolysate was fractionated by an ultrafiltration membrane (3 kDa), and the peptides were identified by capillary electrophoresis-quadrupole-time-of-flight-tandem mass spectrometry. Meanwhile, in silico methods were used to analyze the toxicity, solubility, stability, and affinity between the peptides and angiotensin-I-converting enzyme (ACE). Finally, a new angiotensin-I-converting enzyme inhibitory (ACEI) peptide, EKVNELSK, derived from α s1 -casein (fragment 35-42) was screened. The half maximal inhibitory concentration value of the peptide is 5.998 mM, which was determined by a high-performance liquid chromatography method. The Lineweaver-Burk plot indicated that this peptide is a mixed-type inhibitor against ACE. Moreover, Discovery Studio 2017 R2 software was adopted to perform molecular docking to propose the potential mechanisms underlying the ACEI activity of the peptide. These results indicated that EKVNELSK is a new ACEI peptide identified from casein hydrolysate.

Glutamic acid is an active site residue of angiotensin I-converting enzyme. Use of the Lossen rearrangement for identification of dicarboxylic acid residues.

PubMed

Harris, R B; Wilson, I B

1983-01-25

A set of chemical reactions was used to show that one glutamic acid residue at the active site of bovine lung angiotensin I-converting enzyme is esterified with the alkylating agent p-[N,N-bis(chloroethyl)amino] phenylbutyryl-L-Pro (chlorambucyl-L-Pro), an affinity label for this enzyme (Harris, R. B., and Wilson, I. B. (1982) J. Biol. Chem. 257, 811-815). The same procedure was used to confirm that a glutamic acid residue of carboxypeptidase A alpha is esterified by reaction with bromoacetyl-N-methyl-L-phenylalanine (Haas, G. M., and Neurath, H. (1971) Biochemistry 10, 3535-3546). In the procedure described in this paper, the esterified residue at the active site is converted to the hydroxamic acid by reaction with hydroxylamine and the hydroxamic acid is subject to the Lossen rearrangement. If a glutamic acid residue was esterified, 1 eq of 2,4-diaminobutyric acid will be formed. Aspartyl esters will give 2,3-diaminopropionic acid. The diamino acids can be quantitatively measured using the short column of an amino acid analyzer if the amount of lysine and histidine is largely decreased by modification with suitable side chain protecting groups. With carboxypeptidase A, the reactions were done on the whole undigested enzyme. With the converting enzyme, we first cleaved the esterified enzyme with cyanogen bromide. Twenty-nine cleavage peptides were separated on high performance liquid chromatography and one of these contained all of the bound radioactive inhibitor. This active site peptide was then subjected to the derivatization and Lossen procedures, and 1 eq of 2,4-diaminobutyric acid was obtained.

Assay for Angiotensin-Converting Enzyme.

ERIC Educational Resources Information Center

Russo, Salvatore F.

1983-01-01

Describes a three-hour experiment designed to introduce students to chemistry of the angiotensis-converting enzyme, illustrate design of a quenched fluorescence substrate, and examine considerations necessary in designing a clinical assay. Includes background information on the biochemistry of hypertension, reagents/materials needed, procedures…

Purification and characterization of angiotensin I converting enzyme inhibition peptides from sandworm Sipunculus nudus

NASA Astrophysics Data System (ADS)

Sun, Xueping; Wang, Man; Liu, Buming; Sun, Zhenliang

2017-10-01

Three angiotensin I converting enzyme (ACE) inhibition peptides were isolated from sandworm Sipunculus nudus protein hydrolysate prepared using protamex. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography (RP-HPLC), were used to isolate the ACE inhibition peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp-Glu-Phe. The IC50 values of the purified peptides for ACE inhibition activity were 34.72 μmol L-1, 20.55 μmol L-1 and 22.77 μmol L-1, respectively. These results suggested that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources.

A virtual screening method for inhibitory peptides of Angiotensin I-converting enzyme.

PubMed

Wu, Hongxi; Liu, Yalan; Guo, Mingrong; Xie, Jingli; Jiang, XiaMin

2014-09-01

Natural small peptides from foods have been proven to be efficient inhibitors of Angiotensin I-converting enzyme (ACE) for the regulation of blood pressure. The traditional ACE inhibitory peptides screening method is both time consuming and money costing, to the contrary, virtual screening method by computation can break these limitations. We establish a virtual screening method to obtain ACE inhibitory peptides with the help of Libdock module of Discovery Studio 3.5 software. A significant relationship between Libdock score and experimental IC(50) was found, Libdock score = 10.063 log(1/IC(50)) + 68.08 (R(2) = 0.62). The credibility of the relationship was confirmed by testing the coincidence of the estimated log(1/IC(50)) and measured log(1/IC(50)) (IC(50) is 50% inhibitory concentration toward ACE, in μmol/L) of 5 synthetic ACE inhibitory peptides, which was virtual hydrolyzed and screened from a kind of seafood, Phascolosoma esculenta. Accordingly, Libdock method is a valid IC(50) estimation tool and virtual screening method for small ACE inhibitory peptides. © 2014 Institute of Food Technologists®

21 CFR 862.1090 - Angiotensin converting enzyme (A.C.E.) test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Angiotensin converting enzyme (A.C.E.) test system... Test Systems § 862.1090 Angiotensin converting enzyme (A.C.E.) test system. (a) Identification. An angiotensin converting enzyme (A.C.E.) test system is a device intended to measure the activity of angiotensin...

Localization and characterization of angiotensin II receptor binding and angiotensin converting enzyme in the human medulla oblongata.

PubMed

Allen, A M; Chai, S Y; Clevers, J; McKinley, M J; Paxinos, G; Mendelsohn, F A

1988-03-08

Angiotensin II receptor and angiotensin converting enzyme distributions in the human medulla oblongata were localised by quantitative in vitro autoradiography. Angiotensin II receptors were labelled with the antagonist analogue 125I-[Sar1, Ile8] AII while angiotensin converting enzyme was labelled with 125I-351A, a derivative of the specific converting enzyme inhibitor, lisinopril. Angiotensin II receptor binding and angiotensin converting enzyme are present in high concentrations in the nucleus of the solitary tract, the dorsal motor nucleus of vagus, the rostral and caudal ventrolateral reticular nucleus, and in a band connecting the dorsal and ventral regions. In the rostral and caudal ventrolateral reticular nucleus, angiotensin II receptors are distributed in a punctate pattern that registers with neuronal cell bodies. The distribution and density of these cell bodies closely resemble those of catecholamine-containing neurones mapped by others. In view of the known interactions of angiotensin II with both central and peripheral catecholamine-containing neurons of laboratory animals, the current anatomical findings suggest similar interactions between these neuroactive compounds in the human central nervous system. The presence of angiotensin II receptors and angiotensin converting enzyme in the nucleus of the solitary tract, dorsal motor nucleus of vagus, and rostral and caudal ventrolateral reticular nucleus demonstrates sites for central angiotensin II to exert its known actions on vasopressin release and autonomic functions including blood pressure control. These data also suggest a possible interaction between angiotensin II and central catecholeminergic systems.

Inhibition of angiotensin I converting enzyme by subtilisin NAT (nattokinase) in natto, a Japanese traditional fermented food.

PubMed

Murakami, Keiko; Yamanaka, Naoki; Ohnishi, Katsunori; Fukayama, Minoru; Yoshino, Masataka

2012-06-01

Angiotensin I converting enzyme (ACE) was inhibited by the culture medium of Bacillus subtilis subsp. natto, which ferments boiled soy beans to natto, a Japanese traditional food. Subtilisin NAT (nattokinase) produced by B. subtilis also inhibited ACE, and the inhibition was markedly stimulated by heat treatment of subtilisin at 120 °C for 15 min. Inhibition of ACE by subtilisin was of a mixed type: the decrease in V(max) and the increase in K(m) value. SDS-polyacrylamide gel electrophoresis showed that heat treatment of subtilisin caused inactivation with fragmentation of the enzyme protein into small peptides. The inhibitory action of subtilisin was not due to an enzymatic action of protease, but may be ascribed to the potent ACE-inhibitory peptides such as LY and FY, amino acid sequences in subtilisin. HPLC-MS analysis of heat-inactivated subtilisin confirmed that LY and FY were liberated by fragmentation of the enzyme. Inhibition of ACE by subtilisin and its degradation peptides such as LY and FY may participate in the suppression of blood pressure by ingestion of natto.

Human gut endogenous proteins as a potential source of angiotensin-I-converting enzyme (ACE-I)-, renin inhibitory and antioxidant peptides.

PubMed

Dave, Lakshmi A; Hayes, Maria; Montoya, Carlos A; Rutherfurd, Shane M; Moughan, Paul J

2016-02-01

It is well known that endogenous bioactive proteins and peptides play a substantial role in the body's first line of immunological defence, immune-regulation and normal body functioning. Further, the peptides derived from the luminal digestion of proteins are also important for body function. For example, within the peptide database BIOPEP (http://www.uwm.edu.pl/biochemia/index.php/en/biopep) 12 endogenous antimicrobial and 64 angiotensin-I-converting enzyme (ACE-I) inhibitory peptides derived from human milk and plasma proteins are listed. The antimicrobial peptide database (http://aps.unmc.edu/AP/main.php) lists over 111 human host-defence peptides. Several endogenous proteins are secreted in the gut and are subject to the same gastrointestinal digestion processes as food proteins derived from the diet. The human gut endogenous proteins (GEP) include mucins, serum albumin, digestive enzymes, hormones, and proteins from sloughed off epithelial cells and gut microbiota, and numerous other secreted proteins. To date, much work has been carried out regarding the health altering effects of food-derived bioactive peptides but little attention has been paid to the possibility that GEP may also be a source of bioactive peptides. In this review, we discuss the potential of GEP to constitute a gut cryptome from which bioactive peptides such as ACE-I inhibitory, renin inhibitory and antioxidant peptides may be derived. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular recognition and regulation of human angiotensin-I converting enzyme (ACE) activity by natural inhibitory peptides

PubMed Central

Masuyer, Geoffrey; Schwager, Sylva L. U.; Sturrock, Edward D.; Isaac, R. Elwyn; Acharya, K. Ravi

2012-01-01

Angiotensin-I converting enzyme (ACE), a two-domain dipeptidylcarboxypeptidase, is a key regulator of blood pressure as a result of its critical role in the renin-angiotensin-aldosterone and kallikrein-kinin systems. Hence it is an important drug target in the treatment of cardiovascular diseases. ACE is primarily known for its ability to cleave angiotensin I (Ang I) to the vasoactive octapeptide angiotensin II (Ang II), but is also able to cleave a number of other substrates including the vasodilator bradykinin and N-acetyl-Ser-Asp-Lys-Pro (Ac-SDKP), a physiological modulator of hematopoiesis. For the first time we provide a detailed biochemical and structural basis for the domain selectivity of the natural peptide inhibitors of ACE, bradykinin potentiating peptide b and Ang II. Moreover, Ang II showed selective competitive inhibition of the carboxy-terminal domain of human somatic ACE providing evidence for a regulatory role in the human renin-angiotensin system (RAS). PMID:23056909

Angiotensin-converting enzyme 2 ectodomain shedding cleavage-site identification: determinants and constraints.

PubMed

Lai, Zon W; Hanchapola, Iresha; Steer, David L; Smith, A Ian

2011-06-14

ADAM17, also known as tumor necrosis factor α-converting enzyme, is involved in the ectodomain shedding of many integral membrane proteins. We have previously reported that ADAM17 is able to mediate the cleavage secretion of the ectodomain of human angiotensin-converting enzyme 2 (ACE2), a functional receptor for the severe acute respiratory syndrome coronavirus. In this study, we demonstrate that purified recombinant human ADAM17 is able to cleave a 20-amino acid peptide mimetic corresponding to the extracellular juxtamembrane region of human ACE2 between Arg(708) and Ser(709). A series of peptide analogues were also synthesized, showing that glutamate subtitution at Arg(708) and/or Arg(710) attenuated the cleavage process, while alanine substitution at Arg(708) and/or Ser(709) did not inhibit peptide cleavage by recombinant ADAM17. Analysis of CD spectra showed a minimal difference in the secondary structure of the peptide analogues in the buffer system used for the ADAM17 cleavage assay. The observation of the shedding profiles of ACE2 mutants expressing CHO-K1 and CHO-P cells indicates that the Arg(708) → Glu(708) mutation and the Arg(708)Arg(710) → Glu(708)Glu(710) double mutation produced increases in the amount of ACE2 shed when stimulated by phorbol ester PMA. In summary, we have demonstrated that ADAM17 is able to cleave ACE2 peptide sequence analogues between Arg(708) and Ser(709). These findings also indicate that Arg(708) and Arg(710) play a role in site recognition in the regulation of ACE2 ectodomain shedding mediated by ADAM17.

Novel angiotensin I-converting enzyme inhibitory peptides isolated from Alcalase hydrolysate of mung bean protein.

PubMed

Li, Guan-Hong; Wan, Ju-Zhen; Le, Guo-Wei; Shi, Yong-Hui

2006-08-01

Mung bean protein isolates were hydrolyzed for 2 h by Alcalase. The generated hydrolysate showed angiotensin I-converting enzyme (ACE) inhibitory activity with the IC(50) value of 0.64 mg protein/ml. Three kinds of novel ACE inhibitory peptides were isolated from the hydrolysate by Sephadex G-15 and reverse-phase high performance liquid chromatography (RP-HPLC). These peptides were identified by amino acid composition analysis and matrix assisted-laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF MS/MS), as Lys-Asp-Tyr-Arg-Leu, Val-Thr-Pro-Ala-Leu-Arg and Lys-Leu-Pro-Ala-Gly-Thr-Leu-Phe with the IC(50) values of 26.5 microM, 82.4 microM and 13.4 microM, respectively. Copyright (c) 2006 European Peptide Society and John Wiley & Sons, Ltd.

Screening the Brazilian flora for antihypertensive plant species for in vitro angiotensin-I-converting enzyme inhibiting activity.

PubMed

Castro Braga, F; Wagner, H; Lombardi, J A; de Oliveira, A B

2000-06-01

The evaluation of several antihypertensive activity of Brazilian plant species was performed using in vitro inhibition of the angiotensin I-converting enzyme (ACE). Nineteen species belonging to 13 families were investigated. Plants were selected based on their use as diuretics and on a chemosystematic consideration. Extracts of the following species presented the highest ACE inhibition rate, at concentrations of 0.33 mg/ml: Ouratea semiserrata (Mart. & Nees) Engl. stems (68%), Cuphea cartagenesis (Jacq.) Macbride leaves (50%) and Mansoa hirsuta DC. leaves (54%). Some hypotheses about the nature of the compounds that may be responsible for the activity of these species are discussed in the paper.

Angiotensin-converting enzyme genetic polymorphism: its impact on cardiac remodeling

PubMed Central

de Albuquerque, Felipe Neves; Brandão, Andréa Araujo; da Silva, Dayse Aparecida; Mourilhe-Rocha, Ricardo; Duque, Gustavo Salgado; Gondar, Alyne Freitas Pereira; Neves, Luiza Maceira de Almeida; Bittencourt, Marcelo Imbroinise; Pozzan, Roberto; de Albuquerque, Denilson Campos

2014-01-01

Background The role of angiotensin-converting enzyme genetic polymorphisms as a predictor of echocardiographic outcomes on heart failure is yet to be established. The local profile should be identified so that the impact of those genotypes on the Brazilian population could be identified. This is the first study on exclusively non-ischemic heart failure over a follow-up longer than 5 years. Objective To determine the distribution of angiotensin-converting enzyme genetic polymorphism variants and their relation with echocardiographic outcome of patients with non-ischemic heart failure. Methods Secondary analysis of the medical records of 111 patients and identification of the angiotensin-converting enzyme genetic polymorphism variants, classified as DD (Deletion/Deletion), DI (Deletion/Insertion) or II (Insertion/Insertion). Results The cohort means were as follows: follow-up, 64.9 months; age, 59.5 years; male sex, 60.4%; white skin color, 51.4%; use of beta-blockers, 98.2%; and use of angiotensin-converting-enzyme inhibitors or angiotensin receptor blocker, 89.2%. The angiotensin-converting enzyme genetic polymorphism distribution was as follows: DD, 51.4%; DI, 44.1%; and II, 4.5%. No difference regarding the clinical characteristics or treatment was observed between the groups. The final left ventricular systolic diameter was the only isolated echocardiographic variable that significantly differed between the angiotensin-converting enzyme genetic polymorphisms: 59.2 ± 1.8 for DD versus 52.3 ± 1.9 for DI versus 59.2 ± 5.2 for II (p = 0.029). Considering the evolutionary behavior, all echocardiographic variables (difference between the left ventricular ejection fraction at the last and first consultation; difference between the left ventricular systolic diameter at the last and first consultation; and difference between the left ventricular diastolic diameter at the last and first consultation) differed between the genotypes (p = 0.024; p = 0.002; and p = 0

Angiotensin-converting enzyme genetic polymorphism: its impact on cardiac remodeling.

PubMed

Albuquerque, Felipe Neves de; Brandão, Andréa Araujo; Silva, Dayse Aparecida da; Mourilhe-Rocha, Ricardo; Duque, Gustavo Salgado; Gondar, Alyne Freitas Pereira; Neves, Luiza Maceira de Almeida; Bittencourt, Marcelo Imbroinise; Pozzan, Roberto; Albuquerque, Denilson Campos de

2014-01-01

The role of angiotensin-converting enzyme genetic polymorphisms as a predictor of echocardiographic outcomes on heart failure is yet to be established. The local profile should be identified so that the impact of those genotypes on the Brazilian population could be identified. This is the first study on exclusively non-ischemic heart failure over a follow-up longer than 5 years. To determine the distribution of angiotensin-converting enzyme genetic polymorphism variants and their relation with echocardiographic outcome of patients with non-ischemic heart failure. Secondary analysis of the medical records of 111 patients and identification of the angiotensin-converting enzyme genetic polymorphism variants, classified as DD (Deletion/Deletion), DI (Deletion/Insertion) or II (Insertion/Insertion). The cohort means were as follows: follow-up, 64.9 months; age, 59.5 years; male sex, 60.4%; white skin color, 51.4%; use of beta-blockers, 98.2%; and use of angiotensin-converting-enzyme inhibitors or angiotensin receptor blocker, 89.2%. The angiotensin-converting enzyme genetic polymorphism distribution was as follows: DD, 51.4%; DI, 44.1%; and II, 4.5%. No difference regarding the clinical characteristics or treatment was observed between the groups. The final left ventricular systolic diameter was the only isolated echocardiographic variable that significantly differed between the angiotensin-converting enzyme genetic polymorphisms: 59.2 ± 1.8 for DD versus 52.3 ± 1.9 for DI versus 59.2 ± 5.2 for II (p = 0.029). Considering the evolutionary behavior, all echocardiographic variables (difference between the left ventricular ejection fraction at the last and first consultation; difference between the left ventricular systolic diameter at the last and first consultation; and difference between the left ventricular diastolic diameter at the last and first consultation) differed between the genotypes (p = 0.024; p = 0.002; and p = 0.021, respectively). The distribution of

Purification of angiotensin I-converting enzyme (ACE) inhibitory peptides from casein hydrolysate by IMAC-Ni2.

PubMed

Wu, Shanguang; Feng, Xuezhen; Lu, Yuan; Lu, Yuting; Liu, Saisai; Tian, Yuhong

2017-10-01

Casein proteins were hydrolyzed by papain to identify inhibitory peptides of angiotensin I-converting enzyme (ACE). The hydrolysate was fractionized by immobilized metal affinity chromatography (IMAC-Ni 2+ ). The fraction with high ACE inhibitory activity was enriched and further chromatographed on a reverse-phase column to yield four fractions. Among the fractions, the L4 fraction exhibited the highest ACE inhibitory activity and was identified by sequence analysis as Trp-Tyr-Leu-His-Tyr-Ala (WYLHYA), with IC 50 value of 16.22 ± 0.83 µM in vitro. This peptide was expected to be applied as an ingredient for preventing hypertension and IMAC-Ni 2+ may provide a simple method for purification of ACE inhibitory peptides.

Angiotensin I-Converting Enzyme Inhibitor Activity on Egg Albumen Fermentation

PubMed Central

Nahariah, N.; Legowo, A. M.; Abustam, E.; Hintono, A.

2015-01-01

Lactobacillus plantarum is used for fermentation of fish products, meat and milk. However, the utilization of these bacteria in egg processing has not been done. This study was designed to evaluate the potential of fermented egg albumen as a functional food that is rich in angiotensin I-converting enzyme inhibitors activity (ACE-inhibitor activity) and is antihypertensive. A completely randomized design was used in this study with six durations of fermentation (6, 12, 18, 24, 30, and 36 h) as treatments. Six hundred eggs obtained from the same chicken farm were used in the experiment as sources of egg albumen. Bacteria L. plantarum FNCC 0027 used in the fermentation was isolated from cow’s milk. The parameters measured were the total bacteria, dissolved protein, pH, total acid and the activity of ACE-inhibitors. The results showed that there were significant effects of fermentation time on the parameters tested. Total bacteria increased significantly during fermentation for 6, 12, 18, and 24 h and then decreased with the increasing time of fermentation to 30 and 36 h. Soluble protein increased significantly during fermentation to 18 h and then subsequently decreased during of fermentation to 24, 30, and 36 h. The pH value decreased markedly during fermentation. The activities of ACE-inhibitor in fermented egg albumen increased during fermentation to 18 h and then decreased with the increasing of the duration of fermentation to 24, 30, and 36 h. The egg albumen which was fermented for 18 h resulted in a functional food that was rich in ACE-inhibitor activity. PMID:25715689

In vitro angiotensin I converting enzyme inhibition by a peptide isolated from Chiropsalmus quadrigatus Haeckel (box jellyfish) venom hydrolysate.

PubMed

So, Pamela Berilyn T; Rubio, Peter; Lirio, Stephen; Macabeo, Allan Patrick; Huang, Hsi-Ya; Corpuz, Mary Jho-Anne T; Villaflores, Oliver B

2016-09-01

The anti-angiotensin I converting enzyme activity of box jellyfish, Chiropsalmus quadrigatus Haeckel venom hydrolysate was studied. The venom extract was obtained by centrifugation and ultrasonication. Protein concentration of 12.99 μg/mL was determined using Bradford assay. The pepsin and papain hydrolysate was tested for its toxicity by Limit test following the OECD Guideline 425 using 5 female Sprague-Dawley rats. Results showed that the hydrolysate is nontoxic with an LD50 above 2000 mg/kg. In vitro angiotensin I converting enzyme (ACE) inhibitory activity was determined using ACE kit-WST. Isolation of ACE inhibitory peptides using column chromatography with SP-Sephadex G-25 yielded 8 pooled fractions with fraction 3 (86.5%) exhibiting the highest activity. This was followed by reverse phase - high performance liquid chromatography (RP-HPLC) with an octadecyl silica column (Inertsil ODS-3) using methanol:water 15:85 at a flow rate of 1.0 mL/min. Among the 13 fractions separated with the RP-HPLC, fraction 3.5 exhibited the highest ACE inhibitory activity (84.1%). The peptide sequence ACPGPNPGRP (IC50 2.03 μM) from fraction 3.5 was identified using Matrix-assisted laser desorption/ionization with time-of-flight tandem mass spectroscopy analysis (MALDI-TOF/MS). Copyright © 2016 Elsevier Ltd. All rights reserved.

ANGIOTENSIN CONVERTING ENZYME INHIBITION AND NOVEL CARDIOVASCULAR RISK BIOMARKERS

PubMed Central

Cesari, Matteo; Kritchevsky, Stephen B.; Atkinson, Hal H.; Penninx, Brenda W.; Di Bari, Mauro; Tracy, Russell P.; Pahor, Marco

2015-01-01

Background Beneficial effects of angiotensin converting enzyme (ACE) inhibitors seem to be mediated by mechanisms that are partly independent of blood pressure lowering. The present study evaluates effects of an ACE-inhibitor (i.e. fosinopril) intervention on novel cardiovascular risk factors. Methods Data are from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN), a double-blind, crossover, randomized, placebo-controlled trial enrolling subjects aged ≥55 years and older with high cardiovascular disease risk profile. Biomarkers of hemostasis (i.e. plasminogen activator inhibitor-1 [PAI-1], D-dimer), inflammation (i.e. C-reactive protein [CRP], interleukin-6 [IL-6]), and endothelial function (i.e. endothelin-1, vascular cell adhesion molecule-1 [VCAM-1]) were measured at the baseline, at the mid-term, and at end of follow-up (after one year) clinic visits. Paired t-test analyses (after Sidak’s adjustment, p value<0.009) were performed to compare biomarkers modifications after fosinopril/placebo interventions. Results Mean age of the sample (n=290, women 43.4%) was 66.0 years old. No significant differences were reported for CRP, IL-6, PAI-1, VCAM-1, and endothelin-1 levels in the comparisons between fosinopril and placebo interventions. D-Dimer was the only biomarker showing a significant difference between fosinopril intervention (median 0.32 [interquartile range, IQR 0.22–0.52] µg/mL) and placebo (median 0.29 [IQR 0.20–0.47] µg/mL, p=0.007) when analyses were restricted to participants with higher compliance to treatment and receiving the maximum ACE-inhibitor dosage. Conclusions ACE-inhibition does not significantly modify major biomarkers of inflammation, hemostasis, and endothelial function. Further studies should confirm the possible effect of ACE-inhibitors on the fibrinolysis pathway. PMID:19185642

Identification of interleukin-8 converting enzyme as cathepsin L.

PubMed

Ohashi, Kensaku; Naruto, Masanobu; Nakaki, Toshio; Sano, Emiko

2003-06-26

IL-8 is produced by various cells, and the NH(2)-terminal amino acid sequence of IL-8 displays heterogeneity among cell types. The mature form of IL-8 has 72 amino acids (72IL-8), while a precursor form (77IL-8) of IL-8 has five additional amino acids to the 72IL-8 NH(2)-terminal. However, it has been unclear how IL-8 is processed to yield the mature form. In this study, converting enzyme was purified as a single 31-kDa band on silver-stained polyacrylamide gel from 160 l of cultured fibroblast supernatant by sequential chromatography. NH(2)-terminal amino acid sequence analysis revealed a sequence, EAPRSVDWRE, which was identified as a partial sequence of cathepsin L. Polyclonal antibodies raised against cathepsin L recognized the purified converting enzyme on Western blot. Moreover, human hepatic cathepsin L cleaved 77IL-8 between Arg(5) and Ser(6), which is the same cleavage site as the putative converting enzyme, resulting in 72IL-8 formation. These data indicate that the converting enzyme of the partially purified fraction of the human fibroblast culture supernatant was cathepsin L. Furthermore, 72IL-8 was sevenfold more potent than 77IL-8 in a neutrophil chemotaxis assay. These results show that cathepsin L is secreted from human fibroblasts in response to external stimuli and plays an important role in IL-8 processing in inflammatory sites.

Angiotensin-converting enzyme 2 activation improves endothelial function.

PubMed

Fraga-Silva, Rodrigo A; Costa-Fraga, Fabiana P; Murça, Tatiane M; Moraes, Patrícia L; Martins Lima, Augusto; Lautner, Roberto Q; Castro, Carlos H; Soares, Célia Maria A; Borges, Clayton L; Nadu, Ana Paula; Oliveira, Marilene L; Shenoy, Vinayak; Katovich, Michael J; Santos, Robson A S; Raizada, Mohan K; Ferreira, Anderson J

2013-06-01

Diminished release and function of endothelium-derived nitric oxide coupled with increases in reactive oxygen species production is critical in endothelial dysfunction. Recent evidences have shown that activation of the protective axis of the renin-angiotensin system composed by angiotensin-converting enzyme 2, angiotensin-(1-7), and Mas receptor promotes many beneficial vascular effects. This has led us to postulate that activation of intrinsic angiotensin-converting enzyme 2 would improve endothelial function by decreasing the reactive oxygen species production. In the present study, we tested 1-[[2-(dimetilamino)etil]amino]-4-(hidroximetil)-7-[[(4-metilfenil)sulfonil]oxi]-9H-xantona-9 (XNT), a small molecule angiotensin-converting enzyme 2 activator, on endothelial function to validate this hypothesis. In vivo treatment with XNT (1 mg/kg per day for 4 weeks) improved the endothelial function of spontaneously hypertensive rats and of streptozotocin-induced diabetic rats when evaluated through the vasorelaxant responses to acetylcholine/sodium nitroprusside. Acute in vitro incubation with XNT caused endothelial-dependent vasorelaxation in aortic rings of rats. This vasorelaxation effect was attenuated by the Mas antagonist D-pro7-Ang-(1-7), and it was reduced in Mas knockout mice. These effects were associated with reduction in reactive oxygen species production. In addition, Ang II-induced reactive oxygen species production in human aortic endothelial cells was attenuated by preincubation with XNT. These results showed that chronic XNT administration improves the endothelial function of hypertensive and diabetic rat vessels by attenuation of the oxidative stress. Moreover, XNT elicits an endothelial-dependent vasorelaxation response, which was mediated by Mas. Thus, this study indicated that angiotensin-converting enzyme 2 activation promotes beneficial effects on the endothelial function and it is a potential target for treating cardiovascular disease.

A Novel Splice-Site Mutation in Angiotensin I-Converting Enzyme (ACE) Gene, c.3691+1G>A (IVS25+1G>A), Causes a Dramatic Increase in Circulating ACE through Deletion of the Transmembrane Anchor

PubMed Central

Persu, Alexandre; Lambert, Michel; Deinum, Jaap; Cossu, Marta; de Visscher, Nathalie; Irenge, Leonid; Ambroise, Jerôme; Minon, Jean-Marc; Nesterovitch, Andrew B.; Churbanov, Alexander; Popova, Isolda A.; Danilov, Sergei M.; Danser, A. H. Jan; Gala, Jean-Luc

2013-01-01

Background Angiotensin-converting enzyme (ACE) (EC 4.15.1) metabolizes many biologically active peptides and plays a key role in blood pressure regulation and vascular remodeling. Elevated ACE levels are associated with different cardiovascular and respiratory diseases. Methods and Results Two Belgian families with a 8-16-fold increase in blood ACE level were incidentally identified. A novel heterozygous splice site mutation of intron 25 - IVS25+1G>A (c.3691+1G>A) - cosegregating with elevated plasma ACE was identified in both pedigrees. Messenger RNA analysis revealed that the mutation led to the retention of intron 25 and Premature Termination Codon generation. Subjects harboring the mutation were mostly normotensive, had no left ventricular hypertrophy or cardiovascular disease. The levels of renin-angiotensin-aldosterone system components in the mutated cases and wild-type controls were similar, both at baseline and after 50 mg captopril. Compared with non-affected members, quantification of ACE surface expression and shedding using flow cytometry assay of dendritic cells derived from peripheral blood monocytes of affected members, demonstrated a 50% decrease and 3-fold increase, respectively. Together with a dramatic increase in circulating ACE levels, these findings argue in favor of deletion of transmembrane anchor, leading to direct secretion of ACE out of cells. Conclusions We describe a novel mutation of the ACE gene associated with a major familial elevation of circulating ACE, without evidence of activation of the renin-angiotensin system, target organ damage or cardiovascular complications. These data are consistent with the hypothesis that membrane-bound ACE, rather than circulating ACE, is responsible for Angiotensin II generation and its cardiovascular consequences. PMID:23560051

Possible identity of IL-8 converting enzyme in human fibroblasts as a cysteine protease.

PubMed

Ohashi, Kensaku; Sano, Emiko; Nakaki, Toshio; Naruto, Masanobu

2003-04-01

A converting activity was characterized in human diploid fibroblasts, which secrete 72IL-8 and 77IL-8 in treatment with IFN-beta and poly I: poly C. 77IL-8 was significantly converted to 72IL-8 by a partially purified fraction of the culture supernatant of human diploid fibroblasts. The converting activity, which was temperature-dependent and optimal at pH 6, was completely inhibited by cysteine protease inhibitors, antipain dihydrochloride and E-64, but not by other types of protease inhibitors. These data clearly show that human diploid fibroblasts are capable of processing IL-8 to produce a mature IL-8 and that the putative converting enzyme appears to be a cysteine protease.

Dissecting enzyme function with microfluidic-based deep mutational scanning.

PubMed

Romero, Philip A; Tran, Tuan M; Abate, Adam R

2015-06-09

Natural enzymes are incredibly proficient catalysts, but engineering them to have new or improved functions is challenging due to the complexity of how an enzyme's sequence relates to its biochemical properties. Here, we present an ultrahigh-throughput method for mapping enzyme sequence-function relationships that combines droplet microfluidic screening with next-generation DNA sequencing. We apply our method to map the activity of millions of glycosidase sequence variants. Microfluidic-based deep mutational scanning provides a comprehensive and unbiased view of the enzyme function landscape. The mapping displays expected patterns of mutational tolerance and a strong correspondence to sequence variation within the enzyme family, but also reveals previously unreported sites that are crucial for glycosidase function. We modified the screening protocol to include a high-temperature incubation step, and the resulting thermotolerance landscape allowed the discovery of mutations that enhance enzyme thermostability. Droplet microfluidics provides a general platform for enzyme screening that, when combined with DNA-sequencing technologies, enables high-throughput mapping of enzyme sequence space.

Ontogenetic role of angiontensin-converting enzyme in rats: thirst and sodium appetite evaluation.

PubMed

Mecawi, André S; Araujo, Iracema G; Rocha, Fábio F; Coimbra, Terezila M; Antunes-Rodrigues, José; Reis, Luís C

2010-01-12

We investigated the influence of captopril (an angiotensin converting enzyme inhibitor) treatment during pregnancy and lactation period on hydromineral balance of the male adult offspring, particularly, concerning thirst and sodium appetite. We did not observe significant alterations in basal hydromineral (water intake, 0.3M NaCl intake, volume and sodium urinary concentration) or cardiovascular parameters in adult male rats perinatally treated with captopril compared to controls. However, male offspring rats that perinatally exposed to captopril showed a significant attenuation in water intake induced by osmotic stimulation, extracellular dehydration and beta-adrenergic stimulation. Moreover, captopril treatment during perinatal period decreased the salt appetite induced by sodium depletion. This treatment also attenuated thirst and sodium appetite aroused during inhibition of peripheral angiotensin II generation raised by low concentration of captopril in the adult offspring. Interestingly, perinatal exposure to captopril did not alter water or salt intake induced by i.c.v. administration of angiotensin I or angiotensin II. These results showed that chronic inhibition of angiotensin converting enzyme during pregnancy and lactation modifies the regulation of induced thirst and sodium appetite in adulthood.

Endothelin-converting enzyme-1 degrades internalized somatostatin-14.

PubMed

Roosterman, Dirk; Kempkes, Cordula; Cottrell, Graeme S; Padilla, Benjamin E; Bunnett, Nigel W; Turck, Christoph W; Steinhoff, Martin

2008-05-01

Agonist-induced internalization of somatostatin receptors (ssts) determines subsequent cellular responsiveness to peptide agonists and influences sst receptor scintigraphy. To investigate sst2A trafficking, rat sst2A tagged with epitope was expressed in human embryonic kidney cells and tracked by antibody labeling. Confocal microscopical analysis revealed that stimulation with sst and octreotide induced internalization of sst2A. Internalized sst2A remained sequestrated within early endosomes, and 60 min after stimulation, internalized sst2A still colocalized with beta-arrestin1-enhanced green fluorescence protein (EGFP), endothelin-converting enzyme-1 (ECE-1), and rab5a. Internalized (125)I-Tyr(11)-SST-14 was rapidly hydrolyzed by endosomal endopeptidases, with radioactive metabolites being released from the cell. Internalized (125)I-Tyr(1)-octreotide accumulated as an intact peptide and was released from the cell as an intact peptide ligand. We have identified ECE-1 as one of the endopeptidases responsible for inactivation of internalized SST-14. ECE-1-mediated cleavage of SST-14 was inhibited by the specific ECE-1 inhibitor, SM-19712, and by preventing acidification of endosomes using bafilomycin A(1). ECE-1 cleaved SST-14 but not octreotide in an acidic environment. The metallopeptidases angiotensin-1 converting enzyme and ECE-2 did not hydrolyze SST-14 or octreotide. Our results show for the first time that stimulation with SST-14 and octreotide induced sequestration of sst2A into early endosomes and that endocytosed SST-14 is degraded by endopeptidases located in early endosomes. Furthermore, octreotide was not degraded by endosomal peptidases and was released as an intact peptide. This mechanism may explain functional differences between octreotide and SST-14 after sst2A stimulation. Moreover, further investigation of endopeptidase-regulated trafficking of neuropeptides may result in novel concepts of neuropeptide receptor inactivation in cancer diagnosis.

Endothelin-Converting Enzyme-1 Degrades Internalized Somatostatin-14

PubMed Central

Roosterman, Dirk; Kempkes, Cordula; Cottrell, Graeme S.; Padilla, Benjamin E.; Bunnett, Nigel W.; Turck, Christoph W.; Steinhoff, Martin

2008-01-01

Agonist-induced internalization of somatostatin receptors (ssts) determines subsequent cellular responsiveness to peptide agonists and influences sst receptor scintigraphy. To investigate sst2A trafficking, rat sst2A tagged with epitope was expressed in human embryonic kidney cells and tracked by antibody labeling. Confocal microscopical analysis revealed that stimulation with sst and octreotide induced internalization of sst2A. Internalized sst2A remained sequestrated within early endosomes, and 60 min after stimulation, internalized sst2A still colocalized with β-arrestin1-enhanced green fluorescence protein (EGFP), endothelin-converting enzyme-1 (ECE-1), and rab5a. Internalized 125I-Tyr11-SST-14 was rapidly hydrolyzed by endosomal endopeptidases, with radioactive metabolites being released from the cell. Internalized 125I-Tyr1-octreotide accumulated as an intact peptide and was released from the cell as an intact peptide ligand. We have identified ECE-1 as one of the endopeptidases responsible for inactivation of internalized SST-14. ECE-1-mediated cleavage of SST-14 was inhibited by the specific ECE-1 inhibitor, SM-19712, and by preventing acidification of endosomes using bafilomycin A1. ECE-1 cleaved SST-14 but not octreotide in an acidic environment. The metallopeptidases angiotensin-1 converting enzyme and ECE-2 did not hydrolyze SST-14 or octreotide. Our results show for the first time that stimulation with SST-14 and octreotide induced sequestration of sst2A into early endosomes and that endocytosed SST-14 is degraded by endopeptidases located in early endosomes. Furthermore, octreotide was not degraded by endosomal peptidases and was released as an intact peptide. This mechanism may explain functional differences between octreotide and SST-14 after sst2A stimulation. Moreover, further investigation of endopeptidase-regulated trafficking of neuropeptides may result in novel concepts of neuropeptide receptor inactivation in cancer diagnosis. PMID:18276747

Angiotensin I-converting enzyme inhibitors potentiate bradykinin's inotropic effects independently of blocking its inactivation.

PubMed

Minshall, R D; Erdös, E G; Vogel, S M

1997-08-04

The positive inotropic effects of bradykinin (BK) and 2 analogs resistant to angiotensin I-converting enzyme (ACE) were potentiated on isolated guinea pig atrial preparations by enalaprilat. The stable BK analogs, dextran-BK and [Hyp3-Tyr(Me)8]-BK, were as active as BK. Pretreatment for 5 min with enalaprilat augmented the maximal positive inotropic effect of [Hyp3-Tyr(Me)8]-BK 2.8-fold, from 19% to 53% and that of BK from 28% to 42% over baseline; inotropic responses to dextran-BK (1 microM) were similarly increased. The activity of atrial ACE, a zinc-requiring enzyme, was completely inhibited by 8-hydroxyquinoline-5-sulfonic acid (QSA, 10 mM), which raised the maximal inotropic effect of BK to 39% above baseline. This value rose to 67% when in addition to QSA, 1 microM enalaprilat was added; enalaprilat thus, potentiated the effects of BK independently of enzyme inhibition. The positive inotropic effects to BK and its analogs decline with time in the presence of these agonists. After 10 min of exposure, the response to 1 microM [Hyp3-Tyr(Me)8]-BK decreased to about half, and after 20 min, to 0. Enalaprilat, when present in the tissue bath, prevented the decline in inotropy; even after tachyphylaxis occurred, it reversed this decrease in activity when added. The effects of 1 microM [Hyp3-Tyr(Me)8]-BK, in the absence or presence of enalaprilat, were abolished by the BK B2 receptor antagonist icatibant (0.75 microM). The results indicate that ACE inhibitors, by potentiating the BK effects and blocking BK B2-receptor desensitization, may contribute to the beneficial cardiac effects of BK independently of blocking its inactivation.

Tissue Specificity of Human Angiotensin I-Converting Enzyme

PubMed Central

Kryukova, Olga V.; Tikhomirova, Victoria E.; Golukhova, Elena Z.; Evdokimov, Valery V.; Kalantarov, Gavreel F.; Trakht, Ilya N.; Schwartz, David E.; Dull, Randal O.; Gusakov, Alexander V.; Uporov, Igor V.; Kost, Olga A.; Danilov, Sergei M.

2015-01-01

Background Angiotensin-converting enzyme (ACE), which metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling, as well as in reproductive functions, is expressed as a type-1 membrane glycoprotein on the surface of endothelial and epithelial cells. ACE also presents as a soluble form in biological fluids, among which seminal fluid being the richest in ACE content - 50-fold more than that in blood. Methods/Principal Findings We performed conformational fingerprinting of lung and seminal fluid ACEs using a set of monoclonal antibodies (mAbs) to 17 epitopes of human ACE and determined the effects of potential ACE-binding partners on mAbs binding to these two different ACEs. Patterns of mAbs binding to ACEs from lung and from seminal fluid dramatically differed, which reflects difference in the local conformations of these ACEs, likely due to different patterns of ACE glycosylation in the lung endothelial cells and epithelial cells of epididymis/prostate (source of seminal fluid ACE), confirmed by mass-spectrometry of ACEs tryptic digests. Conclusions Dramatic differences in the local conformations of seminal fluid and lung ACEs, as well as the effects of ACE-binding partners on mAbs binding to these ACEs, suggest different regulation of ACE functions and shedding from epithelial cells in epididymis and prostate and endothelial cells of lung capillaries. The differences in local conformation of ACE could be the base for the generation of mAbs distingushing tissue-specific ACEs. PMID:26600189

High endothelin-converting enzyme-1 expression independently predicts poor survival of patients with esophageal squamous cell carcinoma.

PubMed

Wu, Ching-Fang; Lee, Ching-Tai; Kuo, Yao-Hung; Chen, Tzu-Haw; Chang, Chi-Yang; Chang, I-Wei; Wang, Wen-Lun

2017-09-01

Patients with esophageal squamous cell carcinoma have poor survival and high recurrence rate, thus an effective prognostic biomarker is needed. Endothelin-converting enzyme-1 is responsible for biosynthesis of endothelin-1, which promotes growth and invasion of human cancers. The role of endothelin-converting enzyme-1 in esophageal squamous cell carcinoma is still unknown. Therefore, this study investigated the significance of endothelin-converting enzyme-1 expression in esophageal squamous cell carcinoma clinically. We enrolled patients with esophageal squamous cell carcinoma who provided pretreated tumor tissues. Tumor endothelin-converting enzyme-1 expression was evaluated by immunohistochemistry and was defined as either low or high expression. Then we evaluated whether tumor endothelin-converting enzyme-1 expression had any association with clinicopathological findings or predicted survival of patients with esophageal squamous cell carcinoma. Overall, 54 of 99 patients with esophageal squamous cell carcinoma had high tumor endothelin-converting enzyme-1 expression, which was significantly associated with lymph node metastasis ( p = 0.04). In addition, tumor endothelin-converting enzyme-1 expression independently predicted survival of patients with esophageal squamous cell carcinoma, and the 5-year survival was poorer in patients with high tumor endothelin-converting enzyme-1 expression ( p = 0.016). Among patients with locally advanced and potentially resectable esophageal squamous cell carcinoma (stage II and III), 5-year survival was poorer with high tumor endothelin-converting enzyme-1 expression ( p = 0.003). High tumor endothelin-converting enzyme-1 expression also significantly predicted poorer survival of patients in this population. In patients with esophageal squamous cell carcinoma, high tumor endothelin-converting enzyme-1 expression might indicate high tumor invasive property. Therefore, tumor endothelin-converting enzyme-1 expression

Soybean phenolic-rich extracts inhibit key-enzymes linked to type 2 diabetes (α-amylase and α-glucosidase) and hypertension (angiotensin I converting enzyme) in vitro.

PubMed

Ademiluyi, Adedayo O; Oboh, Ganiyu

2013-03-01

This study sought to assess the inhibitory activities of phenolic-rich extracts from soybean on α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE) activities in vitro. The free phenolic extract of the soybean was obtained by extraction with 80% acetone, while that of the bound phenolic extract was done by extracting the alkaline and acid hydrolyzed residue with ethyl acetate. The inhibitory action of these extracts on the enzymes activity as well as their antioxidant properties was assessed. Both phenolic-rich extracts inhibited α-amylase, α-glucosidase and ACE enzyme activities in a dose dependent pattern. However, the bound phenolic extract exhibited significantly (P < 0.05) higher α-amylase and ACE inhibition while the free phenolic extract had significantly (P < 0.05) higher α-glucosidase inhibitory activity. Nevertheless, the free phenolic extract had higher α-glucosidase inhibitory activity when compared to that of α-amylase; this property confer an advantage on soybean phenolic-rich extracts over commercial antidiabetic drugs with little or no side effect. And inhibition of ACE suggests the antihypertension potential of soybean phenolic-rich extracts. Furthermore, the enzyme inhibitory activities of the phenolic-rich extracts were not associated with their phenolic content. Therefore, phenolic-rich extracts of soybean could inhibit key-enzyme linked to type 2 diabetes (α-amylase and α-glucosidase) and hypertension (ACE) and thus could explain in part the mechanism by which soybean renders these health promoting effect. Copyright © 2011 Elsevier GmbH. All rights reserved.

The importance of association between angiotensin-converting enzyme (ACE) Gene I/D polymorphism and diabetic peripheral neuropathy.

PubMed

Inanir, Ahmet; Basol, Nursah; Karakus, Nevin; Yigit, Serbulent

2013-11-10

Diabetic peripheral neuropathy (DPN) is a microvascular complication of diabetes mellitus (DM) due to decreasing quality of life. In the present study, it is aimed to evaluate angiotensin-converting enzyme (ACE) Gene I/D polymorphism in Turkish population. Two hundred and thirty-five DPN patients and two hundred and eighty-one controls were enrolled in this study. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR) analyses for the ACE gene I/D polymorphism. Baseline characteristics of the DPN patients according to ACE genotypes were similar, except for history of hypertension. The frequency of II genotype was significantly higher in patients with positive history of hypertension than the patients with negative history of hypertension (p=0.013). DD genotype of I/D polymorphism was found to be a susceptibility factor for DPN in homozygous form (p=0.032). According to allele frequencies, D allele of I/D polymorphism was found to be a susceptibility factor for DPN (p=0.031). ACE gene I/D polymorphism may research in DM patients to determine genetic predisposition for DPN. It can be useful for taking early measures and avoiding DPN in a Turkish population. © 2013 Elsevier B.V. All rights reserved.

Angiotensin converting enzyme inhibition and the kidney

NASA Technical Reports Server (NTRS)

Hollenberg, N. K.

1988-01-01

Angiotensin II (Ang II) induces a marked reduction in renal blood flow at doses well below those required to induce a pressor response, and as blood flow falls there is a decline in glomerular filtration rate and sodium excretion. This striking sensitivity of the renal blood supply led many workers to consider the possibility that angiotensin functions as a local renal hormone. As angiotensin converting enzyme (ACE) was found in particular abundance in the lung, it seemed reasonable to suspect that most of the conversion occurred there, and that the function of Ang II would be primarily systemic, rather than intrarenal. In this review, I will explore the evidence that has accumulated on these two possibilities, since they have important implications for our current understanding of normal kidney function and derangements of kidney function in disease.

Angiotensin converting enzyme insertion/deletion polymorphism: association with ethnic origin.

PubMed

Barley, J; Blackwood, A; Carter, N D; Crews, D E; Cruickshank, J K; Jeffery, S; Ogunlesi, A O; Sagnella, G A

1994-08-01

To determine the distribution of the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene in several ethnic groups: Caucasian Europeans, Black Nigerians, Samoan Polynesians and Yanomami Indians. The ratio of the frequencies of the II, ID and DD genotypes were 1:2:1 in the Europeans, but there was a tendency towards a higher frequency of the D allele in the Nigerians. In contrast, the Samoans and the Yanomami Indians displayed a much higher frequency of the I allele than of the D allele. The relationship between ACE genotype and disease in these latter groups is still not known, but the present results clearly suggest that ethnic origin should be carefully considered in the increasing number of studies on the association between I/D ACE genotype and disease aetiology.

The Use of Angiotensin-I Converting Enzyme I/D Genetic Polymorphism as a Biomarker of Athletic Performance in Humans

PubMed Central

De Mello Costa, Maria Fernanda; Slocombe, Ron

2012-01-01

Angiotensin II is a key regulator of blood pressure and cardiovascular function in mammals. The conversion of angiotensin into its active form is carried out by Angiotensin I-Converting Enzyme (ACE). The measurement of ACE concentration in plasma or serum, its enzymatic activity, and the correlation between an insertion/deletion (I/D) genetic polymorphism of the ACE gene have been investigated as possible indicators of superior athletic performance in humans. In this context, other indicators of superior adaptation to exercise resulting in better athletic performance (such as ventricular hypertrophy, VO2 max, and competition results) were mostly used to study the association between ACE I/D polymorphism and improved performance. Despite the fact that the existing literature presents little consensus, there is sufficient scientific evidence to warrant further investigation on the usage of ACE activity and the I/D ACE gene polymorphism as biomarkers of superior athletic performance in humans of specific ethnicities or in athletes involved in certain sports. In this sense, a biomarker would be a substance or genetic component that could be measured to provide a degree of certainty, or an indication, of the presence of a certain trait or characteristic that would be beneficial to the athlete’s performance. Difficulties in interpreting and comparing the results of scientific research on the topic arise from dissimilar protocols and variation in study design. This review aims to investigate the current literature on the use of ACE I/D polymorphism as a biomarker of performance in humans through the comparison of scientific publications. PMID:25586030

The use of Angiotensin-I converting enzyme i/d genetic polymorphism as a biomarker of athletic performance in humans.

PubMed

De Mello Costa, Maria Fernanda; Slocombe, Ron

2012-10-09

Angiotensin II is a key regulator of blood pressure and cardiovascular function in mammals. The conversion of angiotensin into its active form is carried out by Angiotensin I-Converting Enzyme (ACE). The measurement of ACE concentration in plasma or serum, its enzymatic activity, and the correlation between an insertion/deletion (I/D) genetic polymorphism of the ACE gene have been investigated as possible indicators of superior athletic performance in humans. In this context, other indicators of superior adaptation to exercise resulting in better athletic performance (such as ventricular hypertrophy, VO2 max, and competition results) were mostly used to study the association between ACE I/D polymorphism and improved performance. Despite the fact that the existing literature presents little consensus, there is sufficient scientific evidence to warrant further investigation on the usage of ACE activity and the I/D ACE gene polymorphism as biomarkers of superior athletic performance in humans of specific ethnicities or in athletes involved in certain sports. In this sense, a biomarker would be a substance or genetic component that could be measured to provide a degree of certainty, or an indication, of the presence of a certain trait or characteristic that would be beneficial to the athlete's performance. Difficulties in interpreting and comparing the results of scientific research on the topic arise from dissimilar protocols and variation in study design. This review aims to investigate the current literature on the use of ACE I/D polymorphism as a biomarker of performance in humans through the comparison of scientific publications.

Rediscovering ACE: Novel insights into the many roles of the angiotensin-converting enzyme

PubMed Central

Gonzalez-Villalobos, Romer A.; Shen, Xiao Z.; Bernstein, Ellen A.; Janjulia, Tea; Taylor, Brian; Giani, Jorge F.; Blackwell, Wendell-Lamar B.; Shah, Kandarp H.; Shi, Peng D.; Fuchs, Sebastien; Bernstein, Kenneth E.

2013-01-01

Angiotensin converting enzyme (ACE) is best known for the catalytic conversion of angiotensin I to angiotensin II. However, the use of gene-targeting techniques has led to mouse models highlighting many other biochemical properties and actions of this enzyme. This review discusses recent studies examining the functional significance of ACE tissue-specific expression and the presence in ACE of two independent catalytic sites with distinct substrates and biological effects. It is these features which explain why ACE makes important contributions to many different physiological processes including renal development, blood pressure control, inflammation and immunity. PMID:23686164

Cholecystokinin-converting enzymes in brain.

PubMed Central

Malesci, A; Straus, E; Yalow, R S

1980-01-01

Crude extracts of porcine cerebral cortical tissue convert cholecystokinin (CCK) to its COOH-terminal fragments, the dodecapeptide (CCK-12) and the octapeptide (CCK-8). The Sephadex G-75 void volume eluate of the crude extract cleaves the arginine-isoleucine bond and effects conversion only to CCK-12; the Sephadex G-50 void volume eluate of the same extract cleaves the arginine-aspartate bond as well, so that both CCK-12 and CCK-8 are end products. Thus, there are at least two enzymes; the one involved in the conversion to CCK-12 is of larger molecular radius than the other. The Km for the cleavage of CCK at the arginine-isoleucine bond by the Sephadex G-75 void volume eluate enzyme is 1.1 X 10(-6) M; the Km for trypsin cleavage of the same bond is 4.7 x 10(-6) M. The lower Vmax for the brain enzyme (1.5 x 10(-11) mol/min per g of extract) compared with trypsin (66 x 10(-11) mol/min per g of trypsin) simply reflects the lesser degree of purify of the brain extract than of the highly purified trypsin. Images PMID:6987659

Active peptides from skate (Okamejei kenojei) skin gelatin diminish angiotensin-I converting enzyme activity and intracellular free radical-mediated oxidation.

PubMed

Ngo, Dai-Hung; Ryu, BoMi; Kim, Se-Kwon

2014-01-15

Skin gelatin of skate (Okamejei kenojei) was hydrolyzed using Alcalase, flavourzyme, Neutrase and protamex. It was found that the Alcalase hydrolysate exhibited the highest angiotensin-I converting enzyme (ACE) inhibitory activity. Then, Alcalase hydrolysate was further hydrolyzed with protease and separated by an ultrafiltration membrane system. Finally, two peptides responsible for ACE inhibitory activity were identified to be MVGSAPGVL (829Da) and LGPLGHQ (720Da), with IC50 values of 3.09 and 4.22μM, respectively. Moreover, the free radical-scavenging activity of the purified peptides was determined in human endothelial cells. In addition, the antioxidative mechanism of the purified peptides was evaluated by protein and gene expression levels of antioxidant enzymes. The current study demonstrated that the peptides derived from skate skin gelatin could be used in the food industry as functional ingredients with potent antihypertensive and antioxidant benefits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Separation and Characterization of Angiotensin I Converting Enzyme (ACE) Inhibitory Peptides from Saurida elongata Proteins Hydrolysate by IMAC-Ni2.

PubMed

Sun, Lixia; Wu, Shanguang; Zhou, Liqin; Wang, Feng; Lan, Xiongdiao; Sun, Jianhua; Tong, Zhangfa; Liao, Dankui

2017-02-15

Lizard fish protein hydrolysates (LFPH) were prepared from Lizard fish ( Saurida elongata ) proteins possessing powerful angiotensin I converting enzyme (ACE) inhibitory activity and the fraction (LFPH-I) with high ACE inhibitory activity was obtained through ultrafiltration. The active Fraction (F2) was isolated from LFPH-I using immobilized metal affinity chromatography (IMAC - Ni 2+ ). Analysis of amino acid levels revealed that F2 eluted from IMAC was enriched in Met, His, Tyr, Pro, Ile, and Leu compared to the crude peptide LFPH-I. F2 with the high ACE inhibitory activity (IC 50 of 0.116 mg·mL -1 ) was further separated by a reverse-phase column to yield a novel ACE inhibitory peptide with IC 50 value of 52 μM. The ACE inhibitory peptide was identified as Arg-Tyr-Arg-Pro, RYRP. The present study demonstrated that IMAC may be a useful tool for the separation of ACE inhibitory peptides from protein hydrolysate.

Expression and regulation of estrogen-converting enzymes in ectopic human endometrial tissue.

PubMed

Fechner, Sabine; Husen, Bettina; Thole, Hubert; Schmidt, Markus; Gashaw, Isabella; Kimmig, Rainer; Winterhager, Elke; Grümmer, Ruth

2007-10-01

To investigate the regulation of estrogen-converting enzymes in human ectopic endometrial tissue. Animal study. Academic medical center. Sixty female nude mice with implanted human endometrial tissue. Twenty-two premenopausal women undergoing endometrial biopsy or hysterectomy. Human endometrial tissue was implanted into the peritoneal cavity of nude mice, and the effect of therapeutic drugs on transcription of steroid receptors and estrogen-converting enzymes was analyzed. Transcript levels of steroid hormone receptors, 17beta-hydroxysteroid dehydrogenase type 1 and 2, aromatase, and steroid sulfatase as well as proliferation rate were analyzed in the human ectopic endometrial tissue. Steroid receptors and estrogen-converting enzymes were expressed in the ectopic human endometrial fragments. Application of medroxyprogesterone acetate, dydrogesterone, danazol, and the aromatase inhibitor finrozole significantly inhibited aromatase transcription. In addition, danazol caused a significant decrease in transcription of steroid sulfatase, and finrozole, of 17beta-hydroxysteroid dehydrogenase type 1 in parallel to a decrease in proliferation rate in the ectopic human endometrial tissue. Pharmacological regulation of transcription of estrogen-converting enzymes in human endometrium cultured in nude mice may help to develop new therapeutic concepts based on local regulation of estrogen metabolism in endometriosis.

Is substance P released from slices of the rat spinal cord inactivated by peptidase(s) distinct from both 'enkephalinase' and 'angiotensin-converting enzyme'?

PubMed

Mauborgne, A; Bourgoin, S; Benoliel, J J; Hamon, M; Cesselin, F

1991-02-25

Studies on the effects of peptidase inhibitors on substance P-like immunoreactive material (SPLI) released by K(+)-induced depolarization from slices of the rat spinal cord showed that bacitracin was the most potent agent to protect SPLI from degradation. Captopril and thiorphan which inhibit, respectively, angiotensin I converting enzyme and endopeptidase-24.11 also protected SPLI from degradation. However other inhibitors of these two enzymes, kelatorphan for endopeptidase-24.11 and enalaprilat for angiotensin I converting enzyme were essentially inactive, indicating that both enzymes are probably not involved in the degradation of endogenous substance P. Instead, the non-additive protecting effect of bacitracin, captopril and thiorphan might be due to the blockade of some 'bacitracin-sensitive enzyme' playing a key role in the catabolism of SP within the rat spinal cord.

Optimization of Bromelain-Aided Production of Angiotensin I-Converting Enzyme Inhibitory Hydrolysates from Stone Fish Using Response Surface Methodology.

PubMed

Muhammad Auwal, Shehu; Zarei, Mohammad; Abdul-Hamid, Azizah; Saari, Nazamid

2017-03-31

The stone fish is an under-utilized sea cucumber with many nutritional and ethno-medicinal values. This study aimed to establish the conditions for its optimum hydrolysis with bromelain to generate angiotensin I-converting enzyme (ACE)-inhibitory hydrolysates. Response surface methodology (RSM) based on a central composite design was used to model and optimize the degree of hydrolysis (DH) and ACE-inhibitory activity. Process conditions including pH (4-7), temperature (40-70 °C), enzyme/substrate (E/S) ratio (0.5%-2%) and time (30-360 min) were used. A pH of 7.0, temperature of 40 °C, E/S ratio of 2% and time of 240 min were determined using a response surface model as the optimum levels to obtain the maximum ACE-inhibitory activity of 84.26% at 44.59% degree of hydrolysis. Hence, RSM can serve as an effective approach in the design of experiments to improve the antihypertensive effect of stone fish hydrolysates, which can thus be used as a value-added ingredient for various applications in the functional foods industries.

Single-domain angiotensin I converting enzyme (kininase II): characterization and properties.

PubMed

Deddish, P A; Wang, L X; Jackman, H L; Michel, B; Wang, J; Skidgel, R A; Erdös, E G

1996-12-01

Somatic angiotensin I converting enzyme (ACE; kininase II) has two active sites, in two (N and C) domains. We studied the active centers with separate N-domain ACE (N-ACE), testicular C-domain ACE (germinal ACE) and, as control, renal somatic ACE. Germinal ACE cleaved the nonapeptide bradykinin about two times faster than N-ACE in 20 mM Cl-. Bradykinin1-7 was hydrolyzed further to bradykinin1-5 by N-ACE four times faster in the absence of Cl-, but at 300 mM Cl- the C-domain hydrolyzed it twice as fast. The hematopoietic system regulatory peptide acetyl-Ser-Asp-Lys-Pro was split to two dipeptides by N-ACE, depending on the chloride concentration, 8 to 24 times faster than by germinal ACE; at 100 mM Cl-, the Kcat with N-ACE was eight times higher. One millimolar 1-fluoro-2,4-dinitrobenzene inhibited germinal ACE 96% but it inhibited N-ACE by only 31%. [3H]Ramiprilat was displaced by other unlabeled ACE inhibitors to establish their relative affinities. Captopril had the lowest IC50 (0.5 nM) with N-ACE and the highest IC50 (8.3 nM) with the germinal ACE. The IC50 values of ramiprilat and quinaprilat were about the same with both active sites. The association and dissociation constants of [3H]ramiprilat indicated faster association with and faster dissociation from N-ACE than from germinal ACE. After exposure to alkali or moderate heat, somatic ACE was cleaved by plasmin and kallikrein, releasing N-ACE and apparently inactivating the C-domain. These studies affirm the differences in the activity, stability and inhibition of the two active sites of ACE.

The granulocyte-angiotensin system. Angiotensin I-converting activity of cathepsin G.

PubMed

Klickstein, L B; Kaempfer, C E; Wintroub, B U

1982-12-25

Cathepsin G, an Mr = 26,000-29,000 cationic human neutrophil lysosomal serine protease, releases angiotensin II from angiotensinogen and was, therefore, examined for angiotensin I-converting activity. Cathepsin G-dependent angiotensin I conversion was detected by a high performance liquid chromatography assay which permitted independent quantitation of angiotensin I and angiotensin II and detection of angiotensin degradation products. 1.8-5.0 X 10(-9) M cathepsin G converted angiotensin I (3.3 X 10(-4) M) to angiotensin II without further degradation of angiotensin II. The pH optimum for cathepsin G-catalyzed angiotensin I conversion was pH 7.0-7.5, and the Km and Kcat were 2.2 X 10(-4) M and 3.4 s-1, respectively. In contrast to dipeptidyl hydrolase-converting enzyme, cathepsin G did not inactivate bradykinin, did not cleave hippuryl-His-Leu, and was not inhibited by 10(-4) M Captopril or SQ 20881. Purified human neutrophils stimulated with 2.5 X 10(-6) M-10(-10) M fMet-Leu-Phe released angiotensin-converting activity with a Km of 3.3 X 10(-4) M. That the angiotensin-converting activity released from neutrophils was attributable to cathepsin G was indicated by similar susceptibility to inhibitors and adsorption by goat antibody to cathepsin G. The granulocyte-angiotensin system provides a mechanism for the local generation of angiotensin II at sites of neutrophil accumulation and may be of significance in regulation of blood flow in tissue microvasculature.

Mucopolysaccharidosis type I: Identification and characterization of mutations affecting alpha-L-iduronidase activity.

PubMed

Lee-Chen, Guey-Jen; Lin, Shuan-Pei; Chen, I-Shen; Chang, Jui-Hung; Yang, Chyau-Wen; Chin, Yi-Wen

2002-06-01

Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of the lysosomal enzyme alpha-L-iduronidase (IDUA). MPS I covers a broad spectrum of clinical severity ranging from severe Hurler syndrome through intermediate Hurler/Scheie syndrome to mild Scheie syndrome. Mutation screening was performed in two unrelated Taiwanese MPS I patients. A Hurler/Scheie patient had A79V (C to T transition in codon 79) in exon 2 and R619G (C to G transversion in codon 619) in exon 14. R619G has been shown to cause disease. Expression of A79V in COS-7 cells showed trace amounts of IDUA activity, demonstrating the deleterious nature of the mutation. A79V mutation did not cause a reduction in IDUA mRNA levels. The reduced level of IDUA protein suggests increased degradation of the mutant enzyme. A Hurler patient had 134del12 (in-frame deletion of codons 16-19 in signal peptide) in exon 1 and Q584X (C to T transition in codon 584) in exon 13. Transfection of COS-7 cells with Q584X did not yield active enzyme. Q584X mutation caused an apparent reduction in the IDUA mRNA level and no IDUA protein was detected. Conversely, 134del12 showed 124.6% of normal activity in transfected cells and a 77-kDa precursor protein was observed on Western blot, suggesting biologic activity of precursor IDUA without posttranslational cleavage. These findings provide further evidence of the molecular heterogeneity in mutations in MPS I.

Effect of the Angiotensin I Converting Enzyme Inhibitor, MK-421, on Experimentally Induced Drinking

NASA Technical Reports Server (NTRS)

Fregley, Melvin J.; Fater, Dennis C.; Greenleaf, John E.

1982-01-01

MK-421, the ethyl ester maleate salt of N-(S)-1-(ethoxycarbonyl)-3-phenyl-propyl- Ala-L-Pro, is an angiotensin I converting enzyme inhibitor. An initial objective was to determine whether MK-421, administered at 0, 2.5, 5.0, 10.0, 20.0 and 40.0 mg/kg, ip to 96 female rats 15 min prior to administration of the beta-adrenergic agonist, isoproterenol (25 microgram/kg, ip), would inhibit the drinking induced by isoproterenol during 2 h after its administration. The water intake induced by isoproterenol was inhibited significantly by 2.5 mg MK-421/kg. When a similar experiment was performed using Angiotensin I (AI) (200 microgram/kg, ip) as the dipsogenic agent, MK-421 (5 mg/kg, ip), administered 15 min prior to AI, inhibited significantly both the dipsogenic and the diuretic effect of AI. However, administration of angiotensin II (AII, 200 microgram/kg, ip) 15 min after MK-421 (5mg/kg) was accompanied by a water intake that did not differ from AII alone. The drink induced by ip administration of 1.0 m NaCl solution (1% of body wt, ip) was not inhibited by administration of MK-421 (5 mg/kg) 15 min prior to allowing access to water while the drink induced by a 24 h dehydration was partially inhibited. Thus, the drinks induced by administraition of either isoproterenol or AI are dependent on formation of AII. That induced by dehydration is partially dependent, while that induced by hypertonic siilinc is independent of the formation of AII.

Empirical and bioinformatic characterization of buffalo (Bubalus bubalis) colostrum whey peptides & their angiotensin I-converting enzyme inhibition.

PubMed

Ashok, N R; Aparna, H S

2017-08-01

Whey based peptides are well known for their nutritional and multifunctional properties. In this context, whey proteins from buffalo colostrum & milk were digested by in vitro simulation digestion and analyzed by nano-LC-MS/MS. Functional protein association networks, gene annotations and localization of identified proteins were carried out. An ACE inhibitory peptide sorted from the library was custom synthesized and an in vitro ACE assay was performed. The study led to the identification of 74 small peptides which were clustered into 5 gene functional groups and majority of them were secretory proteins. Among the identified peptides, majority of them were found identical to angiotensin I-converting enzyme (ACE) inhibitors, antioxidant, antimicrobial, immunomodulatory and opioidal peptides. An octapeptide (m/z - 902.51, IQKVAGTW) synthesized was found to inhibit ACE with an IC 50 of 300±2µM. The present investigation thus establishes newer vista for food derived peptides having ACE inhibitory potential for nutraceutical or therapeutic applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Porcine pulmonary angiotensin I-converting enzyme--biochemical characterization and spatial arrangement of the N- and C-domains by three-dimensional electron microscopic reconstruction.

PubMed

Chen, Hui-Ling; Lünsdorf, Heinrich; Hecht, Hans-Jürgen; Tsai, Hsin

2010-08-01

The somatic angiotensin I-converting enzyme (sACE; peptidyl-dipeptidase A; EC 3.4.15.1) was isolated from pig lung and purified to homogeneity. The purified enzyme has a molecular mass of about 180 kDa. Upon proteolytic cleavage, two approximately 90 kDa fragments were obtained and identified by amino-terminal sequence analysis as the N- and C-domains of sACE. Both purified domains were shown to be catalytically active. A 2.3 nm resolution model of sACE was obtained by three-dimensional electron microscopic reconstruction of negatively stained sACE particles, based on atomic X-ray data fitting. Our model shows for the first time the relative orientation of the sACE catalytically active domains and their spatial distance. (c) 2010 Elsevier Ltd. All rights reserved.

Cardiomyopathy mutations reveal variable region of myosin converter as major element of cross-bridge compliance.

PubMed

Seebohm, B; Matinmehr, F; Köhler, J; Francino, A; Navarro-Lopéz, F; Perrot, A; Ozcelik, C; McKenna, W J; Brenner, B; Kraft, T

2009-08-05

The ability of myosin to generate motile forces is based on elastic distortion of a structural element of the actomyosin complex (cross-bridge) that allows strain to develop before filament sliding. Addressing the question, which part of the actomyosin complex experiences main elastic distortion, we suggested previously that the converter domain might be the most compliant region of the myosin head domain. Here we test this proposal by studying functional effects of naturally occurring missense mutations in the beta-myosin heavy chain, 723Arg --> Gly (R723G) and 736Ile --> Thr (I736T), in comparison to 719Arg --> Trp (R719W). All three mutations are associated with hypertrophic cardiomyopathy and are located in the converter region of the myosin head domain. We determined several mechanical parameters of single skinned slow fibers isolated from Musculus soleus biopsies of hypertrophic cardiomyopathy patients and healthy controls. Major findings of this study for mutation R723G were i), a >40% increase in fiber stiffness in rigor with a 2.9-fold increase in stiffness per myosin head (S( *)(rigor R723G) = 0.84 pN/nm S( *)(rigor WT) = 0.29 pN/nm); and ii), a significant increase in force per head (F( *)(10 degrees C), 1.99 pN vs. 1.49 pN = 1.3-fold increase; F( *)(20 degrees C), 2.56 pN vs. 1.92 pN = 1.3-fold increase) as well as stiffness per head during isometric steady-state contraction (S( *)(active10 degrees C), 0.52 pN/nm vs. 0.28 pN/nm = 1.9-fold increase). Similar changes were found for mutation R719W (2.6-fold increase in S( *)(rigor); 1.8-fold increase in F( *)(10 degrees C), 1.6-fold in F( *)(20 degrees C); twofold increase in S( *)(active10 degrees C)). Changes in active cross-bridge cycling kinetics could not account for the increase in force and active stiffness. For the above estimates the previously determined fraction of mutated myosin in the biopsies was taken into account. Data for wild-type myosin of slow soleus muscle fibers support previous

Demonstration of extrapulmonary activity of angiotensin converting enzyme in intact tissue preparations.

PubMed Central

Lembeck, F.; Griesbacher, T.; Eckhardt, M.

1990-01-01

1. The activity of angiotensin converting enzyme (ACE) has been studied on functional parameters of intact isolated preparations of extrapulmonary tissues. The conversion of angiotensin I (A I) to angiotensin II (A II) and the cleavage of bradykinin (BK) were used as indicators of ACE activity. Captopril was employed as a specific inhibitor of ACE. 2. Captopril augmented the BK-induced contractions of the rat isolated uterus, the BK- and substance P-induced contractions of the guinea-pig ileum, and the BK-induced venoconstriction in the isolated perfused ear of the rabbit. Degradation of BK by ACE was calculated to be 52% in the rat uterus and 75% in the rabbit perfused ear. 3. Captopril inhibited the A I-induced contractions of the rat isolated colon, the A I-induced vasoconstriction in the isolated perfused ear of the rabbit and the rise in blood pressure induced by i.a. injections of A I in pithed rats. Conversion of A I to A II was calculated to be 13% in the rat colon and 26% in the rabbit perfused ear. 4. From estimations of the A II activity (bioassay on the rat colon) in the effluent of the perfused ear of the rabbit after injections of A I into the arterial inflow cannula it was calculated that approximately one tenth of A I was converted to A II during a single passage through the ear (less than 15 s).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2164861

Tumor necrosis factor alpha converting enzyme: an encouraging target for various inflammatory disorders.

PubMed

Bahia, Malkeet S; Silakari, Om

2010-05-01

Tumor necrosis factor alpha is one of the most common pro-inflammatory cytokines responsible for various inflammatory disorders. It plays an important role in the origin and progression of rheumatoid arthritis and also in other autoimmune disease conditions. Some anti-tumor necrosis factor alpha antibodies like Enbrel, Humira and Remicade have been successfully used in these disease conditions as antagonists of tumor necrosis factor alpha. Inhibition of generation of active form of tumor necrosis factor alpha is a promising therapy for various inflammatory disorders. Therefore, the inhibition of an enzyme (tumor necrosis factor alpha converting enzyme), which is responsible for processing inactive form of tumor necrosis factor alpha into its active soluble form, is an encouraging target. Many tumor necrosis factor alpha converting enzyme inhibitors have been the candidates of clinical trials but none of them have reached in to the market because of their broad spectrum inhibitory activity for other matrix metalloproteases. Selectivity of tumor necrosis factor alpha converting enzyme inhibition over matrix metalloproteases is of utmost importance. If selectivity is achieved successfully, side-effects can be over-ruled and this approach may become a novel therapy for treatment of rheumatoid arthritis and other inflammatory disorders. This cytokine not only plays a pivotal role in inflammatory conditions but also in some cancerous conditions. Thus, successful targeting of tumor necrosis factor alpha converting enzyme may result in multifunctional therapy.

Antioxidative sulphated polygalactans from marine macroalgae as angiotensin-I converting enzyme inhibitors.

PubMed

Makkar, Fasina; Chakraborty, Kajal

2017-08-17

Antioxidant and antihypertensive potential of the sulphated polygalactans isolated from the marine macroalgae Kappaphycus alvarezii and Gracilaria opuntia were assessed by utilising different in vitro systems. The galactans isolated from K. alvarezii possessed significantly greater antioxidative properties as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH IC 90 0.97 mg/mL) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS .+ IC 90 0.72 mg/mL) scavenging activities than those isolated from G. opuntia (DPPH IC 90 1.2 mg/mL and ABTS 0.86 mg/mL). The sulphated polygalactan →4)-4-O-sulphonato-(2-O-methyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-methyl)-α-D-galactopyranan from K. alvarezii showed greater angiotensin-I-converting enzyme (ACE) inhibitory activity (IC 50 0.02 μg/mL) than →3)-4-O-sulphonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulphonato)-α-D-galactopyranosyl-(1→3)-4-O-sulphonato-(6-O-acetyl)-β-D-xylosyl-(1→3)-4-O-sulphonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulphonato)-α-D-galactopyranan motif extracted from G. opuntia (IC 50 0.70 μg/mL). Structure activity correlation studies displayed that the ACE inhibitory properties of titled polygalactans were directly proportional to their electronic properties and inversely with the steric and hydrophobic characteristics. Putative ACE inhibitory mechanism of action of sulphated galactans from marine macroalgae corroborated the structure bioactivity correlation analysis.

Changes of Serum Angiotensin-Converting Enzyme Activity During Treatment of Patients with Graves’ Disease*

PubMed Central

Lee, Dong Soo; Chung, June-Key; Cho, Bo Youn; Koh, Chang-Soon; Lee, Munho

1986-01-01

Serum angiotensin-converting enzyme activity was measured spectrophotometrically, and serum thyrotropin-binding-inhibitory immunoglobulin (TBII) activity was measured by radioreceptor assay in normal subjects and in patients with Graves’ disease serially before and during treatment, and these activities were compared with each other and with thyroid hormone levels in various thyroid functional status. Correlation between serum angiotensin-converting enzyme activity and serum thyroid hormone level was pursued with relation to the changes of thyroid functional status in patients with Graves’ disease during treatment. Serum angiotensin-converting enzyme activity was significantly elevated in patients with hyperthyroid Graves’ disease before the start of treatment (35 ± 13 nmol/min/ml, n=50), and not in patients with Graves’ disease, euthyroid state during treatment with antithyroid drugs or radioactive iodine (23 ± 9 nmol/min/ml, n=12), but decreased significantly in patients with Graves’ disease, hypothyroid state transiently during treatment (15 ± 4 nmol/min/ml, n=12), respectively in comparison with normal control subjects. Serum angiotensin-converting enzyme activity was positively correlated with the log value of serum T3 concentration (r=0.62, p<0.001, n=95), and with the log value of free thyroxine index (r=0.66, p<0.001, n=91) but not statistically significantly with serum TBII activity. Serum angiotensin-converting enzyme activity was followed in 11 patients with initially increased activity and the activity decreased in proportion to serum thyroid hormone level during treatment, irrespective of treatment modality. It is suggested that thyroid hormones play a role in the increase and decrease of serum angiotensin-converting enzyme activity directly or indirectly influencing the peripheral tissues (probably reticuloendothelial cells or peripheral endothelial cells) in patients with Graves’ disease. PMID:15759385

Optimization of Bromelain-Aided Production of Angiotensin I-Converting Enzyme Inhibitory Hydrolysates from Stone Fish Using Response Surface Methodology

PubMed Central

Auwal, Shehu Muhammad; Zarei, Mohammad; Abdul-Hamid, Azizah; Saari, Nazamid

2017-01-01

The stone fish is an under-utilized sea cucumber with many nutritional and ethno-medicinal values. This study aimed to establish the conditions for its optimum hydrolysis with bromelain to generate angiotensin I-converting enzyme (ACE)-inhibitory hydrolysates. Response surface methodology (RSM) based on a central composite design was used to model and optimize the degree of hydrolysis (DH) and ACE-inhibitory activity. Process conditions including pH (4–7), temperature (40–70 °C), enzyme/substrate (E/S) ratio (0.5%–2%) and time (30–360 min) were used. A pH of 7.0, temperature of 40 °C, E/S ratio of 2% and time of 240 min were determined using a response surface model as the optimum levels to obtain the maximum ACE-inhibitory activity of 84.26% at 44.59% degree of hydrolysis. Hence, RSM can serve as an effective approach in the design of experiments to improve the antihypertensive effect of stone fish hydrolysates, which can thus be used as a value-added ingredient for various applications in the functional foods industries. PMID:28362352

Soy Pulp Extract Inhibits Angiotensin I-Converting Enzyme (ACE) Activity In Vitro: Evidence for Its Potential Hypertension-Improving Action.

PubMed

Nishibori, Naoyoshi; Kishibuchi, Reina; Morita, Kyoji

2017-05-04

Soy pulp, called "okara" in Japanese, is known as a by-product of the production of bean curd (tofu), and expected to contain a variety of biologically active substances derived from soybean. However, the biological activities of okara ingredients have not yet been fully understood, and the effectiveness of okara as a functional food seems necessary to be further evaluated. Then the effect of okara extract on angiotensin I-converting enzyme (ACE) activity was examined in vitro, and the extract was shown to cause the inhibition of ACE activity in a manner depending on its concentration. Kinetic analysis indicated that this enzyme inhibition was accompanied by an increase in the Km value without any change in Vmax. Further studies suggested that putative inhibitory substances contained in the extract might be heat stable and dialyzable, and recovered mostly in the peptide fraction obtained by a spin-column separation and a high performance liquid chromatography (HPLC) fractionation. Therefore, the extract was speculated to contain small-size peptides responsible for the inhibitory effect of okara extract on ACE activity, and could be expected to improve the hypertensive conditions by reducing the production of hypertensive peptide.

Quantitative Structure-Activity Relationship Modeling Coupled with Molecular Docking Analysis in Screening of Angiotensin I-Converting Enzyme Inhibitory Peptides from Qula Casein Hydrolysates Obtained by Two-Enzyme Combination Hydrolysis.

PubMed

Lin, Kai; Zhang, Lanwei; Han, Xue; Meng, Zhaoxu; Zhang, Jianming; Wu, Yifan; Cheng, Dayou

2018-03-28

In this study, Qula casein derived from yak milk casein was hydrolyzed using a two-enzyme combination approach, and high angiotensin I-converting enzyme (ACE) inhibitory activity peptides were screened by quantitative structure-activity relationship (QSAR) modeling integrated with molecular docking analysis. Hydrolysates (<3 kDa) derived from combinations of thermolysin + alcalase and thermolysin + proteinase K demonstrated high ACE inhibitory activities. Peptide sequences in hydrolysates derived from these two combinations were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). On the basis of the QSAR modeling prediction, a total of 16 peptides were selected for molecular docking analysis. The docking study revealed that four of the peptides (KFPQY, MPFPKYP, MFPPQ, and QWQVL) bound the active site of ACE. These four novel peptides were chemically synthesized, and their IC 50 was determined. Among these peptides, KFPQY showed the highest ACE inhibitory activity (IC 50 = 12.37 ± 0.43 μM). Our study indicated that Qula casein presents an excellent source to produce ACE inhibitory peptides.

Characterization of angiotensin-I converting enzyme inhibiting peptide from Venerupis philippinarum with nano-liquid chromatography in combination with orbitrap mass spectrum detection and molecular docking

NASA Astrophysics Data System (ADS)

Shi, Lei; Wu, Tizhi; Sheng, Naijuan; Yang, Li; Wang, Qian; Liu, Rui; Wu, Hao

2017-06-01

The complexity and diversity of peptide mixture from protein hydrolysates make their characterization difficult. In this study, a method combining nano LC-MS/MS with molecular docking was applied to identifying and characterizing a peptide with angiotensin-I converting enzyme (ACE-I) inhibiting activity from Venerupis philippinarum hydrolysate. Firstly, ethanol supernatant of V. philippinarum hydrolysate was separated into active fractions with chromatographic methods such as ion-exchange chromatography and high performance liquid chromatography in combination. Then seven peptides from active fraction were identified according to the searching result of the MS/MS spectra against protein databases. Peptides were synthesized and subjected to ACE-I-inhibition assay. The peptide NTLTLIDTGIGMTK showed the highest potency with an IC50 of 5.75 μmol L-1. The molecular docking analysis showed that the ACE-I inhibiting peptide NTLTLIDTGIGMTK bond with residues Glu123, Glu403, Arg522, Glu376, Gln281 and Asn285 of ACE-I. Therefore, active peptides could be identified with the present method rather than the traditional purification and identification strategies. It may also be feasible to identify other food-derived peptides which target other enzymes and receptors with the method developed in this study.

Angiotensin Converting Enzyme Regulates Cell Proliferation and Migration

PubMed Central

Carvalho, Clarissa Coelho; Florentino, Rodrigo Machado; França, Andressa; Matias, Eveline; Guimarães, Paola Bianchi; Batista, Carolina; Freire, Valder; Carmona, Adriana Karaoglanovic; Pesquero, João Bosco; de Paula, Ana Maria; Foureaux, Giselle; Leite, Maria de Fatima

2016-01-01

Background The angiotensin-I converting enzyme (ACE) plays a central role in the renin-angiotensin system, acting by converting the hormone angiotensin-I to the active peptide angiotensin-II (Ang-II). More recently, ACE was shown to act as a receptor for Ang-II, and its expression level was demonstrated to be higher in melanoma cells compared to their normal counterparts. However, the function that ACE plays as an Ang-II receptor in melanoma cells has not been defined yet. Aim Therefore, our aim was to examine the role of ACE in tumor cell proliferation and migration. Results We found that upon binding to ACE, Ang-II internalizes with a faster onset compared to the binding of Ang-II to its classical AT1 receptor. We also found that the complex Ang-II/ACE translocates to the nucleus, through a clathrin-mediated process, triggering a transient nuclear Ca2+ signal. In silico studies revealed a possible interaction site between ACE and phospholipase C (PLC), and experimental results in CHO cells, demonstrated that the β3 isoform of PLC is the one involved in the Ca2+ signals induced by Ang-II/ACE interaction. Further studies in melanoma cells (TM-5) showed that Ang-II induced cell proliferation through ACE activation, an event that could be inhibited either by ACE inhibitor (Lisinopril) or by the silencing of ACE. In addition, we found that stimulation of ACE by Ang-II caused the melanoma cells to migrate, at least in part due to decreased vinculin expression, a focal adhesion structural protein. Conclusion ACE activation regulates melanoma cell proliferation and migration. PMID:27992423

Acute Bradykinin Receptor Blockade During Hemorrhagic Shock in Mice Prevents the Worsening Hypotensive Effect of Angiotensin-Converting Enzyme Inhibitor.

PubMed

Charbonneau, Hélène; Buléon, Marie; Minville, Vincent; Faguer, Stanislas; Girolami, Jean-Pierre; Bascands, Jean-Loup; Tack, Ivan; Mayeur, Nicolas

2016-09-01

Angiotensin-converting enzyme inhibitors are associated with deleterious hypotension during anesthesia and shock. Because the pharmacologic effects of angiotensin-converting enzyme inhibitors are partly mediated by increased bradykinin B2 receptor activation, this study aimed to determine the impact of acute B2 receptor blockade during hemorrhagic shock in angiotensin-converting enzyme inhibitor-treated mice. In vivo study. University research unit. C57/Bl6 mice. The hemodynamic effect of B2 receptor blockade using icatibant (B2 receptor antagonist) was studied using a pressure-targeted hemorrhagic shock and a volume-targeted hemorrhagic shock. Animals were anesthetized with ketamine and xylazine (250 mg/kg and 10 mg/kg, respectively), intubated using intratracheal cannula, and ventilated (9 mL/kg, 150 min). Five groups were studied: 1) sham-operated animals, 2) control shocked mice, 3) shocked mice treated with ramipril for 7 days (angiotensin-converting enzyme inhibitors) before hemorrhagic shock, 4) shocked mice treated with angiotensin-converting enzyme inhibitors and a single bolus of icatibant (HOE-140) immediately before anesthesia (angiotensin-converting enzyme inhibitors + icatibant), and 5) shocked mice treated with a single bolus of icatibant. One hour after volume-targeted hemorrhagic shock, blood lactate was measured to evaluate organ failure. During pressure-targeted hemorrhagic shock, the mean blood volume withdrawn was significantly lower in the angiotensin-converting enzyme inhibitor group than in the other groups (p < 0.001). During volume-targeted hemorrhagic shock, icatibant prevented blood pressure lowering in the angiotensin-converting enzyme inhibitor group (p < 0.001). Blood lactate was significantly higher in the angiotensin-converting enzyme inhibitor group than in the other groups, particularly the HOE groups. During hemorrhagic shock, acute B2 receptor blockade significantly attenuates the deleterious hemodynamic effect of angiotensin-converting

Aronia melanocarpa Elliot reduces the activity of angiotensin i-converting enzyme-in vitro and ex vivo studies.

PubMed

Sikora, Joanna; Broncel, Marlena; Mikiciuk-Olasik, Elżbieta

2014-01-01

The aim of the study was to analyze the effects of two-month supplementation with chokeberry preparation on the activity of angiotensin I-converting enzyme (ACE) in patients with metabolic syndrome (MS). During the in vitro stage of the study, we determined the concentration of chokeberry extract, which inhibited the activity of ACE by 50% (IC50). The participants (n = 70) were divided into three groups: I-patients with MS who received chokeberry extract supplements, II-healthy controls, and III-patients with MS treated with ACE inhibitors. After one and two months of the experiment, a decrease in ACE activity corresponded to 25% and 30%, respectively. We documented significant positive correlations between the ACE activity and the systolic (r = 0.459, P = 0.048) and diastolic blood pressure, (r = 0.603, P = 0.005) and CRP. The IC50 of chokeberry extract and captopril amounted to 155.4 ± 12.1 μg/mL and 0.52 ± 0.18 μg/mL, respectively. Our in vitro study revealed that chokeberry extract is a relatively weak ACE inhibitor. However, the results of clinical observations suggest that the favorable hypotensive action of chokeberry polyphenols may be an outcome of both ACE inhibition and other pleotropic effects, for example, antioxidative effect.

Impact of I/D polymorphism of angiotensin-converting enzyme (ACE) gene on myocardial infarction susceptibility among young Moroccan patients.

PubMed

Hmimech, Wiam; Idrissi, Hind Hassani; Diakite, Brehima; Korchi, Farah; Baghdadi, Dalila; Tahri Joutey Hassani Idrissi, Hind; Haboub, Meriem; Habbal, Rachida; Nadifi, Sellama

2017-12-21

Our case-control study aimed to access the potential association of insertion/deletion (I/D) ACE (angiotensin converting enzyme) gene polymorphism with myocardial infarction (MI) risk of occurrence among a sample of Moroccan patients, especially young ones. Distribution of I/D ACE gene variant among cases vs controls, showed that healthy controls carried out higher frequency of wild type allele I compared to cases (23.5% vs 21.79% respectively), when cases were carrying higher frequency of mutant allele D (78.21% vs 76.5% for controls). Patients were-after this- divided into two groups of < 45 and > 55 years of age, to investigate whether or not younger patients carried out higher frequency of the mutant allele D, than older ones. As expected, < 45 years old patients carried out more DD genotype than older ones (68.9% vs 54.6% respectively), and higher frequency of mutant allele D (81.08% vs 75% respectively). Besides, a tendency to a positive association was found under the recessive genetic transmission model (OR [95% CI] = 1.85 [0.93-3.69], P = 0.08), suggesting that the I/D ACE polymorphism may be associated with MI occurrence among younger patients (< 45 years of age).

Serum angiotensin-1 converting enzyme activity processes a human immunodeficiency virus 1 gp160 peptide for presentation by major histocompatibility complex class I molecules

PubMed Central

1992-01-01

T cell stimulation by the human immunodeficiency virus 1 gp160-derived peptide p18 presented by H-2Dd class I major histocompatibility complex molecules in a cell-free system was found to require proteolytic cleavage. This extracellular processing was mediated by peptidases present in fetal calf serum. In vitro processing of p18 resulted in a distinct reverse phase high performance liquid chromatography profile, from which a biologically active product was isolated and sequenced. This peptide processing can be specifically blocked by the angiotensin- 1 converting enzyme (ACE) inhibitor captopril, and can occur by exposing p18 to purified ACE. The ability of naturally occurring extracellular proteases to convert inactive peptides to T cell antigens has important implications for understanding cytotoxic T lymphocyte responses in vivo, and for rational peptide vaccine design. PMID:1316930

Gene structure and mutations of glutaryl-coenzyme A dehydrogenase: Impaired association of enzyme subunits that is due to an A421V substitution causes glutaric acidemia type I in the Amish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biery, B.J.; Stein, D.E.; Goodman, S.I.

The structure of the human glutaryl coenzyme A dehydrogenase (GCD) gene was determined to contain 11 exons and to span {approximately}7 kb. Fibroblast DNA from 64 unrelated glutaric academia type I (GA1) patients was screened for mutations by PCR amplification and analysis of SSCP. Fragments with altered electrophoretic mobility were subcloned and sequenced to detect mutations that caused GA1. This report describes the structure of the GCD gene, as well as point mutations and polymorphisms found in 7 of its 11 exons. Several mutations were found in more than one patient, but no one prevalent mutation was detected in themore » general population. As expected from pedigree analysis, a single mutant allele causes GA1 in the Old Order Amish of Lancaster County, Pennsylvania. Several mutations have been expressed in Escherichia coli, and all produce diminished enzyme activity. Reduced activity in GCD encoded by the A421V mutation in the Amish may be due to impaired association of enzyme subunits. 13 refs., 5 figs., 3 tabs.« less

STRUCTURAL CHARACTERISTICS AND ANTIHYPERTENSIVE EFFECTS OF ANGIOTENSIN-I-CONVERTING ENZYME INHIBITORY PEPTIDES IN THE RENIN-ANGIOTENSIN AND KALLIKREIN KININ SYSTEMS

PubMed Central

Manoharan, Sivananthan; Shuib, Adawiyah Suriza; Abdullah, Noorlidah

2017-01-01

Background: The commercially available synthetic angiotensin-I-converting enzyme (ACE) inhibitors are known to exert negative side effects which have driven many research groups globally to discover the novel ACE inhibitors. Method: Literature search was performed within the PubMed, ScienceDirect.com and Google Scholar. Results: The presence of proline at the C-terminal tripeptide of ACE inhibitor can competitively inhibit the ACE activity. The effects of other amino acids are less studied leading to difficulties in predicting potent peptide sequences. The broad specificity of the enzyme may be due to the dual active sites observed on the somatic ACE. The inhibitors may not necessarily competitively inhibit the enzyme which explains why some reported inhibitors do not have the common ACE inhibitor characteristics. Finally, the in vivo assay has to be carried out before the peptides as the antihypertensive agents can be claimed. The peptides must be absorbed into circulation without being degraded, which will affect their bioavailability and potency. Thus, peptides with strong in vitro IC50 values do not necessarily have the same effect in vivo and vice versa. Conclusion: The relationship between peptide amino acid sequence and inhibitory activity, in vivo studies of the active peptides and bioavailability must be studied before the peptides as antihypertensive agents can be claimed. PMID:28573254

Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats.

PubMed

Ngo, Dai-Hung; Kang, Kyong-Hwa; Ryu, BoMi; Vo, Thanh-Sang; Jung, Won-Kyo; Byun, Hee-Guk; Kim, Se-Kwon

2015-05-01

The aim of this study was to investigate antihypertensive effect of bioactive peptides from skate (Okamejei kenojei) skin gelatin. The Alcalase/protease gelatin hydrolysate below 1 kDa (SAP) exhibited the highest angiotensin-I converting enzyme (ACE) inhibition compared to other hydrolysates. SAP can decrease systolic blood pressure significantly in spontaneously hypertensive rats. SAP inhibited vasoconstriction via PPAR-γ expression, activation and phosphorylation of eNOS in lungs. Moreover, the expression levels of endothelin-1, RhoA, α-smooth muscle actin, cleaved caspase 3 and MAPK were decreased by SAP in lungs. Vascularity, muscularization and cellular proliferation in lungs were detected by immunohistochemical staining. Finally, two purified peptides (LGPLGHQ, 720Da and MVGSAPGVL, 829Da) showed potent ACE inhibition with IC50 values of 4.22 and 3.09 μM, respectively. These results indicate that bioactive peptides isolated from skate skin gelatin may serve as candidates against hypertension and could be used as functional food ingredients. Copyright © 2014 Elsevier Ltd. All rights reserved.

The evolution of renin-angiotensin blockade: angiotensin-converting enzyme inhibitors as the starting point.

PubMed

Sica, Domenic A

2010-04-01

The renin-angiotensin system has been a target in the treatment of hypertension for close to three decades. Several medication classes that block specific aspects of this system have emerged as useful therapies, including angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and, most recently, direct renin inhibitors. There has been a natural history to the development of each of these three drug classes, starting with their use as antihypertensive agents; thereafter, in each case they have been employed as end-organ protective agents. To date, there has been scant evidence to favor angiotensin receptor blockers or direct renin inhibitors over angiotensin-converting enzyme inhibitors in treating hypertension or in affording end-organ protection; thus, angiotensin-converting enzyme inhibitors remain the standard of care when renin-angiotensin system blockade is warranted.

Preparation and characterization of novel bioactive peptides responsible for angiotensin I-converting enzyme inhibition from wheat germ.

PubMed

Matsui, T; Li, C H; Osajima, Y

1999-07-01

Reported is the preparation of wheat germ (WG) hydrolyzate with potent angiotensin I-converting enzyme (ACE) inhibitory activity, and the characterization of peptides responsible for ACE inhibition. Successful hydrolyzate with the most potent ACE inhibitory activity was obtained by 0.5 wt.%-8 h Bacillus licheniformis alkaline protease hydrolysis after 3.0 wt.%-3 h alpha-amylase treatment of defatted WG (IC50; 0.37 mg protein ml(-1)). The activity of WG hydrolyzate was markedly increased by ODS and subsequent AG50W purifications (IC50; 0.018 mg protein ml(-1)). As a result of isolations by high performance liquid chromatographies, 16 peptides with the IC50 value of less than 20 microM, composed of 2-7 amino acid residues were identified from the WG hydrolyzate. Judging from the high content (260 mg in 100 g of AG50W fraction) and powerful ACE inhibitory activity (IC50; 0.48 microM), Ile-Val-Tyr was identified as a main contributor to the ACE inhibition of the hydrolyzate.

Effect of NaeI-L43K mutation on protein dynamics and DNA conformation: Insights from molecular dynamics simulations.

PubMed

Ramachandrakurup, Sreelakshmi; Ramakrishnan, Vigneshwar

2017-09-01

Protein-DNA interactions are an important class of biomolecular interactions inside the cell. Delineating the mechanisms of protein-DNA interactions and more specifically, how proteins search and bind to their specific cognate sequences has been the quest of many in the scientific community. Restriction enzymes have served as useful model systems to this end. In this work, we have investigated using molecular dynamics simulations the effect of L43K mutation on NaeI, a type IIE restriction enzyme. NaeI has two domains, the Topo and the Endo domains, each binding to identical strands of DNA sequences (GCCGGC) 2 . The binding of the DNA to the Topo domain is thought to enhance the binding and cleavage of DNA at the Endo domain. Interestingly, it has been found that the mutation of an amino acid that is distantly-located from the DNA cleavage site (L43K) converts the restriction endonuclease to a topoisomerase. Our investigations reveal that the L43K mutation not only induces local structural changes (as evidenced by changes in hydrogen bond propensities and differences in the percentage of secondary structure assignments of the residues in the ligase-like domain) but also alters the overall protein dynamics and DNA conformation which probably leads to the loss of specific cleavage of the recognition site. In a larger context, our study underscores the importance of considering the role of distantly-located amino acids in understanding protein-DNA interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

Angiotensin I-Converting Enzyme Inhibitor Derived from Cross-Linked Oyster Protein

PubMed Central

Xie, Cheng-Liang; Kim, Jin-Soo; Ha, Jong-Myung; Choung, Se-Young

2014-01-01

Following cross-linking by microbial transglutaminase, modified oyster proteins were hydrolyzed to improve inhibitory activity against angiotensin-converting enzyme (ACE) inhibitory activity with the use of a single protease, or a combination of six proteases. The oyster hydrolysate with the lowest 50% ACE inhibitory concentration (IC50) of 0.40 mg/mL was obtained by two-step hydrolysis of the cross-linked oyster protein using Protamex and Neutrase. Five ACE inhibitory peptides were purified from the oyster hydrolysate using a multistep chromatographic procedure comprised of ion-exchange, size exclusion, and reversed-phase liquid chromatography. Their sequences were identified as TAY, VK, KY, FYN, and YA, using automated Edman degradation and mass spectrometry. These peptides were synthesized, and their IC50 values were measured to be 16.7, 29.0, 51.5, 68.2, and 93.9 μM, respectively. Toxicity of the peptides on the HepG2 cell line was not detected. The oyster hydrolysate also significantly decreased the systolic blood pressure of spontaneously hypertensive rats (SHR). The antihypertensive effect of the oyster hydrolysate on SHR was rapid and long-lasting, compared to commercially obtained sardine hydrolysate. These results suggest that the oyster hydrolysate could be a source of effective nutraceuticals against hypertension. PMID:25140307

Effect of Jatropha curcas Peptide Fractions on the Angiotensin I-Converting Enzyme Inhibitory Activity

PubMed Central

Segura-Campos, Maira R.; Peralta-González, Fanny; Castellanos-Ruelas, Arturo; Chel-Guerrero, Luis A.; Betancur-Ancona, David A.

2013-01-01

Hypertension is one of the most common worldwide diseases in humans. Angiotensin I-converting enzyme (ACE) plays an important role in regulating blood pressure and hypertension. An evaluation was done on the effect of Alcalase hydrolysis of defatted Jatropha curcas kernel meal on ACE inhibitory activity in the resulting hydrolysate and its purified fractions. Alcalase exhibited broad specificity and produced a protein hydrolysate with a 21.35% degree of hydrolysis and 34.87% ACE inhibition. Ultrafiltration of the hydrolysate produced peptide fractions with increased biological activity (24.46–61.41%). Hydrophobic residues contributed substantially to the peptides' inhibitory potency. The 5–10 and <1 kDa fractions were selected for further fractionation by gel filtration chromatography. ACE inhibitory activity (%) ranged from 22.66 to 45.96% with the 5–10 kDa ultrafiltered fraction and from 36.91 to 55.83% with the <1 kDa ultrafiltered fraction. The highest ACE inhibitory activity was observed in F2 (IC50 = 6.7 μg/mL) from the 5–10 kDa fraction and F1 (IC50 = 4.78 μg/mL) from the <1 kDa fraction. ACE inhibitory fractions from Jatropha kernel have potential applications in alternative hypertension therapies, adding a new application for the Jatropha plant protein fraction and improving the financial viability and sustainability of a Jatropha-based biodiesel industry. PMID:24224169

Analysis of serum angiotensin-converting enzyme.

PubMed

Muller, B R

2002-09-01

Serum angiotensin-converting enzyme (SACE) levels are influenced by genetic polymorphism. Interpretation of serum levels with the appropriate genotypic reference range improves the diagnostic sensitivity of the assay for sarcoidosis. SACE assays are performed by a large number of routine clinical laboratories. However, there is no external quality assessment (EQA) for SACE other than an informal regional scheme. This showed analytical performance of SACE assays to be poor, with a diversity of reference ranges, leading to widely disparate clinical classification of EQA samples. Genetic polymorphism combined with poor analytical performance suggest that perhaps SACE assays should revert to being the province of specialized laboratories.

Substance P increases Sympathetic Activity during Combined Angiotensin Converting Enzyme and Dipeptidyl Peptidase-4 Inhibition

PubMed Central

Devin, Jessica K.; Pretorius, Mias; Nian, Hui; Yu, Chang; Billings, Frederic T.; Brown, Nancy J.

2014-01-01

Dipeptidyl peptidase-4 inhibitors prevent the degradation of incretin hormones and reduce post-prandial hyperglycemia in patients with type 2 diabetes mellitus. Dipeptidyl peptidase-4 degrades other peptides with a penultimate proline or alanine, including bradykinin and substance P, which are also substrates of angiotensin-converting enzyme. During angiotensin-converting enzyme inhibition, substance P is inactivated primarily by dipeptidyl peptidase-4, while bradykinin is first inactivated by aminopeptidase P. This study tested the hypothesis that dipeptidyl peptidase-4 inhibition potentiates vasodilator and fibrinolytic responses to substance P when angiotensin-converting enzyme is inhibited. Twelve healthy subjects participated in this randomized, double-blinded, placebo-controlled crossover study. On each study day, subjects received sitagliptin 200 mg p.o. or placebo. Substance P and bradykinin were infused via brachial artery before and during intra-arterial enalaprilat. Sitagliptin and enalaprilat each reduced forearm vascular resistance and increased forearm blood flow without affecting mean arterial pressure, but there was no interactive effect of the inhibitors. Enalaprilat increased bradykinin-stimulated vasodilation and tissue plasminogen activator release; sitagliptin did not affect these responses to bradykinin. The vasodilator response to substance P was unaffected by sitagliptin and enalaprilat, however, substance P increased heart rate and vascular release of norepinephrine during combined angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibition. In women, sitagliptin diminished tissue plasminogen activator release in response to substance P both alone and during enalaprilat. Substance P increases sympathetic activity during combined angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibition. PMID:24516103

Mutation of the myosin converter domain alters cross-bridge elasticity

PubMed Central

Köhler, Jan; Winkler, Gerhard; Schulte, Imke; Scholz, Tim; McKenna, William; Brenner, Bernhard; Kraft, Theresia

2002-01-01

Elastic distortion of a structural element of the actomyosin complex is fundamental to the ability of myosin to generate motile forces. An elastic element allows strain to develop within the actomyosin complex (cross-bridge) before movement. Relief of this strain then drives filament sliding, or more generally, movement of a cargo. Even with the known crystal structure of the myosin head, however, the structural element of the actomyosin complex in which elastic distortion occurs remained unclear. To assign functional relevance to various structural elements of the myosin head, e.g., to identify the elastic element within the cross-bridge, we studied mechanical properties of muscle fibers from patients with familial hypertrophic cardiomyopathy with point mutations in the head domain of the β-myosin heavy chain. We found that the Arg-719 → Trp (Arg719Trp) mutation, which is located in the converter domain of the myosin head fragment, causes an increase in force generation and fiber stiffness under isometric conditions by 48–59%. Under rigor and relaxing conditions, fiber stiffness was 45–47% higher than in control fibers. Yet, kinetics of active cross-bridge cycling were unchanged. These findings, especially the increase in fiber stiffness under rigor conditions, indicate that cross-bridges with the Arg719Trp mutation are more resistant to elastic distortion. The data presented here strongly suggest that the converter domain that forms the junction between the catalytic and the light-chain-binding domain of the myosin head is not only essential for elastic distortion of the cross-bridge, but that the main elastic distortion may even occur within the converter domain itself. PMID:11904418

Angiotensin converting enzyme inhibitors and aortic arch obstructive malformations.

PubMed

Maliheh, Kadivar; Abdorrazagh, Kiani; Armen, Kocharian; Reza, Shabanian

2006-10-01

We describe two newborn infants with aortic arch obstructive malformations who became anuric after initiation of captopril. Since angiotensin converting enzyme inhibitors can alter renal blood flow by reduction in angiotensin II and blocking autoregulation phenomenon, it is important to use them with great caution in neonates with aortic arch obstructive malformations, while monitoring their renal function closely.

Trade-offs between enzyme fitness and solubility illuminated by deep mutational scanning

PubMed Central

Bacik, John-Paul; Wrenbeck, Emily E.; Michalczyk, Ryszard; Whitehead, Timothy A.

2017-01-01

Proteins are marginally stable, and an understanding of the sequence determinants for improved protein solubility is highly desired. For enzymes, it is well known that many mutations that increase protein solubility decrease catalytic activity. These competing effects frustrate efforts to design and engineer stable, active enzymes without laborious high-throughput activity screens. To address the trade-off between enzyme solubility and activity, we performed deep mutational scanning using two different screens/selections that purport to gauge protein solubility for two full-length enzymes. We assayed a TEM-1 beta-lactamase variant and levoglucosan kinase (LGK) using yeast surface display (YSD) screening and a twin-arginine translocation pathway selection. We then compared these scans with published experimental fitness landscapes. Results from the YSD screen could explain 37% of the variance in the fitness landscapes for one enzyme. Five percent to 10% of all single missense mutations improve solubility, matching theoretical predictions of global protein stability. For a given solubility-enhancing mutation, the probability that it would retain wild-type fitness was correlated with evolutionary conservation and distance to active site, and anticorrelated with contact number. Hybrid classification models were developed that could predict solubility-enhancing mutations that maintain wild-type fitness with an accuracy of 90%. The downside of using such classification models is the removal of rare mutations that improve both fitness and solubility. To reveal the biophysical basis of enhanced protein solubility and function, we determined the crystallographic structure of one such LGK mutant. Beyond fundamental insights into trade-offs between stability and activity, these results have potential biotechnological applications. PMID:28196882

Demonstration of extrapulmonary activity of angiotensin converting enzyme in intact tissue preparations.

PubMed

Lembeck, F; Griesbacher, T; Eckhardt, M

1990-05-01

1. The activity of angiotensin converting enzyme (ACE) has been studied on functional parameters of intact isolated preparations of extrapulmonary tissues. The conversion of angiotensin I (A I) to angiotensin II (A II) and the cleavage of bradykinin (BK) were used as indicators of ACE activity. Captopril was employed as a specific inhibitor of ACE. 2. Captopril augmented the BK-induced contractions of the rat isolated uterus, the BK- and substance P-induced contractions of the guinea-pig ileum, and the BK-induced venoconstriction in the isolated perfused ear of the rabbit. Degradation of BK by ACE was calculated to be 52% in the rat uterus and 75% in the rabbit perfused ear. 3. Captopril inhibited the A I-induced contractions of the rat isolated colon, the A I-induced vasoconstriction in the isolated perfused ear of the rabbit and the rise in blood pressure induced by i.a. injections of A I in pithed rats. Conversion of A I to A II was calculated to be 13% in the rat colon and 26% in the rabbit perfused ear. 4. From estimations of the A II activity (bioassay on the rat colon) in the effluent of the perfused ear of the rabbit after injections of A I into the arterial inflow cannula it was calculated that approximately one tenth of A I was converted to A II during a single passage through the ear (less than 15 s). 5. The present experiments suggest that the high activity of ACE in endothelium of blood vessels of extrapulmonary tissues may provide an additional (endothelium-dependent) local vasoconstrictor mechanism by the rapid formation of A II and inactivation of BK. The ACE activity in non-vascular smooth muscles, other than those of blood vessels, may also affect the physiological functions of these tissues.

Novel angiotensin I-converting enzyme inhibitory peptides produced in fermented milk by specific wild Lactococcus lactis strains.

PubMed

Rodríguez-Figueroa, J C; González-Córdova, A F; Torres-Llanez, M J; Garcia, H S; Vallejo-Cordoba, B

2012-10-01

The ability of specific wild Lactococcus lactis strains to hydrolyze milk proteins to release angiotensin I-converting enzyme (ACE) inhibitory peptides was evaluated. The peptide profiles were obtained from the <3 kDa water-soluble extract and subsequently fractionated by reversed-phase HPLC. The fractions with the lowest half-maximal inhibitory concentration estimated values (peptide concentration necessary to inhibit ACE activity by 50%) were Lc. lactis NRRL B-50571 fraction (F)1 (0.034 ± 0.002 μg/mL; mean ± SD) and Lc. lactis NRRL B-50572B F 0005 (0.041 ± 0.003 μg/mL; mean ± SD). All peptide fractions were analyzed by reversed-phase HPLC tandem mass spectrometry. Twenty-one novel peptide sequences associated with ACE inhibitory (ACEI) activity were identified. Several novel ACEI peptides presented peptides encrypted with proven hypotensive activity. In conclusion, specific wild Lc. lactis strains were able to hydrolyze milk proteins to generate potent ACEI peptides. However, further studies are necessary to find out the relationship between Lc. lactis strain proteolytic systems and their ability to biogenerate hypotensive peptides. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

New Perspectives in the Renin-Angiotensin-Aldosterone System (RAAS) I: Endogenous Angiotensin Converting Enzyme (ACE) Inhibition

PubMed Central

Fagyas, Miklós; Úri, Katalin; Siket, Ivetta M.; Daragó, Andrea; Boczán, Judit; Bányai, Emese; Édes, István; Papp, Zoltán; Tóth, Attila

2014-01-01

Angiotensin-converting enzyme (ACE) inhibitors represent the fifth most often prescribed drugs. ACE inhibitors decrease 5-year mortality by approximately one-fifth in cardiovascular patients. Surprisingly, there are reports dating back to 1979 suggesting the existence of endogenous ACE inhibitors, which endogenous inhibitory effects are much less characterized than that for the clinically administered ACE inhibitors. Here we aimed to investigate this endogenous ACE inhibition in human sera. It was hypothesized that ACE activity is masked by an endogenous inhibitor, which dissociates from the ACE when its concentration decreases upon dilution. ACE activity was measured by FAPGG hydrolysis first. The specific (dilution corrected) enzyme activities significantly increased by dilution of human serum samples (23.2±0.7 U/L at 4-fold dilution, 51.4±0.3 U/L at 32-fold dilution, n = 3, p = 0.001), suggesting the presence of an endogenous inhibitor. In accordance, specific enzyme activities did not changed by dilution when purified renal ACE was used, where no endogenous inhibitor was present (655±145 U/L, 605±42 U/L, n = 3, p = 0.715, respectively). FAPGG conversion strongly correlated with angiotensin I conversion suggesting that this feature is not related to the artificial substrate. Serum samples were ultra-filtered to separate ACE (MW: 180 kDa) and the hypothesized inhibitor. Filtering through 50 kDa filters was without effect, while filtering through 100 kDa filters eliminated the inhibiting factor (ACE activity after <100 kDa filtering: 56.4±2.4 U/L, n = 4, control: 26.4±0.7 U/L, n = 4, p<0.001). Lineweaver-Burk plot indicated non-competitive inhibition of ACE by this endogenous factor. The endogenous inhibitor had higher potency on the C-terminal active site than N-terminal active site of ACE. Finally, this endogenous ACE inhibition was also present in mouse, donkey, goat, bovine sera besides men (increasing of specific ACE activity

Crystal structure of the N domain of human somatic angiotensin I-converting enzyme provides a structural basis for domain-specific inhibitor design.

PubMed

Corradi, Hazel R; Schwager, Sylva L U; Nchinda, Aloysius T; Sturrock, Edward D; Acharya, K Ravi

2006-03-31

Human somatic angiotensin I-converting enzyme (sACE) is a key regulator of blood pressure and an important drug target for combating cardiovascular and renal disease. sACE comprises two homologous metallopeptidase domains, N and C, joined by an inter-domain linker. Both domains are capable of cleaving the two hemoregulatory peptides angiotensin I and bradykinin, but differ in their affinities for a range of other substrates and inhibitors. Previously we determined the structure of testis ACE (C domain); here we present the crystal structure of the N domain of sACE (both in the presence and absence of the antihypertensive drug lisinopril) in order to aid the understanding of how these two domains differ in specificity and function. In addition, the structure of most of the inter-domain linker allows us to propose relative domain positions for sACE that may contribute to the domain cooperativity. The structure now provides a platform for the design of "domain-specific" second-generation ACE inhibitors.

Angiotensin-converting enzyme in epithelial and neuroepithelial cells.

PubMed

Defendini, R; Zimmerman, E A; Weare, J A; Alhenc-Gelas, F; Erdös, E G

1983-07-01

Angiotensin-converting enzyme (CE) occurs in three types of cell: endothelial, epithelial, and neuroepithelial. In all three, it appears to be bound to plasma membrane. With antisera to the human enzyme, CE is demonstrated in paraffin sections on the apical surface of epithelial cells in the proximal tubule of the kidney, the mucosa of the small intestine, the syncytial trophoblast of the placenta, and the choroid plexus. Epithelial CE is characteristically found on microvillous surfaces in contact with an effluent, well placed to act on substrate in flux. In the brain, CE occurs in nerve fibers and terminals, mainly mesiobasally and in basal ganglia. Mesiobasal CE coincides with other components of the renin-angiotensin system (RAS) in the choroid/ventricular fluid, the subfornical organ, and the magnocellular neurosecretory system of the hypothalamus. Extrapyramidal CE, however, may not be related to the RAS. In the substantia nigra and the globus pallidus, the enzyme has the same cellular distribution as two putative neuromodulators, substance P and enkephalin, the latter a known substrate of CE.

Primacy of cardiac chymase over angiotensin converting enzyme as an angiotensin-(1-12) metabolizing enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Sarfaraz; Varagic, Jasmina; Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC

We showed previously that rat angiotensin-(1-12) [Ang-(1-12)] is metabolized by chymase and angiotensin converting enzyme (ACE) to generate Angiotensin II (Ang II). Here, we investigated the affinity of cardiac chymase and ACE enzymes for Ang-(1-12) and Angiotensin I (Ang I) substrates. Native plasma membranes (PMs) isolated from heart and lung tissues of adult spontaneously hypertensive rats (SHR) were incubated with radiolabeled {sup 125}I-Ang-(1-12) or {sup 125}I-Ang I, in the absence or presence of a chymase or ACE inhibitor (chymostatin and lisinopril, respectively). Products were quantitated by HPLC connected to an in-line flow-through gamma detector. The rate of {sup 125}I-Ang IImore » formation from {sup 125}I-Ang-(1-12) by chymase was significantly higher (heart: 7.0 ± 0.6 fmol/min/mg; lung: 33 ± 1.2 fmol/min/mg, P < 0.001) when compared to {sup 125}I-Ang I substrate (heart: 0.8 ± 0.1 fmol/min/mg; lung: 2.1 ± 0.1 fmol/min/mg). Substrate affinity of {sup 125}I-Ang-(1-12) for rat cardiac chymase was also confirmed using excess unlabeled Ang-(1-12) or Ang I (0–250 μM). The rate of {sup 125}I-Ang II formation was significantly lower using unlabeled Ang-(1-12) compared to unlabeled Ang I substrate. Kinetic data showed that rat chymase has a lower K{sub m} (64 ± 6.3 μM vs 142 ± 17 μM), higher V{sub max} (13.2 ± 1.3 μM/min/mg vs 1.9 ± 0.2 μM/min/mg) and more than 15-fold higher catalytic efficiency (ratio of V{sub max}/K{sub m}) for Ang-(1-12) compared to Ang I substrate, respectively. We also investigated ACE mediated hydrolysis of {sup 125}I-Ang-(1-12) and {sup 125}I-Ang I in solubilized membrane fractions of the SHR heart and lung. Interestingly, no significant difference in {sup 125}I-Ang II formation by ACE was detected using either substrate, {sup 125}I-Ang-(1-12) or {sup 125}I-Ang I, both in the heart (1.8 ± 0.2 fmol/min/mg and 1.8 ± 0.3 fmol/min/mg, respectively) and in the lungs (239 ± 25�

Prosegment of tripeptidyl peptidase I is a potent, slow-binding inhibitor of its cognate enzyme.

PubMed

Golabek, Adam A; Dolzhanskaya, Natalia; Walus, Marius; Wisniewski, Krystyna E; Kida, Elizabeth

2008-06-13

Tripeptidyl peptidase I (TPP I) is the first mammalian representative of a family of pepstatin-insensitive serine-carboxyl proteases, or sedolisins. The enzyme acts in lysosomes, where it sequentially removes tripeptides from the unmodified N terminus of small, unstructured polypeptides. Naturally occurring mutations in TPP I underlie a neurodegenerative disorder of childhood, classic late infantile neuronal ceroid lipofuscinosis (CLN2). Generation of mature TPP I is associated with removal of a long prosegment of 176 amino acid residues from the zymogen. Here we investigated the inhibitory properties of TPP I prosegment expressed and isolated from Escherichia coli toward its cognate protease. We show that the TPP I prosegment is a potent, slow-binding inhibitor of its parent enzyme, with an overall inhibition constant in the low nanomolar range. We also demonstrate the protective effect of the prosegment on alkaline pH-induced inactivation of the enzyme. Interestingly, the inhibitory properties of TPP I prosegment with the introduced classic late infantile neuronal ceroid lipofuscinosis disease-associated mutation, G77R, significantly differed from those revealed by wild-type prosegment in both the mechanism of interaction and the inhibitory rate. This is the first characterization of the inhibitory action of the sedolisin prosegment.

Prosegment of Tripeptidyl Peptidase I Is a Potent, Slow-binding Inhibitor of Its Cognate Enzyme*

PubMed Central

Golabek, Adam A.; Dolzhanskaya, Natalia; Walus, Marius; Wisniewski, Krystyna E.; Kida, Elizabeth

2008-01-01

Tripeptidyl peptidase I (TPP I) is the first mammalian representative of a family of pepstatin-insensitive serine-carboxyl proteases, or sedolisins. The enzyme acts in lysosomes, where it sequentially removes tripeptides from the unmodified N terminus of small, unstructured polypeptides. Naturally occurring mutations in TPP I underlie a neurodegenerative disorder of childhood, classic late infantile neuronal ceroid lipofuscinosis (CLN2). Generation of mature TPP I is associated with removal of a long prosegment of 176 amino acid residues from the zymogen. Here we investigated the inhibitory properties of TPP I prosegment expressed and isolated from Escherichia coli toward its cognate protease. We show that the TPP I prosegment is a potent, slow-binding inhibitor of its parent enzyme, with an overall inhibition constant in the low nanomolar range. We also demonstrate the protective effect of the prosegment on alkaline pH-induced inactivation of the enzyme. Interestingly, the inhibitory properties of TPP I prosegment with the introduced classic late infantile neuronal ceroid lipofuscinosis disease-associated mutation, G77R, significantly differed from those revealed by wild-type prosegment in both the mechanism of interaction and the inhibitory rate. This is the first characterization of the inhibitory action of the sedolisin prosegment. PMID:18411270

Mutations in the SPTLC2 Subunit of Serine Palmitoyltransferase Cause Hereditary Sensory and Autonomic Neuropathy Type I

PubMed Central

Rotthier, Annelies; Auer-Grumbach, Michaela; Janssens, Katrien; Baets, Jonathan; Penno, Anke; Almeida-Souza, Leonardo; Van Hoof, Kim; Jacobs, An; De Vriendt, Els; Schlotter-Weigel, Beate; Löscher, Wolfgang; Vondráček, Petr; Seeman, Pavel; De Jonghe, Peter; Van Dijck, Patrick; Jordanova, Albena; Hornemann, Thorsten; Timmerman, Vincent

2010-01-01

Hereditary sensory and autonomic neuropathy type I (HSAN-I) is an axonal peripheral neuropathy associated with progressive distal sensory loss and severe ulcerations. Mutations in the first subunit of the enzyme serine palmitoyltransferase (SPT) have been associated with HSAN-I. The SPT enzyme catalyzes the first and rate-limiting step in the de novo sphingolipid synthesis pathway. However, different studies suggest the implication of other genes in the pathology of HSAN-I. Therefore, we screened the two other known subunits of SPT, SPTLC2 and SPTLC3, in a cohort of 78 HSAN patients. No mutations were found in SPTLC3, but we identified three heterozygous missense mutations in the SPTLC2 subunit of SPT in four families presenting with a typical HSAN-I phenotype. We demonstrate that these mutations result in a partial to complete loss of SPT activity in vitro and in vivo. Moreover, they cause the accumulation of the atypical and neurotoxic sphingoid metabolite 1-deoxy-sphinganine. Our findings extend the genetic heterogeneity in HSAN-I and enlarge the group of HSAN neuropathies associated with SPT defects. We further show that HSAN-I is consistently associated with an increased formation of the neurotoxic 1-deoxysphinganine, suggesting a common pathomechanism for HSAN-I. PMID:20920666

A Modern Understanding of the Traditional and Nontraditional Biological Functions of Angiotensin-Converting Enzyme

PubMed Central

Ong, Frank S.; Blackwell, Wendell-Lamar B.; Shah, Kandarp H.; Giani, Jorge F.; Gonzalez-Villalobos, Romer A.; Shen, Xiao Z.; Fuchs, Sebastien

2013-01-01

Angiotensin-converting enzyme (ACE) is a zinc-dependent peptidase responsible for converting angiotensin I into the vasoconstrictor angiotensin II. However, ACE is a relatively nonspecific peptidase that is capable of cleaving a wide range of substrates. Because of this, ACE and its peptide substrates and products affect many physiologic processes, including blood pressure control, hematopoiesis, reproduction, renal development, renal function, and the immune response. The defining feature of ACE is that it is composed of two homologous and independently catalytic domains, the result of an ancient gene duplication, and ACE-like genes are widely distributed in nature. The two ACE catalytic domains contribute to the wide substrate diversity of ACE and, by extension, the physiologic impact of the enzyme. Several studies suggest that the two catalytic domains have different biologic functions. Recently, the X-ray crystal structure of ACE has elucidated some of the structural differences between the two ACE domains. This is important now that ACE domain-specific inhibitors have been synthesized and characterized. Once widely available, these reagents will undoubtedly be powerful tools for probing the physiologic actions of each ACE domain. In turn, this knowledge should allow clinicians to envision new therapies for diseases not currently treated with ACE inhibitors. PMID:23257181

Identification of new polymorphisms of the angiotensin I-converting enzyme (ACE) gene, and study of their relationship to plasma ACE levels by two-QTL segregation-linkage analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villard, E.; Soubrier, F.; Tiret, L.

1996-06-01

Plasma angiotensin I-converting enzyme (ACE) levels are highly genetically determined. A previous segregation-linkage analysis suggested the existence of a functional mutation located within or close to the ACE locus, in almost complete linkage disequilibrium (LD) with the ACE insertion/deletion (I/D) polymorphism and accounting for half the ACE variance. In order to identify the functional variant at the molecular level, we compared ACE gene sequences between four subjects selected for having contrasted ACE levels and I/D genotypes. We identified 10 new polymorphisms, among which 8 were genotyped in 95 healthy nuclear families, in addition to the I/D polymorphism. These polymorphisms couldmore » be divided into two groups: five polymorphisms in the 5{prime} region and three in the coding sequence and the 3{prime} UTR. Within each group, polymorphisms were in nearly complete association, whereas polymorphisms from the two groups were in strong negative LD. After adjustment for the I/D polymorphism, all polymorphisms of the 5{prime} group remained significantly associated with ACE levels, which suggests the existence of two quantitative trait loci (QTL) acting additively on ACE levels. Segregation-linkage analyses including one or two ACE-linked QTLs in LD with two ACE markers were performed to test this hypothesis. The two QTLs and the two markers were assumed to be in complete LD. Results supported the existence of two ACE-linked QTLs, which would explain 38% and 49% of the ACE variance in parents and offspring, respectively. One of these QTLs might be the I/D polymorphism itself or the newly characterized 4656(CT){sub 2/3} polymorphism. The second QTL would have a frequency of {approximately}.20, which is incompatible with any of the yet-identified polymorphisms. More extensive sequencing and extended analyses in larger samples and in other populations will be necessary to characterize definitely the functional variants. 30 refs., 1 fig., 6 tabs.« less

Angiotensin-converting enzyme inhibition and novel cardiovascular risk biomarkers: results from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN) study.

PubMed

Cesari, Matteo; Kritchevsky, Stephen B; Atkinson, Hal H; Penninx, Brenda W; Di Bari, Mauro; Tracy, Russell P; Pahor, Marco

2009-02-01

Beneficial effects of angiotensin-converting enzyme (ACE) inhibitors seem to be mediated by mechanisms that are partly independent of blood pressure lowering. The present study evaluates effects of an ACE inhibitor (ie, fosinopril) intervention on novel cardiovascular risk factors. Data are from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN) study, a double-blind, crossover, randomized, placebo-controlled trial enrolling subjects > or =55 years old with high cardiovascular disease risk profile. Biomarkers of hemostasis (ie, plasminogen activator inhibitor 1, D-dimer), inflammation (ie, C-reactive protein, interleukin-6), and endothelial function (ie, endothelin 1, vascular cell adhesion molecule 1) were measured at the baseline, at the midterm, and at end of follow-up (after 1 year) clinic visits. Paired t test analyses (after Sidak's adjustment, P < .009) were performed to compare biomarkers modifications after fosinopril/placebo interventions. Mean age of the sample (n = 290, women 43.4%) was 66.0 years old. No significant differences were reported for C-reactive protein, interleukin 6, plasminogen activator inhibitor 1, vascular cell adhesion molecule 1, and endothelin 1 levels in the comparisons between fosinopril and placebo interventions. D-dimer was the only biomarker showing a significant difference between fosinopril intervention (median 0.32 microg/mL, interquartile range 0.22-0.52 microg/mL) and placebo (median 0.29 microg/mL, interquartile range 0.20-0.47 microg/mL, P = .007) when analyses were restricted to participants with higher compliance to treatment and receiving the maximum ACE inhibitor dosage. Angiotensin-converting enzyme inhibition does not significantly modify major biomarkers of inflammation, hemostasis, and endothelial function. Further studies should confirm the possible effect of ACE inhibitors on the fibrinolysis pathway.

A systematic comparison of all mutations in hereditary sensory neuropathy type I (HSAN I) reveals that the G387A mutation is not disease associated.

PubMed

Hornemann, Thorsten; Penno, Anke; Richard, Stephane; Nicholson, Garth; van Dijk, Fleur S; Rotthier, Annelies; Timmerman, Vincent; von Eckardstein, Arnold

2009-04-01

Hereditary sensory neuropathy type 1 (HSAN I) is an autosomal dominant inherited neurodegenerative disorder of the peripheral nervous system associated with mutations in the SPTLC1 subunit of the serine palmitoyltransferase (SPT). Four missense mutations (C133W, C133Y, V144D and G387A) in SPTLC1 were reported to cause HSAN I. SPT catalyses the condensation of Serine and Palmitoyl-CoA, which is the first and rate-limiting step in the de novo synthesis of ceramides. Earlier studies showed that C133W and C133Y mutants have a reduced activity, whereas the impact of the V144D and G387A mutations on the human enzyme was not tested yet. In this paper, we show that none of the HSAN I mutations interferes with SPT complex formation. We demonstrate that also V144D has a reduced SPT activity, however to a lower extent than C133W and C133Y. In contrast, the G387A mutation showed no influence on SPT activity. Furthermore, the growth phenotype of LY-B cells--a SPTLC1 deficient CHO cell line--could be reversed by expressing either the wild-type SPTLC1 or the G387A mutant, but not the C133W mutant. This indicates that the G387A mutation is most likely not directly associated with HSAN I. These findings were genetically confirmed by the identification of a nuclear HSAN family which showed segregation of the G387A variant as a non-synonymous SNP.

Characterization of mouse and human GTP cyclohydrolase I genes. Mutations in patients with GTP cyclohydrolase I deficiency.

PubMed

Ichinose, H; Ohye, T; Matsuda, Y; Hori, T; Blau, N; Burlina, A; Rouse, B; Matalon, R; Fujita, K; Nagatsu, T

1995-04-28

GTP cyclohydrolase I is the first and rate-limiting enzyme for the biosynthesis of tetrahydrobiopterin in mammals. Previously, we reported three species of human GTP cyclohydrolase I cDNA in a human liver cDNA library (Togari, A., Ichinose, H., Matsumoto, S., Fujita, K., and Nagatsu, T. (1992) Biochem. Biophys. Res. Commun. 187, 359-365). Furthermore, very recently, we found that the GTP cyclohydrolase I gene is causative for hereditary progressive dystonia with marked diurnal fluctuation, also known as DOPA-responsive dystonia (Ichinose, H., Ohye, T., Takahashi, E., Seki, N., Hori, T., Segawa, M., Nomura, Y., Endo, K., Tanaka, H., Tsuji, S., Fujita, K., and Nagatsu, T. (1994) Nature Genetics 8, 236-242). To clarify the mechanisms that regulate transcription of the GTP cyclohydrolase I gene and to generate multiple species of mRNA, we isolated genomic DNA clones for the human and mouse GTP cyclohydrolase I genes. Structural analysis of the isolated clones revealed that the GTP cyclohydrolase I gene is encoded by a single copy gene and is composed of six exons spanning approximately 30 kilobases. We sequenced all exon/intron boundaries of the human and mouse genes. Structural analysis also demonstrated that the heterogeneity of GTP cyclohydrolase I mRNA is caused by an alternative usage of the splicing acceptor site at the sixth exon. The transcription start site of the mouse GTP cyclohydrolase I gene and the 5'-flanking sequences of the mouse and human genes were determined. We performed regional mapping of the mouse gene by fluorescence in situ hybridization, and the mouse GTP cyclohydrolase I gene was assigned to region C2-3 of mouse chromosome 14. We identified missense mutations in patients with GTP cyclohydrolase I deficiency and expressed mutated enzymes in Escherichia coli to confirm alterations in the enzyme activity.

Effect of angiotensin-converting enzyme inhibitors on vascular endothelial function in hypertensive patients after intensive periodontal treatment.

PubMed

Rubio, María C; Lewin, Pablo G; De la Cruz, Griselda; Sarudiansky, Andrea N; Nieto, Mauricio; Costa, Osvaldo R; Nicolosi, Liliana N

2016-04-01

There is a relation between vascular endothelial function, atherosclerotic disease, and inflammation. Deterioration of endothelial function has been observed twenty-four hours after intensive periodontal treatment. This effect may be counteracted by the action of angiotensin-converting enzyme inhibitors, which improve endothelial function. The aim of the present study was to evaluate vascular endothelial function after intensive periodontal treatment, in hypertensive patients treated with angiotensinconverting enzyme inhibitors. A prospective, longitudinal, comparative study involving repeated measurements was conducted. Fifty-two consecutive patients with severe periodontal disease were divided into two groups, one comprising hypertensive patients treated with converting enzyme inhibitors and the other comprising patients with no clinical signs of pathology and not receiving angiotensin-converting enzyme inhibitors. Endothelial function was assessed by measuring postischemic dilation of the humeral artery (baseline echocardiography Doppler), and intensive periodontal treatment was performed 24h later. Endothelial function was re-assessed 24h and 15 days after periodontal treatment. Results were analyzed using the SPSS 20 statistical software package. Student's t test and MANOVA were calculated and linear regression analysis with 95% confidence intervals and α<0.05 was performed. Arterial dilation at 24 hours was lower compared to baseline in both groups; values corresponding to the groups receiving angiotensin-converting enzyme inhibitors were 11.89 ± 4.87 vs. 7.30 ± 2.90% (p<0.01) and those corresponding to the group not receiving ACE inhibitors were 12.72 ± 4.62 vs. 3.56 ± 2.39 (p<0.001). The differences between groups were statistically significant (p<0.001). The increase in endothelial dysfunction after intensive periodontal treatment was significantly lower in hypertensive patients treated with angiotensin-converting enzyme inhibitors. Endothelial

Physical function is weakly associated with angiotensin-converting enzyme gene I/D polymorphism in elderly Japanese subjects.

PubMed

Yoshihara, A; Tobina, T; Yamaga, T; Ayabe, M; Yoshitake, Y; Kimura, Y; Shimada, M; Nishimuta, M; Nakagawa, N; Ohashi, M; Hanada, N; Tanaka, H; Kiyonaga, A; Miyazaki, H

2009-01-01

The turning point in the deterioration of physical function seems to occur between the ages of 70 and 80 years. In particular, muscle strength may decline even more in subjects older than 75. A recent study found that the angiotensin-converting enzyme (ACE) genotype also affects physiological left ventricular hypertrophy. A very limited number of papers have examined genetic differences in resistance and endurance forms of a single sporting discipline. The purpose of this study was to evaluate the relationship between ACE genotype and physical function by controlling the known confounding factors including dental status. We selected 431 subjects who were aged 76 years and did not require special care for their daily activities. We conducted a medical examination, followed by 5 physical function tests, as follows: (1) maximum hand grip strength, (2) maximal isometric knee extensor strength, (3) maximal stepping rate for 10 s, (4) one-leg standing time with eyes open and (5) 10-meter maximum walking speed. Subjects were genotyped for the ACE intron 16 Alu insertion. In addition, serum concentrations of total cholesterol, total protein, IgA and IgG were measured at a commercial laboratory. The Eichner index was used as an indicator of occlusal condition. Multiple linear regression analysis was performed to evaluate the relationship between the ACE gene insertion/deletion (I/D) polymorphism and physical function considering confounding factors. The ACE gene I/D polymorphism was positively associated with hand grip strength and 10-meter maximum walking speed. Betas of hand grip strength were 0.09 for I/D (p = 0.022) and 0.12 for insertion/insertion (I/I; p = 0.004). Betas of 10-meter walking speed were -0.11 for I/D (p = 0.093) and -0.14 for I/I (p = 0.039). Dental status such as Eichner index class C was significantly associated with one-leg standing time with eyes open (beta -0.11; p = 0.028). This study suggests that there is a significant relationship between ACE

Monocyte Tumor Necrosis Factor-α–Converting Enzyme Catalytic Activity and Substrate Shedding in Sepsis and Noninfectious Systemic Inflammation*

PubMed Central

O’Callaghan, David J. P.; O’Dea, Kieran P.; Scott, Alasdair J.; Takata, Masao

2015-01-01

Objectives: To determine the effect of severe sepsis on monocyte tumor necrosis factor-α–converting enzyme baseline and inducible activity profiles. Design: Observational clinical study. Setting: Mixed surgical/medical teaching hospital ICU. Patients: Sixteen patients with severe sepsis, 15 healthy volunteers, and eight critically ill patients with noninfectious systemic inflammatory response syndrome. Interventions: None. Measurements and Main Results: Monocyte expression of human leukocyte antigen-D-related peptide, sol-tumor necrosis factor production, tumor necrosis factor-α–converting enzyme expression and catalytic activity, tumor necrosis factor receptor 1 and 2 expression, and shedding at 48-hour intervals from day 0 to day 4, as well as p38-mitogen activated protein kinase expression. Compared with healthy volunteers, both sepsis and systemic inflammatory response syndrome patients’ monocytes expressed reduced levels of human leukocyte antigen-D-related peptide and released less sol-tumor necrosis factor on in vitro lipopolysaccharide stimulation, consistent with the term monocyte deactivation. However, patients with sepsis had substantially elevated levels of basal tumor necrosis factor-α–converting enzyme activity that were refractory to lipopolysaccharide stimulation and this was accompanied by similar changes in p38-mitogen activated protein kinase signaling. In patients with systemic inflammatory response syndrome, monocyte basal tumor necrosis factor-α–converting enzyme, and its induction by lipopolysaccharide, appeared similar to healthy controls. Changes in basal tumor necrosis factor-α–converting enzyme activity at day 0 for sepsis patients correlated with Acute Physiology and Chronic Health Evaluation II score and the attenuated tumor necrosis factor-α–converting enzyme response to lipopolysaccharide was associated with increased mortality. Similar changes in monocyte tumor necrosis factor-α–converting enzyme activity could

In vitro autoradiographic localization of angiotensin-converting enzyme in sarcoid lymph nodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, R.K.; Chai, S.Y.; Dunbar, M.S.

1986-09-01

Angiotensin-converting enzyme (ACE) was localized in sarcoid lymph nodes by an in vitro autoradiographic technique using a synthetic ACE inhibitor of high affinity, /sup 125/I-labelled 351A. The lymph nodes were from seven patients with active sarcoidosis who underwent mediastinoscopy and from six control subjects who had nodes resected at either mediastinoscopy or laparotomy. Angiotensin-converting enzyme was localized in the epithelioid cells of sarcoid granulomata in markedly increased amounts compared with control nodes, where it was restricted to vessels and some histiocytes. In sarcoid lymph nodes, there was little ACE present in lymphocytes or fibrous tissue. Sarcoid nodes with considerable fibrosismore » had much less intense ACE activity than the nonfibrotic nodes. The specific activity of ACE measured by an enzymatic assay in both the control and sarcoid lymph nodes closely reflected the ACE activity demonstrated by autoradiography. Sarcoid lymph nodes with fibrosis had an ACE specific activity of half that of nonfibrotic nodes (p less than 0.05). There was a 15-fold increase in specific ACE activity in sarcoid nodes (p less than 0.05) compared to normal. Serum ACE was significantly higher in those sarcoid patients whose lymph nodes were not fibrosed compared with those with fibrosis (p less than 0.01). This technique offers many advantages over the use of polyclonal antibodies. The 351A is a highly specific ACE inhibitor, chemically defined and in limitless supply. This method enables the quantitation of results, and autoradiographs may be stored indefinitely for later comparison.« less

Angiotensin-converting enzyme inhibitory activity in Mexican Fresco cheese.

PubMed

Torres-Llanez, M J; González-Córdova, A F; Hernandez-Mendoza, A; Garcia, H S; Vallejo-Cordoba, B

2011-08-01

The objective of this study was to evaluate if Mexican Fresco cheese manufactured with specific lactic acid bacteria (LAB) presented angiotensin I-converting enzyme inhibitory (ACEI) activity. Water-soluble extracts (3 kDa) obtained from Mexican Fresco cheese prepared with specific LAB (Lactococcus, Lactobacillus, Enterococcus, and mixtures: Lactococcus-Lactobacillus and Lactococcus-Enterococcus) were evaluated for ACEI activity. Specific peptide fractions with high ACEI were analyzed using reverse phase-HPLC coupled to mass spectrometry for determination of amino acid sequence. Cheese containing Enterococcus faecium or a Lactococcus lactis ssp. lactis-Enterococcus faecium mixture showed the largest number of fractions with ACEI activity and the lowest half-maximal inhibitory concentration (IC(50); <10 μg/mL). Various ACEI peptides derived from β-casein [(f(193-205), f(193-207), and f(193-209)] and α(S1)-casein [f(1-15), f(1-22), f(14-23), and f(24-34)] were found. The Mexican Fresco cheese manufactured with specific LAB strains produced peptides with potential antihypertensive activity. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The relationship between angiotensin-converting enzyme (ACE) insertion (I) / deletion (D) polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese.

PubMed

Zhang, Ya-Feng; Wang, Hong; Cheng, Qiong; Qin, Ling; Tang, Nelson Ls; Leung, Ping-Chong; Kwok, Timothy Cy

2017-01-01

In this study, we set out to investigate the relationship between angiotensin-converting enzyme ( ACE) I/D polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese. A standardized, structured, face-to-face interview was performed to collect demographic information. BMD was measured using dual-energy X-ray absorptiometry (DXA). I/D genotypes of ACE were determined by polymerase chain reaction (PCR) amplification. Serum ACE activity was determined photometrically by a commercially available kinetic kit. Multiple linear regression analysis was used to examine the relationship between ACE I/D polymorphism, serum ACE activity and BMD. A total of 1567 males and 1760 females were selected for analyzing the relationship between ACE I/D polymorphism and BMD. There was no significant difference in spine BMD, total hip BMD and femur neck BMD among different ACE I/D genotypes both in males and females. A total of 1699 males and 1739 females were selected for analyzing the relationship between serum ACE activity and BMD. There was also no significant difference in spine BMD, total hip BMD and femur neck BMD among different serum ACE activity groups both in males and females. There was no relationship between ACE I/D polymorphism, serum ACE activity and BMD in older Chinese.

Potentiation of the actions of bradykinin by angiotensin I-converting enzyme inhibitors. The role of expressed human bradykinin B2 receptors and angiotensin I-converting enzyme in CHO cells.

PubMed

Minshall, R D; Tan, F; Nakamura, F; Rabito, S F; Becker, R P; Marcic, B; Erdös, E G

1997-11-01

Part of the beneficial effects of angiotensin I-converting enzyme (ACE) inhibitors are due to augmenting the actions of bradykinin (BK). We studied this effect of enalaprilat on the binding of [3H]BK to Chinese hamster ovary (CHO) cells stably transfected to express the human BK B2 receptor alone (CHO-3B) or in combination with ACE (CHO-15AB). In CHO-15AB cells, enalaprilat (1 mumol/L) increased the total number of low-affinity [3H]BK binding sites on the cells at 37 degrees C, but not at 4 degrees C, from 18.4 +/- 4.3 to 40.3 +/- 11.9 fmol/10(6) cells (P < .05; Kd, 2.3 +/- 0.8 and 5.9 +/- 1.3 nmol/L; n = 4). Enalaprilat preserved a portion of the receptors in high-affinity conformation (Kd, 0.17 +/- 0.08 nmol/L; 8.1 +/- 0.9 fmol/10(6) cells). Enalaprilat decreased the IC50 of [Hyp3-Tyr(Me)8]BK, the BK analogue more resistant to ACE, from 3.2 +/- 0.8 to 0.41 +/- 0.16 nmol/L (P < .05, n = 3). The biphasic displacement curve of the binding of [3H]BK also suggested the presence of high-affinity BK binding sites. Enalaprilat (5 nmol to 1 mumol/L) potentiated the release of [3H]arachidonic acid and the liberation of inositol 1,4,5-trisphosphate (IP3) induced by BK and [Hyp3-Tyr(Me)8]BK. Moreover, enalaprilat (1 mumol/L) completely and immediately restored the response of the B2 receptor, desensitized by the agonist (1 mumol/L [Hyp3-Tyr(Me)8]BK); this effect was blocked by the antagonist, HOE 140. Finally, enalaprilat, but not the prodrug enalapril, decreased internalization of the receptor from 70 +/- 9% to 45 +/- 9% (P < .05, n = 7). In CHO-3B cells, enalaprilat was ineffective. ACE inhibitors in the presence of both the B2 receptor and ACE enhance BK binding, protect high-affinity receptors, block receptor desensitization, and decrease internalization, thereby potentiating BK beyond blocking its hydrolysis.

Polymorphism of angiotensin-converting enzyme gene in sarcoidosis.

PubMed

Arbustini, E; Grasso, M; Leo, G; Tinelli, C; Fasani, R; Diegoli, M; Banchieri, N; Cipriani, A; Gorrini, M; Semenzato, G; Luisetti, M

1996-02-01

Sarcoidosis is the disease in which increased levels of serum Angiotensin-converting enzyme (sACE) are most often detected. It has recently been shown that the deletion (D) or the insertion (I) of a 250bp-DNA fragment in the ACE gene accounts for three main ACE genotypes (i.e., II, ID, and DD) and for 47% of total phenotypic variance in sACE level. The aim of our work was to investigate whether or not patients with sarcoidosis have an increased incidence of those ACE genotypes coding for highest sACE levels and to investigate whether or not sACE level in sarcoidosis is related to ACE genotypes. We studied 61 unrelated patients with sarcoidosis (test group) and 80 unrelated healthy control subjects (control group). The ACE I and D alleles were detected with polymerase chain reaction on genomic DNA. In the control group we found an ACE genotype distribution that agreed with the Hardy-Weinberg proportion. The ACE genotype distribution was not significantly different in the test group. There was no correlation between ACE genotype and roentgenologic stage of sarcoidosis. Plotting the sACE level in the control group against ACE genotype, we found a trend of increasing mean sACE value according to the order II < ID < DD. The same trend for ACE genotype was found in the test group, in which it also paralleled the trend of sACE values plotted against roentgenologic stage, according to the order Stage I < Stage II < Stage III. We conclude that in sarcoidosis the ACE genotype distribution is not altered. The trends for increasing sACE values in sarcoidosis according to both ACE genotype and roentgenologic stage would suggest that both mechanisms play a role in determining sACE level.

Dihydroquercetin Does Not Affect Age-Dependent Increase in Blood Pressure and Angiotensin-Converting Enzyme Activity in the Aorta of Hypertensive Rats.

PubMed

Slashcheva, G A; Rykov, V A; Lobanov, A V; Murashev, A N; Kim, Yu A; Arutyunyan, T V; Korystova, A F; Kublik, L N; Levitman, M Kh; Shaposhnikona, V V; Korystov, Yu N

2016-09-01

We analyzed changes in angiotensin-converting enzyme activity in the aorta of hypertensive SHR rats against the background of age-related BP increase (from week 7 to 14) and the effect of dihydroquercetin on BP rise and angiotensin-converting enzyme activity. Normotensive WKY rats of the same age were used as the control. BP and activity of angiotensin-converting enzyme in the aorta of SHR rats increased with age. Dihydroquercetin in doses of 100 and 300 μg/kg per day had no effect on the increase of these parameters; dihydroquercetin administered to 14-week-old WKY rats in a dose of 300 μg/kg reduced activity of the angiotensin-converting enzyme. Thus, the early (7-14 weeks) increase in BP and angiotensin-converting enzyme activity in the aorta of SHR rats was not modified by flavonoids (dihydroquercetin) in contrast to other rat strains and humans, which is indicative of specificity of hypertension mechanism in SHR rats.

The evaluation of angiotensin-converting enzyme (ACE) gene I/D and IL-4 gene intron 3 VNTR polymorphisms in coronary artery disease.

PubMed

Basol, Nursah; Celik, Atac; Karakus, Nevin; Ozturk, Sibel Demir; Ozsoy, Sibel Demir; Yigit, Serbulent

2014-01-01

Genetic polymorphism is a strong risk factor for coronary artery disease (CAD). In the present study, our aim was to evaluate angiotensin-converting enzyme (ACE) gene I/D polymorphism and interleukin-4 (IL-4) gene Intron 3 variable number of tandem repeat (VNTR) polymorphism in CAD. One hundred and twenty-four CAD patients and one hundred and twenty-three controls were enrolled. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR) analyses. The risk associated with inheriting the combined genotypes for the two polymorphisms were evaluated and it was found that the individuals who were P2P2-homozygous at IL-4 gene intron 3 VNTR and DD-homozygous at ACE gene I/D have a higher risk of developing CAD. Although, there is no correlation between IL4 VNTR polymorphism and ACE gene polymorphism and CAD, there is a strong association between CAD and co-existence of IL-4 VNTR and ACE gene polymorphisms in the Turkish population. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Meta analysis of angiotensin-converting enzyme I/D polymorphism as a risk factor for preeclampsia in Chinese women.

PubMed

Zhong, W G; Wang, Y; Zhu, H; Zhao, X

2012-08-13

Preeclampsia affects 3-8% of pregnancies and is a major cause of maternal and perinatal morbidity and mortality worldwide. Inappropriate activation of the renin-angiotensin system may play a role in the development of preeclampsia. An insertion/deletion polymorphism in the angiotensin-converting enzyme gene (ACE-I/D) has been associated with differences in ACE activity. However, there are controversies in reports on the association of ACE-I/D with preeclampsia. Data were analyzed using Review Manager Version 5.0 and a random effects model was applied irrespective of between studies heterogeneity, which was evaluated via sensitivity and subgroup analyses. Publication bias was evaluated using the fail-safe number. A systematic search was performed based on published case control studies up to October 1, 2011, and 11 studies were included, involving 800 patients and 949 controls. Significant association of the ACE D allele with increase risk of preeclampsia was found (odds ratio = 1.93, 95% confidence interval = 1.19-3.12; P = 0.008). Sensitivity analysis showed that no individual study had an undue influence on the summary odds ratios for all contrasts. An analysis stratified by study size showed an attenuated odds ratio towards a null effect as study size increased. Based on our meta-analysis, we suggest that the D allele of the ACE gene is related with increased risk for preeclampsia in the Chinese population. Considering the potential existence of small study bias, further research should be performed with a larger dataset.

Identification of natural inhibitors against angiotensin I converting enzyme for cardiac safety using induced fit docking and MM-GBSA studies

PubMed Central

Vijayakumar, Balakrishnan; Parasuraman, Subramani; Raveendran, Ramasamy; Velmurugan, Devadasan

2014-01-01

Background: Cleistanthins A and B are isolated compounds from the leaves of Cleistanthus collinus Roxb (Euphorbiaceae). This plant is poisonous in nature which causes cardiovascular abnormalities such as hypotension, nonspecific ST-T changes and QTc prolongation. The biological activity predictions spectra of the compounds show the presence of antihypertensive, diuretic and antitumor activities. Objective: Objective of the present study was to determine the in silico molecular interaction of cleistanthins A and B with Angiotensin I- Converting Enzyme (ACE-I) using Induced Fit Docking (IFD) protocols. Materials and Methods: All the molecular modeling calculations like IFD docking, binding free energy calculation and ADME/Tox were carried out using Glide software (Schrödinger LLC 2009, USA) in CentOS EL-5 workstation. Results: The IFD complexes showed favorable docking score, glide energy, glide emodel, hydrogen bond and hydrophobic interactions between the active site residues of ACE-I and the compounds. Binding free energy was calculated for the IFD complexes using Prime MM-GBSA method. The conformational changes induced by the inhibitor at the active site of ACE-I were observed based on changes of the back bone Cα atoms and side-chain chi (x) angles. The various physicochemical properties were calculated for these compounds. Both cleistanthins A and B showed better docking score, glide energy and glide emodel when compared to captopril inhibitor. Conclusion: These compounds have successively satisfied all the in silico parameters and seem to be potent inhibitors of ACE-I and potential candidates for hypertension. PMID:25298685

Investigation into the Mechanism of Homo- and Heterodimerization of Angiotensin-Converting Enzyme.

PubMed

Abrie, J Albert; Moolman, Wessel J A; Cozier, Gyles E; Schwager, Sylva L; Acharya, K Ravi; Sturrock, Edward D

2018-04-01

Angiotensin-converting enzyme (ACE) plays a central role in the renin-angiotensin system (RAS), which is primarily responsible for blood pressure homeostasis. Studies have shown that ACE inhibitors yield cardiovascular benefits that cannot be entirely attributed to the inhibition of ACE catalytic activity. It is possible that these benefits are due to interactions between ACE and RAS receptors that mediate the protective arm of the RAS, such as angiotensin II receptor type 2 (AT 2 R) and the receptor MAS. Therefore, in this study, we investigated the molecular interactions of ACE, including ACE homodimerization and heterodimerization with AT 2 R and MAS, respectively. Molecular interactions were assessed by fluorescence resonance energy transfer and bimolecular fluorescence complementation in human embryonic kidney 293 cells and Chinese hamster ovary-K1 cells transfected with vectors encoding fluorophore-tagged proteins. The specificity of dimerization was verified by competition experiments using untagged proteins. These techniques were used to study several potential requirements for the germinal isoform of angiotensin-converting enzyme expressed in the testes (tACE) dimerization as well as the effect of ACE inhibitors on both somatic isoforms of angiotensin-converting enzyme expressed in the testes (sACE) and tACE dimerization. We demonstrated constitutive homodimerization of sACE and of both of its domains separately, as well as heterodimerization of both sACE and tACE with AT 2 R, but not MAS. In addition, we investigated both soluble sACE and the sACE N domain using size-exclusion chromatography-coupled small-angle X-ray scattering and we observed dimers in solution for both forms of the enzyme. Our results suggest that ACE homo- and heterodimerization does occur under physiologic conditions. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Application of liquid chromatography-electrospray ionization mass spectrometry for study of steroid-converting enzymes.

PubMed

Miksík, Ivan; Mikulíková, Katerina; Pácha, Jirí; Kucka, Marek; Deyl, Zdenek

2004-02-05

A high-performance liquid chromatography-atmospheric pressure ionization-electrospray ionization mass spectrometry (HPLC-API-ESI-MS) method was developed for the analysis of steroids in a study of steroid-converting enzymes. Separations ware done on a Zorbax Eclipse XDB-C18 column (eluted with a linear methanol-water-acetic acid gradient) and identification of the steroids involved was done by API-ESI-MS using positive ion mode and extracted ion analysis. The applicability of the present method for studying steroid metabolism was proven in assaying two steroid-converting enzymes (20beta-hydroxysteroid dehydrogenase and 11beta-hydroxysteroid dehydrogenase) in various biological samples (rat and chicken intestine, chicken oviduct).

Angiotensin converting enzyme immobilized on magnetic beads as a tool for ligand fishing.

PubMed

de Almeida, Fernando G; Vanzolini, Kenia L; Cass, Quezia B

2017-01-05

Angiotensin converting enzyme (ACE) presents an important role in blood pressure regulation, since that converts angiotensin I to the vasoconstrictor angiotensin II. Some commercially available ACE inhibitors are captopril, lisinopril and enalapril; due to their side effects, naturally occurring inhibitors have been prospected. In order to endorse this research field we have developed a new tool for ACE ligand screening. To this end, ACE was extracted from bovine lung, purified and chemically immobilized in modified ferrite magnetic beads (ACE-MBs). The ACE-MBs have shown a Michaelian kinetic behavior towards hippuryl-histidyl-leucine. Moreover, as proof of concept, the ACE-MBs was inhibited by lisinopril with a half maximal inhibitory concentration (IC 50 ) of 10nM. At the fishing assay, ACE-MBs were able not only to fish out the reference inhibitor, but also one peptide from a pool of tryptic digested BSA. In conclusion, ACE-MBs emerge as new straightforward tool for ACE kinetics determination, inhibition and binder screening. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectrum of mutations in Glutaryl-CoA dehydrogenase gene in glutaric aciduria type I--Study from South India.

PubMed

Radha Rama Devi, A; Ramesh, Vakkalagadda A; Nagarajaram, H A; Satish, S P S; Jayanthi, U; Lingappa, Lokesh

2016-01-01

Glutaric aciduria type I is an autosomal recessive organic acid disorder. The primary defect is the deficiency of Glutaryl-CoA dehydrogenase (EC number 1.3.99.7) enzyme that is involved in the catabolic pathways of the amino acids l-lysine, l-hydroxylysine, and l-tryptophan. It is a treatable neuro-metabolic disorder. Early diagnosis and treatment helps in preventing brain damage. The Glutaryl-CoA dehydrogenase gene (GCDH) gene was sequenced to identify disease causing mutations by direct sequencing of all the exons in twelve patients who were biochemically confirmed with GA I. We identified eleven mutations of which nine are homozygous mutations, one heterozygous and two synonymous mutations. Among the eleven mutations, four mutations p.Q162R, p.P286S, p.W225X in two families and p.V410M are novel. A milder clinical presentation is observed in those families who are either heterozygous or with a benign synonymous SNP. Multiple sequence alignment (MSA) of GCDH with its homologues revealed that the observed novel mutations are not tolerated by protein structure and function. The present study indicates genetic heterogeneity in GCDH gene mutations among South Indian population. Genetic analysis is useful in prenatal diagnosis and prevention. Mutation analysis is a useful tool in the absence of non-availability of enzyme assay in GA I. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Apricot and other seed stones: amygdalin content and the potential to obtain antioxidant, angiotensin I converting enzyme inhibitor and hypocholesterolemic peptides.

PubMed

García, M C; González-García, E; Vásquez-Villanueva, R; Marina, M L

2016-11-09

Stones from olives and Prunus genus fruits are cheap and sustainable sources of proteins and could be potential sources of bioactive peptides. The main limitation to the use of these seeds is the presence of amygdalin. This work proposes to determine amygdalin in olive and Prunus seeds and in protein isolates obtained from them. Moreover, antioxidant, angiotensin I converting enzyme (ACE) inhibitor, and hypocholesterolemic properties will be evaluated in hydrolysates obtained from these seeds. Despite some seeds contained amygdalin, all protein isolates were free of this substance. Two different procedures to obtain bioactive peptides from protein isolates were examined: gastrointestinal digestion and processing with Alcalase, Flavourzyme or Thermolysin. Higher antioxidant, ACE inhibitor and hypocholesterolemic activities were observed when proteins were processed with Alcalase, Flavourzyme or Thermolysin. The highest antioxidant and ACE inhibitor capacities were observed for the Prunus genus seed hydrolysates while the highest capacity to reduce micellar cholesterol solubility was observed for the apricot and olive seed hydrolysates.

Cognitive enhancing effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on learning and memory

PubMed Central

Nade, V. S.; Kawale, L. A.; Valte, K. D.; Shendye, N. V.

2015-01-01

Objective: The present study was designed to investigate cognitive enhancing property of angiotensin-converting enzymes inhibitors (ACEI) and angiotensin receptor blockers (ARBs) in rats. Materials and Methods: The elevated plus maze (EPM), passive avoidance test (PAT), and water maze test (WMT) were used to assess cognitive enhancing activity in young and aged rats. Ramipril (10 mg/kg, p.o.), perindopril (10 mg/kg, i.p), losartan (20 mg/kg, i.p), and valsartan (20 mg/kg, p.o) were administered to assess their effect on learning and memory. Scopolamine (1 mg/kg, i.p) was used to impair cognitive function. Piracetam (200 mg/kg, i.p) was used as reference drug. Results: All the treatments significantly attenuated amnesia induced by aging and scopolamine. In EPM, aged and scopolamine-treated rats showed an increase in transfer latency (TL) whereas, ACEI and ARBs showed a significant decrease in TL. Treatment with ACEI and ARBs significantly increased step down latencies and decreased latency to reach the platform in target quadrant in young, aged and scopolamine-treated animals in PAT and WMT, respectively. The treatments inhibited acetylcholinesterase (AChE) enzyme in the brain. Similarly, all the treatments attenuated scopolamine-induced lipid peroxidation and normalize antioxidant enzymes. Conclusion: The results suggest that the cognitive enhancing effect of ACEI and ARBs may be due to inhibition of AChE or by regulation of antioxidant system or increase in formation of angiotensin IV. PMID:26069362

Angiotensin I converting enzyme inhibitory activity and antihypertensive effect in spontaneously hypertensive rats of cobia (Rachycentron canadum) head papain hydrolysate.

PubMed

Yang, Ping; Jiang, Yuchuan; Hong, Pengzhi; Cao, Wenhong

2013-06-01

Cobia head protein hydrolysate (CHPH) with angiotensin I converting enzyme (ACE) inhibitory activity was prepared with papain. The 3 kDa ultrafiltration filtrate CHPH-IV of the hydrolysate exerted a potent ACE inhibitory activity with IC50 being 0.24 mg/mL. The fractions with molecular weight located between 1749 Da and 173 Da represented up 66.96% of CHPH-IV, and those between 494 Da and 173 Da represented up 31.37% of CHPH-IV. It was found that the ACE inhibitory activity of CHPH-IV was intensified from IC50 0.24 mg/mL to 0.17 mg/mL after incubation with gastrointestinal proteases. The CHPH-IV significantly decreased the systolic blood pressure in a dose-dependent manner after oral administration to spontaneously hypertensive rats (SHR) at dose of 150 mg/kg, 600 mg/kg and 1200 mg/kg body weight. These results suggested that CHPH-IV from cobia head protein hydrolysate by papain could serve as a source of peptides with antihypertensive activity in functional food industry.

Antihypertensive Effects, Molecular Docking Study, and Isothermal Titration Calorimetry Assay of Angiotensin I-Converting Enzyme Inhibitory Peptides from Chlorella vulgaris.

PubMed

Xie, Jingli; Chen, Xujun; Wu, Junjie; Zhang, Yanyan; Zhou, Yan; Zhang, Lujia; Tang, Ya-Jie; Wei, Dongzhi

2018-02-14

The aim of this work is to explore angiotensin I-converting enzyme (ACE) inhibitory peptides from Chlorella vulgaris (C. vulgaris) and discover the inhibitory mechanism of the peptides. After C. vulgaris proteins were gastrointestinal digested in silico, several ACE inhibitory peptides with C-terminal tryptophan were screened. Among them, two novel noncompetitive ACE inhibitors, Thr-Thr-Trp (TTW) and Val-His-Trp (VHW), exhibited the highest inhibitory activity indicated by IC 50 values 0.61 ± 0.12 and 0.91 ± 0.31 μM, respectively. Both the peptides were demonstrated stable against gastrointestinal digestion and ACE hydrolysis. The peptides were administrated to spontaneously hypertensive rats (SHRs) in the dose 5 mg/kg body weight, and VHW could decrease 50 mmHg systolic blood pressure of SHRs (p < 0.05). Molecular docking displayed that both TTW and VHW formed six hydrogen bonds with active site pockets of ACE. Besides, isothermal titration calorimetry assay discovered that VHW could form more stable complex with ACE than TTW. Therefore, VHW was an excellent ACE inhibitor.

The effect of structural motifs on the ectodomain shedding of human angiotensin-converting enzyme.

PubMed

Conrad, Nailah; Schwager, Sylva L U; Carmona, Adriana K; Sturrock, Edward D

2016-12-02

Somatic angiotensin converting enzyme (sACE) is comprised of two homologous domains (N and C domains), whereas the smaller germinal isoform (tACE) is identical to the C domain. Both isozymes share an identical stalk, transmembrane and cytoplasmic domain, and undergo ectodomain shedding by an as yet unknown protease. Here we present evidence for the role of regions distal and proximal to the cleavage site in human ACE shedding. First, because of intrinsic differences between the N and C domains, discrete secondary structures (α-helix 7 and 8) on the surface of tACE were replaced with their N domain counterparts. Surprisingly, neither α-helix 7 nor α-helix 8 proved to be an absolute requirement for shedding. In the proximal ectodomain of tACE residues H 610 -L 614 were mutated to alanines and this resulted in a decrease in ACE shedding. An N-terminal extension of this mutation caused a reduction in cellular ACE activity. More importantly, it affected the processing of the protein to the membrane, resulting in expression of an underglycosylated form of ACE. When E 608 -H 614 was mutated to the homologous region of the N domain, processing was normal and shedding only moderately decreased suggesting that this region is more crucial for the processing of ACE than it is for regulating shedding. Finally, to determine whether glycosylation of the asparagine proximal to the Pro1199-Leu polymorphism in sACE affected shedding, the equivalent P 623 L mutation in tACE was investigated. The P 623 L tACE mutant showed an increase in shedding and MALDI MS analysis of a tryptic digest indicated that N 620 WT was glycosylated. The absence of an N-linked glycan at N 620 , resulted in an even greater increase in shedding. Thus, the conformational flexibility that the leucine confers to the stalk, is increased by the lack of glycosylation reducing access of the sheddase to the cleavage site. Copyright © 2016 Elsevier Inc. All rights reserved.

The Design and Development of a Potent and Selective Novel Diprolyl Derivative That Binds to the N-Domain of Angiotensin-I Converting Enzyme.

PubMed

Fienberg, Stephen; Cozier, Gyles E; Acharya, K Ravi; Chibale, Kelly; Sturrock, Edward D

2018-01-11

Angiotensin-I converting enzyme (ACE) is a zinc metalloprotease consisting of two catalytic domains (N- and C-). Most clinical ACE inhibitor(s) (ACEi) have been shown to inhibit both domains nonselectively, resulting in adverse effects such as cough and angioedema. Selectively inhibiting the individual domains is likely to reduce these effects and potentially treat fibrosis in addition to hypertension. ACEi from the GVK Biosciences database were inspected for possible N-domain selective binding patterns. From this set, a diprolyl chemical series was modeled using docking simulations. The series was expanded based on key target interactions involving residues known to impart N-domain selectivity. In total, seven diprolyl compounds were synthesized and tested for N-domain selective ACE inhibition. One compound with an aspartic acid in the P 2 position (compound 16) displayed potent inhibition (K i = 11.45 nM) and was 84-fold more selective toward the N-domain. A high-resolution crystal structure of compound 16 in complex with the N-domain revealed the molecular basis for the observed selectivity.

In Vitro Studies on the Antioxidant Property and Inhibition of α-Amylase, α-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean

PubMed Central

Ademosun, Ayokunle O.; Ademiluyi, Adedayo O.; Omojokun, Olasunkanmi S.; Nwanna, Esther E.; Longe, Kuburat O.

2014-01-01

Background. This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa (Theobroma cacao) bean through inhibition of α-amylase, α-glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology. The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro. Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results. The results revealed that the extract inhibited α-amylase (1.81 ± 0.22 mg/mL), α-glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC·g] scavenging ability. Conclusion. The inhibition of α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension. PMID:25295218

In Vitro Studies on the Antioxidant Property and Inhibition of α-Amylase, α-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean.

PubMed

Oboh, Ganiyu; Ademosun, Ayokunle O; Ademiluyi, Adedayo O; Omojokun, Olasunkanmi S; Nwanna, Esther E; Longe, Kuburat O

2014-01-01

Background. This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa (Theobroma cacao) bean through inhibition of α-amylase, α-glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology. The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro. Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results. The results revealed that the extract inhibited α-amylase (1.81 ± 0.22 mg/mL), α-glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC·g] scavenging ability. Conclusion. The inhibition of α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension.

21 CFR 862.1090 - Angiotensin converting enzyme (A.C.E.) test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Angiotensin converting enzyme (A.C.E.) test system. 862.1090 Section 862.1090 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

21 CFR 862.1090 - Angiotensin converting enzyme (A.C.E.) test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Angiotensin converting enzyme (A.C.E.) test system. 862.1090 Section 862.1090 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

21 CFR 862.1090 - Angiotensin converting enzyme (A.C.E.) test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Angiotensin converting enzyme (A.C.E.) test system. 862.1090 Section 862.1090 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

21 CFR 862.1090 - Angiotensin converting enzyme (A.C.E.) test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Angiotensin converting enzyme (A.C.E.) test system. 862.1090 Section 862.1090 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

Forkhead Box Transcription Factors of the FOXA Class Are Required for Basal Transcription of Angiotensin-Converting Enzyme 2

PubMed Central

Pedersen, Kim Brint; Chodavarapu, Harshita

2017-01-01

Angiotensin-converting enzyme 2 (ACE2) has protective effects on a wide range of morbidities associated with elevated angiotensin-II signaling. Most tissues, including pancreatic islets, express ACE2 mainly from the proximal promoter region. We previously found that hepatocyte nuclear factors 1α and 1β stimulate ACE2 expression from three highly conserved hepatocyte nuclear factor 1 binding motifs in the proximal promoter region. We hypothesized that other highly conserved motifs would also affect ACE2 expression. By systematic mutation of conserved elements, we identified five regions affecting ACE2 expression, of which two regions bound transcriptional activators. One of these is a functional FOXA binding motif. We further identified the main protein binding the FOXA motif in 832/13 insulinoma cells as well as in mouse pancreatic islets as FOXA2. PMID:29082356

I1171 missense mutation (particularly I1171N) is a common resistance mutation in ALK-positive NSCLC patients who have progressive disease while on alectinib and is sensitive to ceritinib.

PubMed

Ou, Sai-Hong Ignatius; Greenbowe, Joel; Khan, Ziad U; Azada, Michele C; Ross, Jeffrey S; Stevens, Phil J; Ali, Siraj M; Miller, Vincent A; Gitlitz, Barbara

2015-05-01

Acquired resistance mutations to anaplastic lymphoma kinase (ALK) inhibitors such as crizotinib and alectinib have been documented in non-small cell lung cancer (NSCLC) patients harboring ALK rearrangement (ALK+). Of note I1171T/N/S mutations in the ALK kinase domain have recently been described by several groups to confer resistance to alectinib, a second-generation ALK inhibitor. Additionally one of these reports demonstrated one ALK+ NSCLC patient harboring an I1171T acquired mutation has responded to ceritinib, another second-generation ALK inhibitor. We reported the presence of an ALK I1171N resistance mutation from comprehensive genomic profiling from a liver biopsy of a progressing metastatic lesion in an ALK+ patient on alectinib after an initial partial response. The patient then responded to ceritinib 750 mg orally once daily but required dose reduction to 600 mg once daily. She initially had grade 3 elevation of liver enzymes from crizotinib necessitating the original switch to alectinib but experienced no transaminase elevations with alectinib or ceritinib. This is the fifth patient case to date demonstrating that ALK I1171 mutation confers resistance to alectinib and the second reported case of ALK I1171 mutation being sensitivity to ceritinib. Substitutions of isoleucine at amino acid 1171 in the ALK kinase domain may distinguish which second generation ALK inhibitor will be effective after crizotinib failure. This case also provides evidence that transaminase elevations is likely a unique adverse event associated with crizotinib and unlikely a "class" effect involving all ALK inhibitors. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Mucopolysaccharidosis type I in 21 Czech and Slovak patients: Mutation analysis suggests a functional importance of C-terminus of the IDUA protein

PubMed Central

Vazna, Alzbeta; Beesley, Clare; Berna, Linda; Stolnaja, Larisa; Myskova, Helena; Bouckova, Michaela; Vlaskova, Hana; Poupetova, Helena; Zeman, Jiri; Magner, Martin; Hlavata, Anna; Winchester, Bryan; Hrebicek, Martin; Dvorakova, Lenka

2009-01-01

Abstract Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder that is caused by a deficiency of the enzyme α-l-iduronidase (IDUA). Of the 21 Czech and Slovak patients who have been diagnosed with MPS I in the last 30 years, 16 have a severe clinical presentation (Hurler syndrome), 2 less severe manifestations (Scheie syndrome), and 3 an intermediate severity (Hurler/Scheie phenotype). Mutation analysis was performed in 20 MPS I patients and 39 mutant alleles were identified. There was a high prevalence of the null mutations p.W402X (12 alleles) and p.Q70X (7 alleles) in this cohort. Four of the 13 different mutations were novel: p.V620F (3 alleles), p.W626X (1 allele), c.1727 + 2T > G (1 allele) and c.1918_1927del (2 alleles). The pathogenicity of the novel mutations was verified by transient expression studies in Chinese hamster ovary cells. Seven haplotypes were observed in the patient alleles using 13 intragenic polymorphisms. One of the two haplotypes associated with the mutation p.Q70X was not found in any of the controls. Haplotype analysis showed, that mutations p.Q70X, p.V620F, and p.D315Y probably have more than one ancestor. Missense mutations localized predominantly in the hydrophobic core of the enzyme are associated with the severe phenotype, whereas missense mutations localized to the surface of the enzyme are usually associated with the attenuated phenotypes. Mutations in the 130 C-terminal amino acids lead to clinical manifestations, which indicates a functional importance of the C-terminus of the IDUA protein. © 2009 Wiley-Liss, Inc. PMID:19396826

[Association between visual improvement after photocoagulation and the use of angiotensin converting enzyme inhibitors in diabetic macular oedema].

PubMed

Somilleda-Ventura, Selma Alin; García-Rubio, Yatzul Zuhaila; Razo Blanco-Hernández, Dulce Milagros; Lima-Gómez, Virgilio

2016-01-01

Angiotensin converting enzyme inhibitors are effective in delaying the progression of diabetic retinopathy. It is unknown if their use is associated with a better visual outcome in patients with diabetic macular oedema. A non-experimental, comparative, longitudinal and retrospective study was performed on patients with diabetic macular oedema treated by focal photocoagulation, and with systemic arterial hypertension treated with angiotensin converting enzyme inhibitors (Group 1), and without hypertension (Group 2). The dependent variable was the proportion with visual improvement, operatively defined as the gain of one or more lines of vision three weeks after photocoagulation. The independent variable was the use of angiotensin converting enzyme inhibitors. The proportion of eyes with visual improvement after treatment was compared between groups using the Chi squared (χ(2)) test. A total of 33 eyes (51.6%) were assigned to group 1, and 31 (48.2%), to group 2. The mean of visual acuity improved after three weeks, compared with baseline (p=0.002). The proportion of eyes with visual improvement did not differ between patients treated with angiotensin converting enzyme inhibitors (45.5%) and those that did not use them (51.6%, p=0.4). There was no statistical difference in the proportion of eyes with visual improvement between patients treated with angiotensin converting enzyme inhibitors and in those where they were not used. There is no support for the inhibition of angiotensin II in addition to photocoagulation for improving the outcome in patients with diabetic macular oedema. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Somatic isoform of angiotensin I-converting enzyme in the pathology of testicular germ cell tumors.

PubMed

Franke, F E; Pauls, K; Kerkman, L; Steger, K; Klonisch, T; Metzger, R; Alhenc-Gelas, F; Burkhardt, E; Bergmann, M; Danilov, S M

2000-12-01

Retained fetal expression of angiotensin I-converting enzyme (ACE, CD143) has recently been shown in intratubular germ cell neoplasms (IGCN) and invasive germ cell tumors (GCT), suggesting the somatic isoform (sACE) as a characteristic component of neoplastic germ cells. We analyzed the distribution of sACE in 159 testicular GCT, including 87 IGCN. sACE protein was determined by immunohistochemistry (MAb CG2) on routinely formalin-fixed and paraffin-embedded tissue sections, supplemented by mRNA expression analysis using in situ hybridization. These data were compared with those obtained by germ cell/placental alkaline phosphatases (PIAP; MAbs PL8-F6 and 8A9) employing an uniform score system for the evaluation of immunoreactivity (IRS; possible values from 0 to 12). Expression of sACE and PIAP was found in all 87 analyzed IGCN (IRS > 4, median IRS of 12). Heterogeneous staining patterns were not related to the type of adjacent GCT but correlated with low expression in adjacent seminomas (P =.032 for sACE; P =.005 for PIAP). Both sACE and PIAP often showed a decreased and more heterogeneous but still moderate expression in 91 classic seminomas (median IRS of 8) and were completely absent in tumor cells of spermatocytic seminomas. Despite all similarities, we found sACE and PIAP differently regulated during GCT progression. This was documented by a well-preserved expression of either sACE or PIAP or both in all classic seminomas, low PIAP immunoreactivity in metastasis of seminomas, and completely diverging expression patterns in nonseminomatous GCT. Our findings underline the close molecular relationship between IGCN and seminoma, and suggest sACE as an appropriate marker for seminomatous differentiated tumors. HUM PATHOL 31:1466-1476. Copyright 2000 by W.B. Saunders Company

Characterization of phospholipase C gamma enzymes with gain-of-function mutations.

PubMed

Everett, Katy L; Bunney, Tom D; Yoon, Youngdae; Rodrigues-Lima, Fernando; Harris, Richard; Driscoll, Paul C; Abe, Koichiro; Fuchs, Helmut; de Angelis, Martin Hrabé; Yu, Philipp; Cho, Wohnwa; Katan, Matilda

2009-08-21

Phospholipase C gamma isozymes (PLC gamma 1 and PLC gamma 2) have a crucial role in the regulation of a variety of cellular functions. Both enzymes have also been implicated in signaling events underlying aberrant cellular responses. Using N-ethyl-N-nitrosourea (ENU) mutagenesis, we have recently identified single point mutations in murine PLC gamma 2 that lead to spontaneous inflammation and autoimmunity. Here we describe further, mechanistic characterization of two gain-of-function mutations, D993G and Y495C, designated as ALI5 and ALI14. The residue Asp-993, mutated in ALI5, is a conserved residue in the catalytic domain of PLC enzymes. Analysis of PLC gamma 1 and PLC gamma 2 with point mutations of this residue showed that removal of the negative charge enhanced PLC activity in response to EGF stimulation or activation by Rac. Measurements of PLC activity in vitro and analysis of membrane binding have suggested that ALI5-type mutations facilitate membrane interactions without compromising substrate binding and hydrolysis. The residue mutated in ALI14 (Tyr-495) is within the spPH domain. Replacement of this residue had no effect on folding of the domain and enhanced Rac activation of PLC gamma 2 without increasing Rac binding. Importantly, the activation of the ALI14-PLC gamma 2 and corresponding PLC gamma 1 variants was enhanced in response to EGF stimulation and bypassed the requirement for phosphorylation of critical tyrosine residues. ALI5- and ALI14-type mutations affected basal activity only slightly; however, their combination resulted in a constitutively active PLC. Based on these data, we suggest that each mutation could compromise auto-inhibition in the inactive PLC, facilitating the activation process; in addition, ALI5-type mutations could enhance membrane interaction in the activated state.

Synthesis and evaluation of chalcone analogues based pyrimidines as angiotensin converting enzyme inhibitors.

PubMed

Bukhari, S N A; Butt, A M; Amjad, M W B; Ahmad, W; Shah, V H; Trivedi, A R

2013-11-01

Hypertension is a widespread and frequently progressive ailment that imparts a foremost threat for cardiovascular and renal disorders. Mammoth efforts are needed for the synthesis of innovative antihypertensive agents to combat this lethal disease. Chalcones have shown antihypertensive activity through inhibition of Angiotensin Converting Enzyme (ACE). Hence, a series of chalcone analogues is synthesized and used as precursor for the synthesis of novel series of pyrimidines. Precursor chalcones were prepared by reacting aldehydes and ketones in presence of sodium hydroxide followed by synthesis of corresponding pyrimidines by reaction with urea in presence of potassium hydroxide. Both groups were then evaluated for their effects on ACE. The results depicted that pyrimidines were more active than chalcones with methoxy (C5 and P5) substitution showing best results to inhibit ACE. Given that chalcone analogues and pyrimidines show a potential as the angiotensin converting enzyme inhibitors.

Lactic acid bacteria: inhibition of angiotensin converting enzyme in vitro and in vivo.

PubMed

Fuglsang, Anders; Rattray, Fergal P; Nilsson, Dan; Nyborg, Niels C B

2003-01-01

A total of 26 strains of wild-type lactic acid bacteria, mainly belonging to Lactococcus lactis and Lactobacillus helveticus, were assayed in vitro for their ability to produce a milk fermentate with inhibitory activity towards angiotensin converting enzyme (ACE). It was clear that the test strains in this study, in general, produce inhibitory substances in varying amounts. Using a spectrophotometric assay based on amino group derivatization with ortho-phthaldialdehyde as a measure of relative peptide content, it was shown that there is a significant correlation between peptide formation and ACE inhibition, indicating that peptide measurement constitutes a convenient selection method. The effect of active fermentates on in vivo ACE activity was demonstrated in normotensive rats. The pressor effect of angiotensin I (0.3 microg/kg) upon intravenous injection was significantly lower when rats were pre-fed with milks fermented using two strains of Lactobacillus helveticus. An increased response to bradykinin (10 microg/kg, intravenously injected) was observed using one of these fermented milks. It is concluded that Lactobacillus helveticus produces substances which in vivo can give rise to an inhibition of ACE. The inhibition in vivo was low compared to what can be achieved with classical ACE inhibitors. The clinical relevance of this finding is discussed. This work is the first in which an effect of fermented milk on ACE in vivo has been demonstrated, measured as decreased ability to convert angiotensin I to angiotensin II.

Marketing research on the angiotensin-converting enzyme inhibitors antihypertensive medicines.

PubMed

Boboia, Anamaria; Grigorescu, Marius Rareş; Turcu-Ştiolică, Adina

2017-01-01

The research aimed at investigating sales trends of angiotensin-converting enzyme inhibitors antihypertensive medicines, both in terms of quantity and value, in ten community pharmacies, for a period of three years. The research on the antihypertensive medicines consumption is important for highlighting the ever increasing impact of hypertension among the population. The methods used in this research were the following: marketing research, method of sampling, descriptive methods, retrospective analysis, method of comparison. The results showed that the drugs containing the active substances of the angiotensin converting enzyme inhibitors class had had significant increases in quantitative and value sales, bringing substantial revenues to pharmacies. From the quantitative perspective, the best-selling products were those containing Enalaprilum, while in terms of value, the best-selling medicines were those containing Perindoprilum. We evidenced that spectacular sales were also achieved for products that have Lisinoprilum, respectively Captoprilum, as active substances. The largest quantities were marketed for the Captopril Terapia® product and the highest earnings were recorded for the Prestarium® medicine. This paper approaches an interesting and topical issue, which can be helpful to professionals (pharmacists, doctors) and other categories, such as economists, statisticians, representatives of companies manufacturing medicines, as well as to hypertensive patients, as it could be used to warn population regarding the incidence of cardiovascular diseases, and, at the same time, trace sales trends in order to accomplish profitable business plans.

Wild-type and mutated IDH1/2 enzymes and therapy responses.

PubMed

Molenaar, Remco J; Maciejewski, Jaroslaw P; Wilmink, Johanna W; van Noorden, Cornelis J F

2018-04-01

Isocitrate dehydrogenase 1 and 2 (IDH1/2) are key enzymes in cellular metabolism, epigenetic regulation, redox states, and DNA repair. IDH1/2 mutations are causal in the development and/or progression of various types of cancer due to supraphysiological production of D-2-hydroxyglutarate. In various tumor types, IDH1/2-mutated cancers predict for improved responses to treatment with irradiation or chemotherapy. The present review discusses the molecular basis of the sensitivity of IDH1/2-mutated cancers with respect to the function of mutated IDH1/2 in cellular processes and their interactions with novel IDH1/2-mutant inhibitors. Finally, lessons learned from IDH1/2 mutations for future clinical applications in IDH1/2 wild-type cancers are discussed.

Joseph Rudinger memorial lecture: Unexpected functions of angiotensin converting enzyme, beyond its enzymatic activity.

PubMed

Martinez, Jean

2017-10-01

Angiotensin converting enzyme (ACE) is a well-known enzyme, largely studied for its action on hypertension, as it produces angiotensin II from angiotensin I. This paper describes two original behaviours of ACE. We showed that ACE could hydrolyse gastrin, a neuropeptide from the gastrointestinal tract, releasing the C-terminal amidated dipeptide H-Asp-Phe-NH 2 . This dipeptide is believed to be involved in the gastrin-induced acid secretion in the stomach. This hypothetic mechanism of action of gastrin resulted in a strategy to rationally design gastrin receptor antagonists. Beyond, we showed that the brain renin angiotensin system (RAS) could be activated by a new characterized peptide named acein, resulting in stimulation of dopamine release within the striatum. This new and original 'receptor-like' activity for brain membrane-bound ACE is quite significant taking into account the role of dopamine in the brain, particularly in neurodegenerative diseases. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Influence of gas-liquid two-phase flow on angiotensin-I converting enzyme inhibitory peptides separation by ultra-filtration.

PubMed

Charoenphun, Narin; Youravong, Wirote

2017-01-01

Membrane fouling is a major problem in ultra-filtration systems and two-phase flow is a promising technique for permeate flux enhancement. The objective of this research was to study the use of an ultra-filtration (UF) system to enrich angiotensin-I converting enzyme (ACE) inhibitory peptides from tilapia protein hydrolysate. To select the most appropriate membrane and operating condition, the effects of membrane molecular weight cut-off (MWCO), transmembrane pressure (TMP) and cross-flow velocity (CFV) on permeate flux and ACE inhibitory peptide separation were studied. Additionally, the gas-liquid two-phase flow technique was applied to investigate its effect on the process capability. The results showed that the highest ACE inhibitory activity was obtained from permeate of the 1 kDa membrane. In terms of TMP and CFV, the permeate flux tended to increase with TMP and CFV. The use of gas-liquid two-phase flow as indicated by shear stress number could reduce membrane fouling and increase the permeate flux up to 42%, depending on shear stress number. Moreover, the use of a shear stress number of 0.039 led to an augmentation in ACE inhibitory activity of permeates. Operating conditions using a shear stress number of 0.039 were recommended for enrichment of ACE inhibitory peptides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

[Prospective observational study of angiotensin converting enzyme inhibitors-induced hyperkalemia in hospitalized patients with chronic renal failure].

PubMed

Ben Mahmoud, Lobna; Ghozzi, Hanene; Kammoun, Khawla; Hakim, Ahmed; Kharrat, Mahmoud; Ben Hmida, Mohamed; Jarraya, Faical; Sahnoun, Zouheir; Zeghal, Khaled; Hachicha, Jamil

2013-04-01

To study the incidence and risk factors of angiotensin converting enzyme inhibitors-induced hyperkalemia in hospitalized patients with hypertension and preexisting chronic renal failure. Two-months prospective observational study was used including all hospitalized patients older than 18 years with a history of hypertension, non-dialyzed chronic renal failure and who had angiotensin converting enzyme prescription at the time of the admission. Hyperkalemia greater than or equal to 5 mmol/L was detected in these patients. The studied variables were demographic, clinical, biological and therapeutic. Eight patients, among 27 included, had a hyperkalemia (2963%). They were 73±15 years old. Factors that predispose to hyperkalemia were present in all patients. Hyperkalemia was associated in six cases with decompensation of renal function. The age was associated with hyperkalaemia in patients treated with angiotensin converting enzyme inhibitors (RC=1.21; IC95 1,11-1,46; P=0,021). Diabetes is a possible risk factor (OR=59 021 et, 95 0.93 to 2410, P=0.053). Compared with patients who did not develop hyperkalemia, the occurrence of hyperkalemia in patients included was associated with a longer duration of hospitalization (OR=130, 95 112 to 160, P=0. 022). The prescription of angiotensin converting enzyme inhibitors in the elderly with chronic renal failure and diabetes requires careful monitoring of serum potassium. Copyright © 2012 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Angiotensin I-converting enzyme-inhibitory activity of the Norwegian autochthonous cheeses Gamalost and Norvegia after in vitro human gastrointestinal digestion.

PubMed

Qureshi, T M; Vegarud, G E; Abrahamsen, R K; Skeie, S

2013-02-01

The angiotensin I-converting enzyme (ACE) inhibitory activity of Gamalost cheese, its pH 4.6-soluble fraction, and Norvegia cheese was monitored before and after digestion with human gastric and duodenal juices. Both Gamalost and Norvegia cheeses showed an increased ACE-inhibitory activity during gastrointestinal digestion. However, only Norvegia showed pronounced increased activity after duodenal digestion. More peptides were detected in digested Gamalost compared with digested Norvegia. Most of the peptides in Gamalost were derived from β-casein (CN), some originated from α(s1)-CN, and only a very few originated from α(s2)-CN and κ-CN. In general, the number of peptides increased during gastrointestinal digestion, whereas some peptides were further degraded and disappeared; however, surprisingly, a few peptides remained stable. The aromatic amino acids, such as Tyr, Phe, and Trp; the positively charged amino acids (Arg and Lys); and Leu increased after simulated gastrointestinal digestion of Gamalost and Norvegia. After in vitro gastrointestinal digestion, both Gamalost and Norvegia showed high ACE-inhibitory activity, which may contribute in lowering of mild hypertension. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Investigation of lactic acid bacterial strains for meat fermentation and the product's antioxidant and angiotensin-I-converting-enzyme inhibitory activities.

PubMed

Takeda, Shiro; Matsufuji, Hisashi; Nakade, Koji; Takenoyama, Shin-Ichi; Ahhmed, Abdulatef; Sakata, Ryoichi; Kawahara, Satoshi; Muguruma, Michio

2017-03-01

In the lactic acid bacteria (LAB) strains screened from our LAB collection, Lactobacillus (L.) sakei strain no. 23 and L. curvatus strain no. 28 degraded meat protein and tolerated salt and nitrite in vitro. Fermented sausages inoculated strains no. 23 and no. 28 showed not only favorable increases in viable LAB counts and reduced pH, but also the degradation of meat protein. The sausages fermented with these strains showed significantly higher antioxidant activity than those without LAB or fermented by each LAB type strain. Angiotensin-I-converting-enzyme (ACE) inhibitory activity was also significantly higher in the sausages fermented with strain no. 23 than in those fermented with the type strain. Higher ACE inhibitory activity was also observed in the sausages fermented with strain no. 28, but did not differ significantly from those with the type strain. An analysis of the proteolysis and degradation products formed by each LAB in sausages suggested that those bioactivities yielded fermentation products such as peptides. Therefore, LAB starters that can adequately ferment meat, such as strains no. 23 and no. 28, should contribute to the production of bioactive compounds in meat products. © 2016 Japanese Society of Animal Science.

Lack of any association between insertion/deletion (I/D) polymorphisms in the angiotensin-converting enzyme gene and digestive system cancer risk: a meta-analysis.

PubMed

Liu, Jin-Fei; Xie, Hao-Jun; Cheng, Tian-Ming

2013-01-01

To investigate the association between the gene polymorphisms of angiotensin-converting enzyme (ACE) and digestive system cancer risk. A search was performed in Pubmed, Medline, ISI Web of Science and Chinese Biomedical (CBM) databases, covering all studies until Sep 1st, 2013. Statistical analysis was performed by using Revman5.2 and STATA 12.0. A total of 15 case-control studies comprising 2,390 digestive system cancer patients and 9,706 controls were identified. No significant association was found between the I/D polymorphism and digestive cancer risk (OR =0.93, 95%CI = (0.75, 1.16), P =0.53 for DD+DI vs. II). In the subgroup analysis by ethnicity and cancer type, no significant associations were found for the comparison of DD+DI vs. II. Results from other comparative genetic models also indicated a lack of associations between this polymorphism and digestive system cancer risks. This meta-analysis suggested that the ACE D/I polymorphism might not contribute to the risk of digestive system cancer.

[From gene to disease; primary hyperoxaluria type I caused by mutations in the AGXT gene].

PubMed

van Woerden, C S; Groothof, J W; Wanders, R J A; Waterham, H R; Wijburg, F R

2006-07-29

Primary hyperoxaluria type I (PH1) is a congenital defect in glyoxylate metabolism caused by a deficiency in the liver-specific peroxisomal enzyme known as alanine glyoxylate aminotransferase (AGT). The deficiency is due to mutations in the AGXT gene, located on chromosome 2q37.3, and results in the conversion of glyoxylate to oxalate. The crystallisation of oxalate with calcium results in symptoms varying from a solitary kidney stone to end-stage renal disease with systemic oxalosis. The diagnosis is based on increased oxalate and glycolate excretion in the urine, reduced AGT activity in liver tissue, and confirmed mutations in the AGXT gene. Over 50 disease-causing mutations have been identified in PH1, which are associated with a wide range of effects on the AGT enzyme. Homozygous Gly170Arg or Phei52Ile mutations are associated with a reduction in urinary oxalate excretion upon pyridoxine administration and long-term preservation of renal function when treatment is initiated in a timely manner. Homozygous 33insC and Gly82Arg mutations result in a much poorer prognosis. Mutational analysis of the AGXT gene in PH1 patients can be a useful tool for establishing the diagnosis and choosing an appropriate therapeutic strategy.

Role of Renin-Angiotensin-converting Enzyme Level and ACE Gene Polymorphism in Patients with Nonalcoholic Fatty Liver Disease.

PubMed

Tekatas, Demet D; Bahcecioglu, Ibrahim H; Ispiroglu, Murat; Sahin, Abdurrahman; Ilhan, Necip; Yalniz, Mehmet; Demirel, Ulvi

2016-01-01

In this study, we aimed to investigate the histological and clinical effect of angiotensin-converting enzyme (ACE) and ACE gene polymorphism in nonalcoholic fatty liver disease (NAFLD) and their roles in the progression of the disease. Liver function tests, body mass index, waist circumference, lipid parameters, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), homeostasis model assessment-IR (HOMA-IR), ACE, and ACE gene polymorphism were evaluated in the NAFLD group and control group. The study group was evaluated by dividing the group into four subgroups by ACE gene polymorphism (D/D homozygous, I/I homozygous, D/I heterozygous, I/D heterozygous). Liver biopsies were evaluated according to Brunt Classification. A total of 31 patients who were diagnosed with NAFLD and 40 healthy individuals were included in the study. The ACE level was found to be 11.69 ± 1.99 in the NAFLD group and 11.52 ± 1.72 in the control group (p = 0.70). There was a negative correlation between ACE levels and HOMA-IR levels (p = 0.008, r= -0.512). Biochemical parameters were not different among ACE gene polimorphism subgroups, except FBG (between D/D, I/D and D/I, I/D; p = 0.02). When the ACE levels were compared in terms of grade and stage, no significant difference was found (for stage and grade p = 0.68). The ACE gene polymorphism subgroups did not differ by histopathologic findings; grade and stage (for grade p = 0.42, for stage p = 0.92). In this study, we could not find a correlation of ACE and ACE gene polymorphism with metabolic risk factors and the disease severity in NAFLD. Tekatas DD, Bahcecioglu IH, Ispiroglu M, Sahin A, Ilhan N, Yalniz M, Demirel U. Role of Renin-Angiotensin-converting Enzyme Level and ACE Gene Polymorphism in Patients with Nonalcoholic Fatty Liver Disease. Euroasian J Hepato-Gastroenterol 2016;6(2):137-142.

Angiotensin converting enzyme DD genotype is associated with hypertensive crisis.

PubMed

Sunder-Plassmann, Gere; Kittler, Harald; Eberle, Corinna; Hirschl, Michael M; Woisetschläger, Christian; Derhaschnig, Ulla; Laggner, Anton N; Hörl, Walter H; Födinger, Manuela

2002-10-01

The genetic background of hypertensive crisis is unknown. We examined the association of polymorphisms in genes involved in the renin-angiotensin-aldosterone-system with hypertensive crisis. Population-based case-control study. Emergency department at a tertiary care university hospital. A total of 182 patients with essential hypertension who were admitted to an emergency department for treatment of hypertensive crisis and 182 age- and sex-matched healthy individuals. None. Analysis of polymorphisms in genes coding for angiotensinogen (AJT 704T-->C), angiotensin II receptor 1 (AGTR1 1166A-->C), renin (REN 2646G-->A), renin-binding protein (RENBP 61T-->C), alpha-adducin (ADD1 1378G-->T), beta-2-adrenergic receptor (ADRB2 46A-->G, 79C-->G), and angiotensin I converting enzyme (ACE I/D) was performed by polymerase chain reaction and restriction fragment length polymorphism analysis. MAIN RESULTS Among patients, the ACE I/D polymorphism showed a deviation from Hardy-Weinberg equilibrium (p =.01). In controls, all polymorphisms were in the Hardy-Weinberg equilibrium. The frequency of the DD genotype was increased in patients (n = 70, 38.5%) vs. controls (n = 51; 28.0%;p =.03; odds ratio, 1.61; 95% confidence interval, 1.03-2.50), which was due to the DD genotype in 40 male patients (44%) vs. 23 in male controls (25.3%;p =.004; odds ratio, 3.48; 95% confidence interval, 1.47-8.30). There were no differences in genotype distributions among other polymorphisms. We demonstrate a possible association of the DD genotype with hypertensive crisis in men.

A novel lactone-forming carboxylesterase: molecular identification of a tuliposide A-converting enzyme in tulip.

PubMed

Nomura, Taiji; Ogita, Shinjiro; Kato, Yasuo

2012-06-01

Tuliposides, the glucose esters of 4-hydroxy-2-methylenebutanoate and 3,4-dihydroxy-2-methylenebutanoate, are major secondary metabolites in tulip (Tulipa gesneriana). Their lactonized aglycons, tulipalins, function as defensive chemicals due to their biological activities. We recently found that tuliposide-converting enzyme (TCE) purified from tulip bulbs catalyzed the conversion of tuliposides to tulipalins, but the possibility of the presence of several TCE isozymes was raised: TCE in tissues other than bulbs is different from bulb TCE. Here, to prove this hypothesis, TCE was purified from petals, which have the second highest TCE activity after bulbs. The purified enzyme, like the bulb enzyme, preferentially accepted tuliposides as substrates, with 6-tuliposide A the best substrate, which allowed naming the enzyme tuliposide A-converting enzyme (TCEA), but specific activity and molecular mass differed between the petal and bulb enzymes. After peptide sequencing, a novel cDNA (TgTCEA) encoding petal TCEA was isolated, and the functional characterization of the recombinant enzyme verified that TgTCEA catalyzes the conversion of 6-tuliposide A to tulipalin A. TgTCEA was transcribed in all tulip tissues but not in bulbs, indicating the presence of a bulb-specific TgTCEA, as suggested by the distinct enzymatic characters between the petal and bulb enzymes. Plastidial localization of TgTCEA enzyme was revealed, which allowed proposing a cytological mechanism of TgTCE-mediated tulipalin formation in the tulip defensive strategy. Site-directed mutagenesis of TgTCEA suggested that the oxyanion hole and catalytic triad characteristic of typical carboxylesterases are essential for the catalytic process of TgTCEA enzyme. To our knowledge, TgTCEA is the first identified member of the lactone-forming carboxylesterases, specifically catalyzing intramolecular transesterification.

Role of genetic mutations in folate-related enzyme genes on Male Infertility

PubMed Central

Liu, Kang; Zhao, Ruizhe; Shen, Min; Ye, Jiaxin; Li, Xiao; Huang, Yuan; Hua, Lixin; Wang, Zengjun; Li, Jie

2015-01-01

Several studies showed that the genetic mutations in the folate-related enzyme genes might be associated with male infertility; however, the results were still inconsistent. We performed a meta-analysis with trial sequential analysis to investigate the associations between the MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G mutations and the MTHFR haplotype with the risk of male infertility. Overall, a total of 37 studies were selected. Our meta-analysis showed that the MTHFR C677T mutation was a risk factor for male infertility in both azoospermia and oligoasthenoteratozoospermia patients, especially in Asian population. Men carrying the MTHFR TC haplotype were most liable to suffer infertility while those with CC haplotype had lowest risk. On the other hand, the MTHFR A1298C mutation was not related to male infertility. MTR A2756G and MTRR A66G were potential candidates in the pathogenesis of male infertility, but more case-control studies were required to avoid false-positive outcomes. All of these results were confirmed by the trial sequential analysis. Finally, our meta-analysis with trial sequential analysis proved that the genetic mutations in the folate-related enzyme genes played a significant role in male infertility. PMID:26549413

Energy-converting [NiFe] hydrogenases from archaea and extremophiles: ancestors of complex I.

PubMed

Hedderich, Reiner

2004-02-01

[NiFe] hydrogenases are well-characterized enzymes that have a key function in the H2 metabolism of various microorganisms. In the recent years a subfamily of [NiFe] hydrogenases with unique properties has been identified. The members of this family form multisubunit membrane-bound enzyme complexes composed of at least four hydrophilic and two integral membrane proteins. These six conserved subunits, which built the core of these hydrogenases, have closely related counterparts in energy-conserving NADH:quinone oxidoreductases (complex I). However, the reaction catalyzed by these hydrogenases differs significantly from the reaction catalyzed by complex I. For some of these hydrogenases the physiological role is to catalyze the reduction of H+ with electrons derived from reduced ferredoxins or poly-ferredoxins. This exergonic reaction is coupled to energy conservation by means of electron-transport phosphorylation. Other members of this hydrogenase family mainly function to provide the cell with reduced ferredoxin with H2 as electron donor in a reaction driven by reverse electron transport. As complex I these hydrogenases function as ion pumps and have therefore been designated as energy-converting [NiFe] hydrogenases.

Mapping Interactions between Myosin Relay and Converter Domains That Power Muscle Function*

PubMed Central

Kronert, William A.; Melkani, Girish C.; Melkani, Anju; Bernstein, Sanford I.

2014-01-01

Intramolecular communication within myosin is essential for its function as motor, but the specific amino acid residue interactions required are unexplored within muscle cells. Using Drosophila melanogaster skeletal muscle myosin, we performed a novel in vivo molecular suppression analysis to define the importance of three relay loop amino acid residues (Ile508, Asn509, and Asp511) in communicating with converter domain residue Arg759. We found that the N509K relay mutation suppressed defects in myosin ATPase, in vitro motility, myofibril stability, and muscle function associated with the R759E converter mutation. Through molecular modeling, we define a mechanism for this interaction and suggest why the I508K and D511K relay mutations fail to suppress R759E. Interestingly, I508K disabled motor function and myofibril assembly, suggesting that productive relay-converter interaction is essential for both processes. We conclude that the putative relay-converter interaction mediated by myosin residues 509 and 759 is critical for the biochemical and biophysical function of skeletal muscle myosin and the normal ultrastructural and mechanical properties of muscle. PMID:24627474

The angiotensin-converting-enzyme insertion/deletion polymorphism is not related to venous thrombosis.

PubMed

Köppel, Herwig; Renner, Wilfried; Gugl, Alexander; Cichocki, Lisa; Gasser, Robert; Wascher, Thomas C; Pilger, Ernst

2004-01-01

The insertion/deletion (I/D) polymorphism of the gene for angiotensin-converting-enzyme (ACE) is associated with ACE plasma levels and activity. Conflicting results have been reported about the relevance of this polymorphism for venous thrombosis. The aim of the present study was to analyze the role of this polymorphism for deep venous thrombosis. The study was designed as a case-control study, including 330 patients with documented deep venous thrombosis and 354 controls. ACE genotype was determined by size-analysis of polymerase chain reaction products. Results showed that, ACE genotype frequencies were similar between patients (II: 24.8%; ID: 43.3%; DD: 31.8%) and controls (II: 22.9%; ID: 50.6%; DD: 26.6%, P = 0.15). The adjusted odds ratio of carriers of the DD geno-type for venous thrombosis was 1.24 (95% confidence interval 0.90-1.80). The polymorphism was furthermore not associated with age at first thromboembolic event or the occurrence of pulmonary embolism. From these results, we can conclude that the ACE I/D polymorphism is not a significant risk factor for deep venous thrombosis.

Marketing research on the angiotensin-converting enzyme inhibitors antihypertensive medicines

PubMed Central

BOBOIA, ANAMARIA; GRIGORESCU, MARIUS RAREŞ; TURCU - ŞTIOLICĂ, ADINA

2017-01-01

Background and aims The research aimed at investigating sales trends of angiotensin-converting enzyme inhibitors antihypertensive medicines, both in terms of quantity and value, in ten community pharmacies, for a period of three years. The research on the antihypertensive medicines consumption is important for highlighting the ever increasing impact of hypertension among the population. Methods The methods used in this research were the following: marketing research, method of sampling, descriptive methods, retrospective analysis, method of comparison. Results The results showed that the drugs containing the active substances of the angiotensin converting enzyme inhibitors class had had significant increases in quantitative and value sales, bringing substantial revenues to pharmacies. From the quantitative perspective, the best-selling products were those containing Enalaprilum, while in terms of value, the best-selling medicines were those containing Perindoprilum. We evidenced that spectacular sales were also achieved for products that have Lisinoprilum, respectively Captoprilum, as active substances. The largest quantities were marketed for the Captopril Terapia® product and the highest earnings were recorded for the Prestarium® medicine. Conclusion This paper approaches an interesting and topical issue, which can be helpful to professionals (pharmacists, doctors) and other categories, such as economists, statisticians, representatives of companies manufacturing medicines, as well as to hypertensive patients, as it could be used to warn population regarding the incidence of cardiovascular diseases, and, at the same time, trace sales trends in order to accomplish profitable business plans. PMID:28246502

Production of the angiotensin I converting enzyme inhibitory peptides and isolation of four novel peptides from jellyfish (Rhopilema esculentum) protein hydrolysate.

PubMed

Liu, Xin; Zhang, Miansong; Shi, Yaping; Qiao, Ruojin; Tang, Wei; Sun, Zhenliang

2016-07-01

Angiotensin I converting enzyme (ACE) plays an important role in regulating blood pressure in the human body. ACE inhibitory peptides derived from food proteins could exert antihypertensive effects without side effects. Jellyfish (Rhopilema esculentum) is an important fishery resource suitable for production of ACE inhibitory peptides. The objective of this study was to optimize the hydrolysis conditions for production of protein hydrolysate from R. esculentum (RPH) with ACE inhibitory activity, and to isolate and identify the ACE inhibitory peptides from RPH. Rhopilema esculentum protein was hydrolyzed with Compound proteinase AQ to produce protein hydrolysate with ACE inhibitory activity, and the hydrolysis conditions were optimized using response surface methodology. The optimum parameters for producing peptides with the highest ACE inhibitory activity were as follows: hydrolysis time 3.90 h, hydrolysis temperature 58 °C, enzyme:substrate ratio 2.8% and pH 7.60. Under these conditions, the ACE inhibitory rate reached 32.21%. In addition, four novel ACE inhibitory peptides were isolated, and their amino acids sequences were identified as Val-Gly-Pro-Tyr, Phe-Thr-Tyr-Val-Pro-Gly, Phe-Thr-Tyr-Val-Pro-Gly-Ala and Phe-Gln-Ala-Val-Trp-Ala-Gly, respectively. The IC50 value of the purified peptides for ACE inhibitory activity was 8.40, 23.42, 21.15 and 19.11 µmol L(-1) . These results indicate that the protein hydrolysate prepared from R. esculentum might be a commercial competitive source of ACE inhibitory ingredients to be used in functional foods. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Characterization of PgPepO, a bacterial homologue of endothelin-converting enzyme-1.

PubMed

Carson, Julie A; Ansai, Toshihiro; Awano, Shuji; Yu, Weixian; Takehara, Tadamichi; Turner, Anthony J

2002-08-01

PgPepO is a homologue of endothelin-converting enzyme-1 (ECE-1), with which it shares 31% identity. PgPepO was isolated from the periodontal pathogen Porphyromonas gingivalis. Recent studies have suggested a link between periodontal and cardiovascular disease, and several groups have suggested that bacterial and viral infections may contribute to the latter. P. gingivalis possesses the ability to invade, and multiply within, aortic endothelial cells and has been localized to atherosclerotic plaques. PgPepO was expressed and purified to homogeneity and we have begun detailed functional analysis, in terms of substrate preference and inhibitor specificity, in order to provide active-site comparisons with other members of the neprilysin (NEP)/ECE family. PgPepO possesses similar substrate specificity to ECE-1 and has been shown to cleave big endothelin-1 (big ET-1), big ET-2 and big ET-3, converting the substrates into their respective mature endothelin peptides. Substance P, angiotensin I, angiotensin II and neurotensin are all cleaved at multiple sites by PgPepO and the kinetics of these reactions have been compared. The potent vasoconstrictor urotensin II is not hydrolysed by PgPepO. Cleavage of bradykinin by PgPepO occurs at the Pro(7)-Phe(8) bond and is inhibited by the NEP and ECE-1 inhibitor phosphoramidon in a pH-dependent fashion (IC(50) =10 microM at pH 7.0) but not by thiorphan, an NEP-specific inhibitor. PgPepO activity is completely inhibited by EDTA. Characterization of this enzyme is important in elucidating possible links between periodontal pathogens and cardiovascular disorders such as atherosclerosis, and provides an opportunity to gain structural information on a bacterial protein with striking similarity to human ECE-1.

Trade-offs with stability modulate innate and mutationally acquired drug-resistance in bacterial dihydrofolate reductase enzymes.

PubMed

Matange, Nishad; Bodkhe, Swapnil; Patel, Maitri; Shah, Pooja

2018-06-05

Structural stability is a major constraint on the evolution of protein sequences. However, under strong directional selection, mutations that confer novel phenotypes but compromise structural stability of proteins may be permissible. During the evolution of antibiotic resistance, mutations that confer drug resistance often have pleiotropic effects on the structure and function of antibiotic-target proteins, usually essential metabolic enzymes. In this study, we show that trimethoprim-resistant alleles of dihydrofolate reductase from Escherichia coli (EcDHFR) harbouring the Trp30Gly, Trp30Arg or Trp30Cys mutations are significantly less stable than the wild type making them prone to aggregation and proteolysis. This destabilization is associated with lower expression level resulting in a fitness cost and negative epistasis with other TMP-resistant mutations in EcDHFR. Using structure-based mutational analysis we show that perturbation of critical stabilizing hydrophobic interactions in wild type EcDHFR enzyme explains the phenotypes of Trp30 mutants. Surprisingly, though crucial for the stability of EcDHFR, significant sequence variation is found at this site among bacterial DHFRs. Mutational and computational analyses in EcDHFR as well as in DHFR enzymes from Staphylococcus aureus and Mycobacterium tuberculosis demonstrate that natural variation at this site and its interacting hydrophobic residues, modulates TMP-resistance in other bacterial DHFRs as well, and may explain the different susceptibilities of bacterial pathogens to trimethoprim. Our study demonstrates that trade-offs between structural stability and function can influence innate drug resistance as well as the potential for mutationally acquired drug resistance of an enzyme. ©2018 The Author(s).

Molecular identification of tuliposide B-converting enzyme: a lactone-forming carboxylesterase from the pollen of tulip.

PubMed

Nomura, Taiji; Murase, Tatsunori; Ogita, Shinjiro; Kato, Yasuo

2015-07-01

6-Tuliposides A (PosA) and B (PosB), which are the major secondary metabolites in tulip (Tulipa gesneriana), are enzymatically converted to the antimicrobial lactonized aglycons, tulipalins A (PaA) and B (PaB), respectively. We recently identified a PosA-converting enzyme (TCEA) as the first reported member of the lactone-forming carboxylesterases. Herein, we describe the identification of another lactone-forming carboxylesterase, PosB-converting enzyme (TCEB), which preferentially reacts with PosB to give PaB. This enzyme was isolated from tulip pollen, which showed high PosB-converting activity. Purified TCEB exhibited greater activity towards PosB than PosA, which was contrary to that of the TCEA. Novel cDNA (TgTCEB1) encoding the TCEB was isolated from tulip pollen. TgTCEB1 belonged to the carboxylesterase family and was approximately 50% identical to the TgTCEA polypeptides. Functional characterization of the recombinant enzyme verified that TgTCEB1 catalyzed the conversion of PosB to PaB with an activity comparable with the native TCEB. RT-qPCR analysis of each part of plant revealed that TgTCEB1 transcripts were limited almost exclusively to the pollen. Furthermore, the immunostaining of the anther cross-section using anti-TgTCEB1 polyclonal antibody verified that TgTCEB1 was specifically expressed in the pollen grains, but not in the anther cells. N-terminal transit peptide of TgTCEB1 was shown to function as plastid-targeted signal. Taken together, these results indicate that mature TgTCEB1 is specifically localized in plastids of pollen grains. Interestingly, PosB, the substrate of TgTCEB1, accumulated on the pollen surface, but not in the intracellular spaces of pollen grains. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Lignocellulose-converting enzyme activity profiles correlate with molecular systematics and phylogeny grouping in the incoherent genus Phlebia (Polyporales, Basidiomycota).

PubMed

Kuuskeri, Jaana; Mäkelä, Miia R; Isotalo, Jarkko; Oksanen, Ilona; Lundell, Taina

2015-10-19

The fungal genus Phlebia consists of a number of species that are significant in wood decay. Biotechnological potential of a few species for enzyme production and degradation of lignin and pollutants has been previously studied, when most of the species of this genus are unknown. Therefore, we carried out a wider study on biochemistry and systematics of Phlebia species. Isolates belonging to the genus Phlebia were subjected to four-gene sequence analysis in order to clarify their phylogenetic placement at species level and evolutionary relationships of the genus among phlebioid Polyporales. rRNA-encoding (5.8S, partial LSU) and two protein-encoding gene (gapdh, rpb2) sequences were adopted for the evolutionary analysis, and ITS sequences (ITS1+5.8S+ITS2) were aligned for in-depth species-level phylogeny. The 49 fungal isolates were cultivated on semi-solid milled spruce wood medium for 21 days in order to follow their production of extracellular lignocellulose-converting oxidoreductases and carbohydrate active enzymes. Four-gene phylogenetic analysis confirmed the polyphyletic nature of the genus Phlebia. Ten species-level subgroups were formed, and their lignocellulose-converting enzyme activity profiles coincided with the phylogenetic grouping. The highest enzyme activities for lignin modification (manganese peroxidase activity) were obtained for Phlebia radiata group, which supports our previous studies on the enzymology and gene expression of this species on lignocellulosic substrates. Our study implies that there is a species-level connection of molecular systematics (genotype) to the efficiency in production of both lignocellulose-converting carbohydrate active enzymes and oxidoreductases (enzyme phenotype) on spruce wood. Thus, we may propose a similar phylogrouping approach for prediction of lignocellulose-converting enzyme phenotypes in new fungal species or genetically and biochemically less-studied isolates of the wood-decay Polyporales.

Mutating the converter-relay interface of Drosophila myosin perturbs ATPase activity, actin motility, myofibril stability and flight ability.

PubMed

Kronert, William A; Melkani, Girish C; Melkani, Anju; Bernstein, Sanford I

2010-05-21

We used an integrative approach to probe the significance of the interaction between the relay loop and converter domain of the myosin molecular motor from Drosophila melanogaster indirect flight muscle. During the myosin mechanochemical cycle, ATP-induced twisting of the relay loop is hypothesized to reposition the converter, resulting in cocking of the contiguous lever arm into the pre-power stroke configuration. The subsequent movement of the lever arm through its power stroke generates muscle contraction by causing myosin heads to pull on actin filaments. We generated a transgenic line expressing myosin with a mutation in the converter domain (R759E) at a site of relay loop interaction. Molecular modeling suggests that the interface between the relay loop and converter domain of R759E myosin would be significantly disrupted during the mechanochemical cycle. The mutation depressed calcium as well as basal and actin-activated MgATPase (V(max)) by approximately 60% compared to wild-type myosin, but there is no change in apparent actin affinity (K(m)). While ATP or AMP-PNP (adenylyl-imidodiphosphate) binding to wild-type myosin subfragment-1 enhanced tryptophan fluorescence by approximately 15% or approximately 8%, respectively, enhancement does not occur in the mutant. This suggests that the mutation reduces lever arm movement. The mutation decreases in vitro motility of actin filaments by approximately 35%. Mutant pupal indirect flight muscles display normal myofibril assembly, myofibril shape, and double-hexagonal arrangement of thick and thin filaments. Two-day-old fibers have occasional "cracking" of the crystal-like array of myofilaments. Fibers from 1-week-old adults show more severe cracking and frayed myofibrils with some disruption of the myofilament lattice. Flight ability is reduced in 2-day-old flies compared to wild-type controls, with no upward mobility but some horizontal flight. In 1-week-old adults, flight capability is lost. Thus, altered myosin

Bioavailability of angiotensin I-converting enzyme (ACE) inhibitory peptides derived from Virgibacillus halodenitrificans SK1-3-7 proteinases hydrolyzed tilapia muscle proteins.

PubMed

Toopcham, Tidarat; Mes, Jurriaan J; Wichers, Harry J; Roytrakul, Sittiruk; Yongsawatdigul, Jirawat

2017-04-01

The angiotensin I-converting enzyme (ACE) inhibitory activity of protein hydrolysates from tilapia muscle fractions, namely mince (M), washed mince (WM), and sarcoplasmic protein (SP), were investigated. Each fraction was hydrolyzed by Virgibacillus halodenitrificans SK1-3-7 proteinases for up to 24h. After 8h of hydrolysis, the M hydrolysate (48% degree of hydrolysis (DH)) showed the highest ACE inhibitory activity, with an IC 50 value of 0.54mg/ml, while the SP hydrolysate exhibited the lowest DH and ACE inhibition. In vitro gastrointestinal digestion reduced the ACE inhibitory activity of the M hydrolysate but enhanced its transport across Caco-2 cell monolayers. The transported peptides were found to contain 3-4 amino acid residues showing strong ACE inhibition. The novel ACE inhibitory peptide with the highest inhibition was found to be MCS, with an IC 50 value of 0.29μM. Therefore, tilapia mince hydrolyzed by V. halodenitrificans proteinases contained ACE inhibitory peptides that are potentially bioavailable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduction of dopaminergic degeneration and oxidative stress by inhibition of angiotensin converting enzyme in a MPTP model of parkinsonism.

PubMed

Muñoz, Ana; Rey, Pablo; Guerra, Maria J; Mendez-Alvarez, Estefania; Soto-Otero, Ramon; Labandeira-Garcia, Jose L

2006-07-01

There is growing evidence indicating that oxidative stress is a key contributor to the pathogenesis and progression of Parkinson's disease. The brain, and particularly the basal ganglia, possesses a local rennin-angiotensin system. Angiotensin activates NAD(P)H-dependent oxidases, which are a major intracellular source of superoxide, and angiotensin converting enzyme inhibitors (ACEIs) have shown antioxidant properties. We treated mice with MPTP and the ACEI captopril to study the possible neuroprotective and antioxidant effects of the latter on the dopaminergic system. Pre-treatment with captopril induced a significant reduction in the MPTP-induced loss of dopaminergic neurons in the substantia nigra and a significant reduction in the loss of dopaminergic terminals in the striatum. Furthermore, captopril reduced the MPTP-induced increase in the levels of major oxidative stress indicators (i.e. lipid peroxidation and protein oxidation) in the ventral midbrain and the striatum. Captopril did not reduce striatal MPP(+) levels, MAO-B activity or dopamine transporter activity, which may reduce MPTP neurotoxicity. Our results suggest that angiotensin-converting enzyme inhibitors may be useful for treatment of Parkinson's disease, and that further investigation should focus on the neuroprotective capacity of these compounds.

TEM-induced gene mutations at enzyme loci in the mouse.

PubMed

Soares, E R

1979-01-01

Strain DBA/2J male mice were treated with triethylenemelamine (TEM) and subsequently mated to strain C57BL/6J females. Tissues from F1 progeny produced in these crosses were then examined using starch gel electrophoresis for the presence of presumed induced mutations at a series of 11 specific enzyme loci. In the course of this study, four heritable mutations were identified at the following loci: Es-1, Ldh-1, Pgm-1, and Gpi-1. Of these four, the first two were apparently segregating in parental males and were not TEM-induced. Both of these are viable and fertile in the heterozygous and homozygous condition, and neither confers any readily apparent deleterious effect to the animal. The latter mutations (Pgm-1 and Gpi-1) are presumably induced. Although viable and fertile in the heterozygous state, we have not recovered any offsping homozygous for either of these two mutations.

Exploration of the molecular interactions between angiotensin-I-converting enzyme (ACE) and the inhibitory peptides derived from hazelnut (Corylus heterophylla Fisch.).

PubMed

Liu, Chunlei; Fang, Li; Min, Weihong; Liu, Jingsheng; Li, Hongmei

2018-04-15

The mechanism of action of food-derived angiotensin-I-converting enzyme (ACE) inhibitory peptides has not been completely elucidated. In the present study, ion-exchange chromatography, gel filtration chromatography, reverse phase-high performance liquid chromatography, and liquid chromatography-electrospray ionization-tandem mass (LC-ESI-MS/MS) were employed for purifying and identifying the ACE inhibitory peptides from hazelnut. To understand the mode of action of these peptides, ACE inhibition kinetics, in vitro and in vivo bioavailability assays, active site analysis, and interaction between the inhibitory peptides and ACE were investigated. The results identified novel ACE inhibitory peptides Ala-Val-Lys-Val-Leu (AVKVL), Tyr-Leu-Val-Arg (YLVR), and Thr-Leu-Val-Gly-Arg (TLVGR) with IC 50 values of 73.06, 15.42, and 249.3 μM, respectively. All peptides inhibited the ACE activity via a non-competitive mode. The binding free energies of AVKVL, YLVR, and TLVGR for ACE were -3.46, -6.48, and -7.37 kcal/mol, respectively. The strong inhibition of ACE by YLVR may be attributed to the formation of cation-pi interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Association of DD genotype of angiotensin-converting enzyme gene (I/D) polymorphism with hypertension among a North Indian population.

PubMed

Rana, Garima; Yadav, Suniti; Joshi, Shipra; Saraswathy, K N

2018-01-01

Hypertension, a major risk factor for cardiovascular diseases, is among the leading causes of morbidity and mortality worldwide. Genetic predisposition to the risk of developing hypertension due to angiotensin-converting enzyme (ACE) gene insertion(I)/deletion(D) polymorphism (through altered serum ACE activity) is well documented among various populations. The present study investigated the possible association between ACE (DD) genotype and hypertension using a nested case-control study design including 451 individuals (of either sex in the age group 30-65 years) from a rural North Indian population practicing agriculture and lacto-vegetarianism. Blood Pressure was classified using JNC-7 criterion. Age- and sex-matched individuals were selected from normotensive (N-122), pre-hypertensive (N-123), hypertensive not on medication (N-122), and hypertensive on medication (N-84) categories. Amplification of DNA and genotyping of PCR product was done using standard protocols. From the analysis, comparatively higher frequency of individuals with DD genotype in the hypertensive category was observed, indicating a possible relation between DD genotype and hypertension. The odds ratio analysis revealed 2.225 (1.13-4.37)-fold significant increased risk for hypertension among cases, validating the vulnerability of individuals with DD genotype towards hypertension. Thus, the present study highlights the increased risk for developing hypertension due to ACE DD genotype in the studied population.

Genetic variation of the angiotensin-converting enzyme gene: increased frequency of the insertion allele in Koreans.

PubMed

Hong, S H; Kang, B Y; Park, W H; Kim, J Q; Lee, C C

1997-01-01

In view of the clinical importance of angiotensin-converting enzyme (ACE) as a major marker for cardiovascular diseases, we investigated insertion/deletion (I/D) polymorphism of the ACE gene in Koreans. Genotype frequencies were examined by polymerase chain reaction in 171 patients with coronary artery disease (CAD) and 120 healthy subjects. Allele frequencies of ACE polymorphism in Koreans were not significantly different between patient and control groups. In addition, association between ACE genotypes and the number of stenosed coronary arteries was not detected. ACE genotypes in the CAD group were not associated with body mass index and plasma lipid levels. Thus, our results suggest that, at least in Koreans, I/D polymorphism of the gene is unlikely to be a useful marker for CAD subjects. However, the I allele frequency of Koreans (0.58) was higher than that of Caucasian populations (0.47) but lower than that of Samoan (0.91) and Yanomami (0.85) populations. Here, we discuss the clinical and ethnic importance of ACE polymorphism.

The effect of angiotensin-converting enzyme inhibition throughout a superovulation protocol in ewes.

PubMed

Pereira, Alécio Matos; de Souza Júnior, Antônio; Machado, Fernanda Brandão; Gonçalves, Gleisy Kelly Neves; Feitosa, Lauro César Soares; Reis, Adelina Martha; Santos, Robson Augusto Souza; Honorato-Sampaio, Kinulpe; Costa, Amilton Raposo

2015-12-01

Many studies identified new components of the renin–angiotensin system (RAS), such as Angiotensin-(1-7) [Ang-(1–7)] and Angiotensin-converting enzyme type 2 (ACE2), in mammalian ovaries.We previously showed Angiotensin-Converting Enzyme (ACE) inhibition, which increases the level of Ang-(1–7), stimulated ovarian estradiol output in ewe after estrous synchronization. Considering that Ang-(1–7) stimulates ovarian function and elevated estradiol before ovulation is associated with increased chance of achieving pregnancy, the present study investigated whether ACE inhibition throughout a superovulation protocol in ewe might improve ovulation outcome. At first, immunohistochemistry in ovaries of nonpregnant ewes revealed localization of Angiotensin II (Ang II), Ang-(1–7) and ACE2 in theca cells of antral follicles and in corpus luteum. Ang II and Ang-(1–7)were also detected in follicular fluid (FF) by Radioimmunoassay (RIA). Enalapril treatment throughout the superovulation protocol decreased 17β-estradiol (E2) output and raised progesterone:estradiol (P4:E2) ratio without a direct influence on ovulation and quality of embryos.

Utilization of peptide carrier system to improve intestinal absorption: targeting prolidase as a prodrug-converting enzyme

NASA Technical Reports Server (NTRS)

Bai, J. P.; Hu, M.; Subramanian, P.; Mosberg, H. I.; Amidon, G. L.

1992-01-01

The feasibility of targeting prolidase as a peptide prodrug-converting enzyme has been examined. The enzymatic hydrolysis by prolidase of substrates for the peptide transporter L-alpha-methyldopa-pro and several dipeptide analogues without an N-terminal alpha-amino group (phenylpropionylproline, phenylacetylproline, N-benzoylproline, and N-acetylproline) was investigated. The Michaelis-Menten parameters Km and Vmax for L-alpha-methyldopa-pro are 0.09 +/- 0.02 mM and 3.98 +/- 0.25 mumol/min/mg protein, respectively. However, no hydrolysis of the dipeptide analogues without an N-terminal alpha-amino group is observed, suggesting that an N-terminal alpha-amino group is required for prolidase activity. These results demonstrate that prolidase may serve as a prodrug-converting enzyme for the dipeptide-type prodrugs, utilizing the peptide carrier for transport of prodrugs into the mucosal cells and prolidase, a cytosolic enzyme, to release the drug. However, a free alpha-amino group appears to be necessary for prolidase hydrolysis.

Analysis of galactosemia-linked mutations of GALT enzyme using a computational biology approach.

PubMed

Facchiano, A; Marabotti, A

2010-02-01

We describe the prediction of the structural and functional effects of mutations on the enzyme galactose-1-phosphate uridyltransferase related to the genetic disease galactosemia, using a fully computational approach. One hundred and seven single-point mutants were simulated starting from the structural model of the enzyme obtained by homology modeling methods. Several bioinformatics programs were then applied to each resulting mutant protein to analyze the effect of the mutations. The mutations have a direct effect on the active site, or on the dimer assembly and stability, or on the monomer stability. We describe how mutations may exert their effect at a molecular level by altering H-bonds, salt bridges, secondary structure or surface features. The alteration of protein stability, at level of monomer and/or dimer, is the main effect observed. We found an agreement between our results and the functional experimental data available in literature for some mutants. The data and analyses for all the mutants are fully available in the web-accessible database hosted at http://bioinformatica.isa.cnr.it/GALT.

Exome sequencing identifies complex I NDUFV2 mutations as a novel cause of Leigh syndrome.

PubMed

Cameron, Jessie M; MacKay, Nevena; Feigenbaum, Annette; Tarnopolsky, Mark; Blaser, Susan; Robinson, Brian H; Schulze, Andreas

2015-09-01

Two siblings with hypertrophic cardiomyopathy and brain atrophy were diagnosed with Complex I deficiency based on low enzyme activity in muscle and high lactate/pyruvate ratio in fibroblasts. Whole exome sequencing results of fibroblast gDNA from one sibling was narrowed down to 190 SNPs or In/Dels in 185 candidate genes by selecting non-synonymous coding sequence base pair changes that were not present in the SNP database. Two compound heterozygous mutations were identified in both siblings in NDUFV2, encoding the 24 kDa subunit of Complex I. The intronic mutation (c.IVS2 + 1delGTAA) is disease causing and has been reported before. The other mutation is novel (c.669_670insG, p.Ser224Valfs*3) and predicted to cause a pathogenic frameshift in the protein. Subsequent investigation of 10 probands with complex I deficiency from different families revealed homozygosity for the intronic c.IVS2 + 1delGTAA mutation in a second, consanguineous family. In this family three of five siblings were affected. Interestingly, they presented with Leigh syndrome but no cardiac involvement. The same genotype had been reported previously in a two families but presenting with hypertrophic cardiomyopathy, trunk hypotonia and encephalopathy. We have identified NDUFV2 mutations in two families with Complex I deficiency, including a novel mutation. The diagnosis of Leigh syndrome expands the clinical phenotypes associated with the c.IVS2 + 1delGTAA mutation in this gene. Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Angiotensin-converting enzyme gene insertion/deletion polymorphism in Saudi patients with rheumatic heart disease

PubMed Central

Al-Harbi, Khalid M.; Almuzaini, Ibrahim S.; Morsy, Mohamed M.; Abdelaziz, Nada A.; Al-Balawi, Alia M.; Abdallah, Atiyeh M.

2015-01-01

Objectives: To investigate the association between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and rheumatic heart disease (RHD) in Saudi patients. Methods: A case-control study was conducted in Saudi RHD patients. Genomic DNA was isolated from 99 RHD patients attending the Pediatric Cardiology Clinic at the Maternity and Children Hospital, Al-Madinah, Saudi Arabia from March 2013 to June 2014, and from 145 age- and gender-matched controls. Patient clinical records were reviewed to report major and minor modified Jones’ criteria for diagnosis. The diagnosis was confirmed by echocardiography. The ACE I/D polymorphism was identified by polymerase chain reaction. Results: A significant difference in ACE D allele carriage (DD+ID) distribution between RHD cases and controls was identified (p=0.02, odds ratio = 3.6, 95% confidence interval: 1.2-10.8). The D allele carriage was significantly associated with development of mitral valve lesions alone (p=0.03). Conclusion: The ACE I/D polymorphism is associated with an increased risk of RHD in the Saudi population. Further studies are needed to confirm our findings and to understand the molecular mechanisms underlying this association. PMID:25719581

Characterization of an MPS I-H Knock-In Mouse that Carries a Nonsense Mutation Analogous to the Human IDUA-W402X Mutation

PubMed Central

Wang, Dan; Shukla, Charu; Liu, Xiaoli; Schoeb, Trenton R.; Clarke, Lorne A.; Bedwell, David M.; Keeling, Kim M.

2009-01-01

Here we report the characterization of a knock-in mouse model for the autosomal recessive disorder mucopolysaccharidosis type I-Hurler (MPS I-H), also known as Hurler syndrome. MPS I-H is the most severe form of α-L-iduronidase deficiency. α-L-iduronidase (encoded by the IDUA gene) is a lysosomal enzyme that participates in the degradation of dermatan sulfate and heparan sulfate. Using gene replacement methodology, a nucleotide change was introduced into the mouse Idua locus that resulted in a nonsense mutation at codon W392. The Idua-W392X mutation is analogous to the human IDUA-W402X mutation commonly found in MPS I-H patients. We found that the phenotype in homozygous Idua-W392X mice closely correlated with the human MPS I-H disease. Homozygous W392X mice showed no detectable α-L-iduronidase activity. We observed a defect in GAG degradation as evidenced by an increase in sulfated GAGs excreted in the urine and stored in multiple tissues. Histology and electron microscopy also revealed evidence of GAG storage in all tissues examined. Additional assessment revealed bone abnormalities and altered metabolism within the Idua-W392X mouse. This new mouse will provide an important tool to investigate therapeutic approaches for MPS I-H that cannot be addressed using current MPS I-H animal models. PMID:19751987

Role of serum angiotensin converting enzyme in sarcoidosis.

PubMed

Khan, A H; Ghani, F; Khan, A; Khan, M A; Khurshid, M

1998-05-01

This study was conducted to determine the role of Serum Angiotensin Converting Enzyme (SACE) as a marker in the differential diagnosis of pulmonary diseases and prognosis of sarcoidosis. A retrospective analysis of 113 medical records of patients at The Aga Khan University Hospital, with laboratory investigation for SACE was performed. Among 113 patients, 51 cases were found to have sarcoidosis, 44 of them had SACE levels greater than 52 IU/L (mean ACE 104.44). SACE levels were also found elevated in other clinical conditions like tuberculosis (mean 58.64 IU/L), but the enzyme level were less (p 0.04) than those found in sarcoidosis (mean (92.97 IU/L). SACE activity was found to be considerably lower in other chronic lung diseases such as, fibrosing alveolitis (mean 43.98 IU/L), interstitial lung disease (mean 42.11 IU/L) and chronic obstructive lung disease (mean 40.85 IU/L). Twenty patients of sarcoidosis, who received steroid treatment subsequently showed a decline in the SACE levels. SACE is a useful marker in differential diagnosis as 37.2% cases of sarcoidosis compared to only 9.09% of tuberculosis had SACE levels greater than 100 IU/L. In addition, our data also suggest that serum ACE is useful for the diagnosis as well as monitoring prognosis in sarcoidosis.

A virus-binding hot spot on human angiotensin-converting enzyme 2 is critical for binding of two different coronaviruses.

PubMed

Wu, Kailang; Chen, Lang; Peng, Guiqing; Zhou, Wenbo; Pennell, Christopher A; Mansky, Louis M; Geraghty, Robert J; Li, Fang

2011-06-01

How viruses evolve to select their receptor proteins for host cell entry is puzzling. We recently determined the crystal structures of NL63 coronavirus (NL63-CoV) and SARS coronavirus (SARS-CoV) receptor-binding domains (RBDs), each complexed with their common receptor, human angiotensin-converting enzyme 2 (hACE2), and proposed the existence of a virus-binding hot spot on hACE2. Here we investigated the function of this hypothetical hot spot using structure-guided biochemical and functional assays. The hot spot consists of a salt bridge surrounded by hydrophobic tunnel walls. Mutations that disturb the hot spot structure have significant effects on virus/receptor interactions, revealing critical energy contributions from the hot spot structure. The tunnel structure at the NL63-CoV/hACE2 interface is more compact than that at the SARS-CoV/hACE2 interface, and hence RBD/hACE2 binding affinities are decreased either by NL63-CoV mutations decreasing the tunnel space or by SARS-CoV mutations increasing the tunnel space. Furthermore, NL63-CoV RBD inhibits hACE2-dependent transduction by SARS-CoV spike protein, a successful application of the hot spot theory that has the potential to become a new antiviral strategy against SARS-CoV infections. These results suggest that the structural features of the hot spot on hACE2 were among the driving forces for the convergent evolution of NL63-CoV and SARS-CoV.

Modulation of substrate specificities of D-sialic acid aldolase through single mutations of Val-251.

PubMed

Chou, Chien-Yu; Ko, Tzu-Ping; Wu, Kuan-Jung; Huang, Kai-Fa; Lin, Chun-Hung; Wong, Chi-Huey; Wang, Andrew H-J

2011-04-22

In a recent directed-evolution study, Escherichia coli D-sialic acid aldolase was converted by introducing eight point mutations into a new enzyme with relaxed specificity, denoted RS-aldolase (also known formerly as L-3-deoxy-manno-2-octulosonic acid (L-KDO) aldolase), which showed a preferred selectivity toward L-KDO. To investigate the underlying molecular basis, we determined the crystal structures of D-sialic acid aldolase and RS-aldolase. All mutations are away from the catalytic center, except for V251I, which is near the opening of the (α/β)(8)-barrel and proximal to the Schiff base-forming Lys-165. The change of specificity from D-sialic acid to RS-aldolase can be attributed mainly to the V251I substitution, which creates a narrower sugar-binding pocket, but without altering the chirality in the reaction center. The crystal structures of D-sialic acid aldolase·l-arabinose and RS-aldolase·hydroxypyruvate complexes and five mutants (V251I, V251L, V251R, V251W, and V251I/V265I) of the D-sialic acid aldolase were also determined, revealing the location of substrate molecules and how the contour of the active site pocket was shaped. Interestingly, by mutating Val251 alone, the enzyme can accept substrates of varying size in the aldolase reactions and still retain stereoselectivity. The engineered D-sialic acid aldolase may find applications in synthesizing unnatural sugars of C(6) to C(10) for the design of antagonists and inhibitors of glycoenzymes.

Lifetime exercise intolerance with lactic acidosis as key manifestation of novel compound heterozygous ACAD9 mutations causing complex I deficiency.

PubMed

Schrank, Bertold; Schoser, Benedikt; Klopstock, Thomas; Schneiderat, Peter; Horvath, Rita; Abicht, Angela; Holinski-Feder, Elke; Augustis, Sarunas

2017-05-01

We report a 36-year-old female having lifetime exercise intolerance and lactic acidosis with nausea associated with novel compound heterozygous Acyl-CoA dehydrogenase 9 gene (ACAD9) mutations (p.Ala390Thr and p.Arg518Cys). ACAD9 is an assembly factor for the mitochondrial respiratory chain complex I. ACAD9 mutations are recognized as frequent causes of complex I deficiency. Our patient presented with exercise intolerance, rapid fatigue, and nausea since early childhood. Mild physical workload provoked the occurrence of nausea and vomiting repeatedly. Her neurological examination, laboratory findings and muscle biopsy demonstrated no abnormalities. A bicycle spiroergometry provoked significant lactic acidosis during and following exercise pointing towards a mitochondrial disorder. Subsequently, the analysis of respiratory chain enzyme activities in muscle revealed severe isolated complex I deficiency. Candidate gene sequencing revealed two novel heterozygous ACAD9 mutations. This patient report expands the mutational and phenotypic spectrum of diseases associated with mutations in ACAD9. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular diversity of tuliposide A-converting enzyme in the tulip.

PubMed

Nomura, Taiji; Tsuchigami, Aya; Ogita, Shinjiro; Kato, Yasuo

2013-01-01

Tuliposide A-converting enzyme (TCEA) catalyzes the conversion of 6-tuliposide A to its lactonized aglycon, tulipalin A, in the tulip (Tulipa gesneriana). The TgTCEA gene, isolated previously from petals, was transcribed in all tulip tissues but not in the bulbs despite the presence of TCEA activity, which allowed prediction of the presence of a TgTCEA isozyme gene preferentially expressed in the bulbs. Here, the TgTCEA-b gene, the TgTCEA homolog, was identified in bulbs. TgTCEA-b polypeptides showed approximately 77% identity to the petal TgTCEA. Functional characterization of the recombinant enzyme verified that TgTCEA-b encoded the TCEA. Moreover, the TgTCEA-b was found to be localized to plastids, as found for the petal TgTCEA. Transcript analysis revealed that TgTCEA-b was functionally transcribed in the bulb scales, unlike the TgTCEA gene, whose transcripts were absent there. In contrast, TgTCEA-b transcripts were in the minority in other tissues where TgTCEA transcripts were dominant, indicating a tissue preference for the transcription of those isozyme genes.

Mechanistic insight into the functional transition of the enzyme guanylate kinase induced by a single mutation

PubMed Central

Zhang, Yuebin; Niu, Huiyan; Li, Yan; Chu, Huiying; Shen, Hujun; Zhang, Dinglin; Li, Guohui

2015-01-01

Dramatic functional changes of enzyme usually require scores of alterations in amino acid sequence. However, in the case of guanylate kinase (GK), the functional novelty is induced by a single (S→P) mutation, leading to the functional transition of the enzyme from a phosphoryl transfer kinase into a phosphorprotein interaction domain. Here, by using molecular dynamic (MD) and metadynamics simulations, we provide a comprehensive description of the conformational transitions of the enzyme after mutating serine to proline. Our results suggest that the serine plays a crucial role in maintaining the closed conformation of wild-type GK and the GMP recognition. On the contrary, the S→P mutant exhibits a stable open conformation and loses the ability of ligand binding, which explains its functional transition from the GK enzyme to the GK domain. Furthermore, the free energy profiles (FEPs) obtained by metadymanics clearly demonstrate that the open-closed conformational transition in WT GK is positive correlated with the process of GMP binding, indicating the GMP-induced closing motion of GK enzyme, which is not observed in the mutant. In addition, the FEPs show that the S→P mutation can also leads to the mis-recognition of GMP, explaining the vanishing of catalytic activity of the mutant. PMID:25672880

Mechanistic insight into the functional transition of the enzyme guanylate kinase induced by a single mutation.

PubMed

Zhang, Yuebin; Niu, Huiyan; Li, Yan; Chu, Huiying; Shen, Hujun; Zhang, Dinglin; Li, Guohui

2015-02-12

Dramatic functional changes of enzyme usually require scores of alterations in amino acid sequence. However, in the case of guanylate kinase (GK), the functional novelty is induced by a single (S→P) mutation, leading to the functional transition of the enzyme from a phosphoryl transfer kinase into a phosphorprotein interaction domain. Here, by using molecular dynamic (MD) and metadynamics simulations, we provide a comprehensive description of the conformational transitions of the enzyme after mutating serine to proline. Our results suggest that the serine plays a crucial role in maintaining the closed conformation of wild-type GK and the GMP recognition. On the contrary, the S→P mutant exhibits a stable open conformation and loses the ability of ligand binding, which explains its functional transition from the GK enzyme to the GK domain. Furthermore, the free energy profiles (FEPs) obtained by metadymanics clearly demonstrate that the open-closed conformational transition in WT GK is positive correlated with the process of GMP binding, indicating the GMP-induced closing motion of GK enzyme, which is not observed in the mutant. In addition, the FEPs show that the S→P mutation can also leads to the mis-recognition of GMP, explaining the vanishing of catalytic activity of the mutant.

A Novel Lactone-Forming Carboxylesterase: Molecular Identification of a Tuliposide A-Converting Enzyme in Tulip1[W

PubMed Central

Nomura, Taiji; Ogita, Shinjiro; Kato, Yasuo

2012-01-01

Tuliposides, the glucose esters of 4-hydroxy-2-methylenebutanoate and 3,4-dihydroxy-2-methylenebutanoate, are major secondary metabolites in tulip (Tulipa gesneriana). Their lactonized aglycons, tulipalins, function as defensive chemicals due to their biological activities. We recently found that tuliposide-converting enzyme (TCE) purified from tulip bulbs catalyzed the conversion of tuliposides to tulipalins, but the possibility of the presence of several TCE isozymes was raised: TCE in tissues other than bulbs is different from bulb TCE. Here, to prove this hypothesis, TCE was purified from petals, which have the second highest TCE activity after bulbs. The purified enzyme, like the bulb enzyme, preferentially accepted tuliposides as substrates, with 6-tuliposide A the best substrate, which allowed naming the enzyme tuliposide A-converting enzyme (TCEA), but specific activity and molecular mass differed between the petal and bulb enzymes. After peptide sequencing, a novel cDNA (TgTCEA) encoding petal TCEA was isolated, and the functional characterization of the recombinant enzyme verified that TgTCEA catalyzes the conversion of 6-tuliposide A to tulipalin A. TgTCEA was transcribed in all tulip tissues but not in bulbs, indicating the presence of a bulb-specific TgTCEA, as suggested by the distinct enzymatic characters between the petal and bulb enzymes. Plastidial localization of TgTCEA enzyme was revealed, which allowed proposing a cytological mechanism of TgTCE-mediated tulipalin formation in the tulip defensive strategy. Site-directed mutagenesis of TgTCEA suggested that the oxyanion hole and catalytic triad characteristic of typical carboxylesterases are essential for the catalytic process of TgTCEA enzyme. To our knowledge, TgTCEA is the first identified member of the lactone-forming carboxylesterases, specifically catalyzing intramolecular transesterification. PMID:22474185

Association of Urinary N-Domain Angiotensin I-Converting Enzyme with Plasma Inflammatory Markers and Endothelial Function

PubMed Central

Fernandes, Fernanda B; Plavnik, Frida L; Teixeira, Andressa MS; Christofalo, Dejaldo MJ; Ajzen, Sergio A; Higa, Elisa MS; Ronchi, Fernanda A; Sesso, Ricardo CC; Casarini, Dulce E

2008-01-01

The aim of this study was to investigate the association between urinary 90 kDa N-domain Angiotensin I-converting enzyme (ACE) form with C-reactive protein (CRP) and homocysteine plasma levels (Hcy), urinary nitric oxide (NOu), and endothelial function (EF) in normotensive subjects. Forty healthy subjects were evaluated through brachial Doppler US to test the response to reactive hyperemia and a panel of blood tests to determine CRP and Hcy levels, NOu, and urinary ACE. They were divided into groups according to the presence (ACE90+) or absence (ACE90–) of the 90 kDa ACE, the presence (FH+) or absence (FH–) of family history of hypertension, and the presence or absence of these two variables FH+/ACE90+ and FH–/ACE90–. We found an impaired endothelial dilatation in subjects who presented the 90 kDa N-domain ACE as follows: 11.4% ± 5.3% in ACE90+ compared with 17.6% ± 7.1% in ACE90– group and 12.4% ± 5.6% in FH+/ACE90+ compared with 17.7% ± 6.2% in FH–/ACE90– group, P < 0.05. Hcy and CRP levels were statistically significantly lower in FH+/ACE90+ than in FH–/ACE90– group, as follows: 10.0 ± 2.3 μM compared with 12.7 ± 1.5 μM, and 1.3 ± 1.8 mg/L compared with 3.6 ± 2.0 mg/L, respectively. A correlation between flow-mediated dilatation (FMD) and CRP, Hcy, and NOu levels was not found. Our study suggests a reduction in the basal NO production confirmed by NOu analysis in subjects with the 90 kDa N-domain ACE isoform alone or associated with a family history of hypertension. Our data suggest that the presence of the 90 kDa N-domain ACE itself may have a negative impact on flow-mediated dilatation stimulated by reactive hyperemia. PMID:18475311

The chlorophyll-deficient golden leaf mutation in cucumber is due to a single nucleotide substitution in CsChlI for magnesium chelatase I subunit.

PubMed

Gao, Meiling; Hu, Liangliang; Li, Yuhong; Weng, Yiqun

2016-10-01

The cucumber chlorophyll-deficient golden leaf mutation is due to a single nucleotide substitution in the CsChlI gene for magnesium chelatase I subunit which plays important roles in the chlorophyll biosynthesis pathway. The Mg-chelatase catalyzes the insertion of Mg(2+) into the protoporphyrin IX in the chlorophyll biosynthesis pathway, which is a protein complex encompassing three subunits CHLI, CHLD, and CHLH. Chlorophyll-deficient mutations in genes encoding the three subunits have played important roles in understanding the structure, function and regulation of this important enzyme. In an EMS mutagenesis population, we identified a chlorophyll-deficient mutant C528 with golden leaf color throughout its development which was viable and able to set fruits and seeds. Segregation analysis in multiple populations indicated that this leaf color mutation was recessively inherited and the green color showed complete dominance over golden color. Map-based cloning identified CsChlI as the candidate gene for this mutation which encoded the CHLI subunit of cucumber Mg-chelatase. The 1757-bp CsChlI gene had three exons and a single nucleotide change (G to A) in its third exon resulted in an amino acid substitution (G269R) and the golden leaf color in C528. This mutation occurred in the highly conserved nucleotide-binding domain of the CHLI protein in which chlorophyll-deficient mutations have been frequently identified. The mutant phenotype, CsChlI expression pattern and the mutated residue in the CHLI protein suggested the mutant allele in C528 is unique among mutations identified so far in different species. This golden leaf mutant not only has its potential in cucumber breeding, but also provides a useful tool in understanding the CHLI function and its regulation in the chlorophyll biosynthesis pathway as well as chloroplast development.

Cloning and expression of synthetic genes encoding angiotensin-I converting enzyme (ACE)-inhibitory bioactive peptides in Bifidobacterium pseudocatenulatum.

PubMed

Losurdo, Luca; Quintieri, Laura; Caputo, Leonardo; Gallerani, Raffaele; Mayo, Baltasar; De Leo, Francesca

2013-03-01

A wide range of biopeptides potentially able to lower blood pressure through inhibition of the angiotensin-I converting enzyme (ACE) is produced in fermented foods by proteolytic starter cultures. This work applies a procedure based on recombinant DNA technologies for the synthesis and expression of three ACE-inhibitory peptides using a probiotic cell factory. ACE-inhibitory genes and their pro-active precursors were designed, synthesized by PCR, and cloned in Escherichia coli; after which, they were cloned into the pAM1 E. coli-bifidobacteria shuttle vector. After E. coli transformation, constructs carrying the six recombinant clones were electrotransferred into the Bifidobacterium pseudocatenulatum M115 probiotic strain. Interestingly, five of the six constructs proved to be stable. Their expression was confirmed by reverse transcription PCR. Furthermore, transformed strains displayed ACE-inhibitory activity linearly correlated to increasing amounts of cell-free cellular lysates. In particular, 50 μg of lysates from constructs pAM1-Pro-BP3 and pAM1-BP2 showed a 50% higher ACE-inhibitory activity than that of the controls. As a comparison, addition of 50 ng of Pro-BP1 and Pro-BP3 synthetic peptides to 50 μg of cell-free extracts of B. pseudocatenulatum M115 wild-type strain showed an average of 67% of ACE inhibition; this allowed estimating the amount of the peptides produced by the transformants. Engineering of bifidobacteria for the production of biopeptides is envisioned as a promising cell factory model system. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Gene encoding a deubiquitinating enzyme is mutated in artesunate- and chloroquine-resistant rodent malaria parasites.

PubMed

Hunt, Paul; Afonso, Ana; Creasey, Alison; Culleton, Richard; Sidhu, Amar Bir Singh; Logan, John; Valderramos, Stephanie G; McNae, Iain; Cheesman, Sandra; do Rosario, Virgilio; Carter, Richard; Fidock, David A; Cravo, Pedro

2007-07-01

Artemisinin- and artesunate-resistant Plasmodium chabaudi mutants, AS-ART and AS-ATN, were previously selected from chloroquine-resistant clones AS-30CQ and AS-15CQ respectively. Now, a genetic cross between AS-ART and the artemisinin-sensitive clone AJ has been analysed by Linkage Group Selection. A genetic linkage group on chromosome 2 was selected under artemisinin treatment. Within this locus, we identified two different mutations in a gene encoding a deubiquitinating enzyme. A distinct mutation occurred in each of the clones AS-30CQ and AS-ATN, relative to their respective progenitors in the AS lineage. The mutations occurred independently in different clones under drug selection with chloroquine (high concentration) or artesunate. Each mutation maps to a critical residue in a homologous human deubiquitinating protein structure. Although one mutation could theoretically account for the resistance of AS-ATN to artemisinin derivates, the other cannot account solely for the resistance of AS-ART, relative to the responses of its sensitive progenitor AS-30CQ. Two lines of Plasmodium falciparum with decreased susceptibility to artemisinin were also selected. Their drug-response phenotype was not genetically stable. No mutations in the UBP-1 gene encoding the P. falciparum orthologue of the deubiquitinating enzyme were observed. The possible significance of these mutations in parasite responses to chloroquine or artemisinin is discussed.

Radioligand binding reveals chymase as the predominant enzyme for mediating tissue conversion of angiotensin I in the normal human heart.

PubMed

Katugampola, Sidath D; Davenport, Anthony P

2002-01-01

We investigated the binding characteristics of angiotensin receptors and used this assay to determine the predominant enzyme capable of converting angiotensin I in the human left ventricle. In homogenates of human left ventricle, (125)I-[Sar(1),Ile(8)]angiotensin II bound with sub-nanomolar affinity, with a corresponding K(D) of 0.42+/-0.09 nM, a B(max) of 11.2+/-2.3 fmol.mg(-1) protein and a Hill slope of 1.04+/-0.04. The rank order of inhibitory potency of competing ligands for the (125)I-[Sar(1),Ile(8)]angiotensin II binding site was CGP42112>angiotensin II> or =angiotensin III=angiotensin I>losartan. The angiotensin type II (AT(2)) receptor predominated in the human left ventricle over the angiotensin type I (AT(1)) receptor, with an approximate AT(1)/AT(2) receptor ratio of 35:65. No specific (125)I-angiotensin IV binding sites could be detected in the human left ventricle. Using competitive radioligand binding assays, we were able to demonstrate that the chymase/cathepsin G enzyme inhibitor chymostatin was more potent than the angiotensin-converting enzyme (ACE) inhibitor captopril at inhibiting the conversion of angiotensin I in the human left ventricle. Aprotonin (an inhibitor of cathepsin G but of not chymase) had no effect on angiotensin I conversion, suggesting that the majority of the conversion was mediated by chymase. Thus, although the current therapies used for the renin-angiotensin system have focused on ACE inhibitors and AT(1) receptor antagonists, the left ventricle of the human heart expresses mainly AT(2) receptors and the tissue-specific conversion of angiotensin I occurs predominantly via chymase rather than ACE.

Enzymes processing somatostatin precursors: an Arg-Lys esteropeptidase from the rat brain cortex converting somatostatin-28 into somatostatin-14.

PubMed Central

Gluschankof, P; Morel, A; Gomez, S; Nicolas, P; Fahy, C; Cohen, P

1984-01-01

The post-translational proteolytic conversion of somatostatin-14 precursors was studied to characterize the enzyme system responsible for the production of the tetradecapeptide either from its 15-kDa precursor protein or from its COOH-terminal fragment, somatostatin-28. A synthetic undecapeptide Pro-Arg-Glu-Arg-Lys-Ala-Gly-Ala-Lys-Asn-Tyr(NH2), homologous to the amino acid sequence of the octacosapeptide at the putative Arg-Lys cleavage locus, was used as substrate, after 125I labeling on the COOH-terminal tyrosine residue. A 90-kDa proteolytic activity was detected in rat brain cortex extracts after molecular sieve fractionation followed by ion exchange chromatography. The protease released the peptide 125I-Ala-Gly-Ala-Lys-Asn-Tyr(NH2) from the synthetic undecapeptide substrate and converted somatostatin-28 into somatostatin-14 under similar conditions (pH 7.0). Under these experimental conditions, the product tetradecapeptide was not further degraded by the enzyme. In contrast, the purified 15-kDa hypothalamic precursor remained unaffected when exposed to the proteolytic enzyme under identical conditions. It is concluded that this Arg-Lys esteropeptidase from the brain cortex may be involved in the in vivo processing of the somatostatin-28 fragment of prosomatostatin into somatostatin-14, the former species being an obligatory intermediate in a two-step proteolytic mechanism leading to somatostatin-14. PMID:6149550

Effects of curcumin on angiotensin-converting enzyme gene expression, oxidative stress and anti-oxidant status in thioacetamide-induced hepatotoxicity.

PubMed

Fazal, Yumna; Fatima, Syeda Nuzhat; Shahid, Syed Muhammad; Mahboob, Tabassum

2015-12-01

This study aimed to evaluate the protective effects of curcumin on angiotensin-converting enzyme (ACE) gene expression, oxidative stress and anti-oxidant status in thioacetamide (TAA)-induced hepatotoxicity in rats. Total 32 albino Wistar rats (male, 200-250 g) were divided into six groups (n=8). Group 1: untreated controls; Group 2: received TAA (200 mg/kg body weight (b.w.); i.p.) for 12 weeks; Group 3: received curcumin (75 mg/kg b.w.) for 24 weeks; Group 4: received TAA (200 mg/kg b.w.; i.p.) for 12 weeks+curcumin (75 mg/kg b.w.) for 12 weeks. A significantly higher ACE gene expression was observed in TAA-induced groups as compared with control, indicating more synthesis of ACE proteins. Treatment with curcumin suppressed ACE expression in TAA liver and reversed the toxicity produced. TAA treatment results in higher lipid peroxidation and lower GSH, SOD and CAT than the normal, and this produces oxidative stress in the liver. Cirrhotic conditions were confirmed by serum enzymes (ALT, AST and ALP) as well as histopathological observations. Curcumin treatment reduced oxidative stress in animals by scavenging reactive oxygen species, protecting the anti-oxidant enzymes from being denatured and reducing the oxidative stress marker lipid peroxidation. Curcumin treatment restores hepatocytes, damaged by TAA, and protects liver tissue approaching cirrhosis. © The Author(s) 2014.

Implications of the angiotensin converting enzyme gene insertion/deletion polymorphism in health and disease: a snapshot review

PubMed Central

Gard, Paul R

2010-01-01

This review considers the 250+ papers concerning the association of the angiotensin converting enzyme (ACE) gene insertion/deletion polymorphism (rs1799752) and various disease conditions published in 2009. The deletion allele occurs in approximately 55% of the population and is associated with increased activity of the ACE enzyme. It might be predicted that the D allele, therefore, might be associated with pathologies involving increased activity of the renin-angiotensin system. The D allele was seen to be associated with an increased risk of hypertension, pre-eclampsia, heart failure, cerebral infarct, diabetic nephropathy, encephalopathy, asthma, severe hypoglycaemia in diabetes, gastric cancer (in Caucasians) and poor prognosis following kidney transplant. On the positive side, the D allele appears to offer protection against schizophrenia and chronic periodontitis and confers greater up-per-body strength in old age. The I allele, meanwhile, offers improved endurance/athletic performance and aerobic capacity as determined by lung function tests, although it does increase the risk of oral squamous cell carcinoma and obstructive sleep apnoea in hypertensives. PMID:21537387

All-optical and broadband microwave fundamental/sub-harmonic I/Q down-converters.

PubMed

Gao, Yongsheng; Wen, Aijun; Jiang, Wei; Fan, Yangyu; He, You

2018-03-19

Microwave I/Q down-converters are frequently used in image-reject super heterodyne receivers, zero intermediate frequency (zero-IF) receivers, and phase/frequency discriminators. However, due to the electronic bottleneck, conventional microwave I/Q mixers face a serious bandwidth limitation, I/Q imbalance, and even-order distortion. In this paper, photonic microwave fundamental and sub-harmonic I/Q down-converters are presented using a polarization division multiplexing dual-parallel Mach-Zehnder modulator (PDM-DPMZM). Thanks to all-optical manipulation, the proposed system features an ultra-wide operating band (7-40 GHz in the fundamental I/Q down-converter, and 10-40 GHz in the sub-harmonic I/Q down-converter) and an excellent I/Q balance (maximum 0.7 dB power imbalance and 1 degree phase imbalance). The conversion gain, noise figure (NF), even-order distortion, and spurious free dynamic range (SFDR) are also improved by LO power optimization and balanced detection. Using the proposed system, a high image rejection ratio is demonstrated for a super heterodyne receiver, and good EVMs over a wide RF power range is demonstrated for a zero-IF receiver. The proposed broadband photonic microwave fundamental and sub-harmonic I/Q down-converters may find potential applications in multi-band satellite, ultra-wideband radar and frequency-agile electronic warfare systems.

Experimental Determination and Prediction of the Fitness Effects of Random Point Mutations in the Biosynthetic Enzyme HisA

PubMed Central

Lundin, Erik; Tang, Po-Cheng; Guy, Lionel; Näsvall, Joakim; Andersson, Dan I

2018-01-01

Abstract The distribution of fitness effects of mutations is a factor of fundamental importance in evolutionary biology. We determined the distribution of fitness effects of 510 mutants that each carried between 1 and 10 mutations (synonymous and nonsynonymous) in the hisA gene, encoding an essential enzyme in the l-histidine biosynthesis pathway of Salmonella enterica. For the full set of mutants, the distribution was bimodal with many apparently neutral mutations and many lethal mutations. For a subset of 81 single, nonsynonymous mutants most mutations appeared neutral at high expression levels, whereas at low expression levels only a few mutations were neutral. Furthermore, we examined how the magnitude of the observed fitness effects was correlated to several measures of biophysical properties and phylogenetic conservation.We conclude that for HisA: (i) The effect of mutations can be masked by high expression levels, such that mutations that are deleterious to the function of the protein can still be neutral with regard to organism fitness if the protein is expressed at a sufficiently high level; (ii) the shape of the fitness distribution is dependent on the extent to which the protein is rate-limiting for growth; (iii) negative epistatic interactions, on an average, amplified the combined effect of nonsynonymous mutations; and (iv) no single sequence-based predictor could confidently predict the fitness effects of mutations in HisA, but a combination of multiple predictors could predict the effect with a SD of 0.04 resulting in 80% of the mutations predicted within 12% of their observed selection coefficients. PMID:29294020

Hydrolysis by somatic angiotensin-I converting enzyme of basic dipeptides from a cholecystokinin/gastrin and a LH-RH peptide extended at the C-terminus with gly-Arg/Lys-arg, but not from diarginyl insulin.

PubMed

Isaac, R E; Michaud, A; Keen, J N; Williams, T A; Coates, D; Wetsel, W C; Corvol, P

1999-06-01

Endoproteolytic cleavage of protein prohormones often generates intermediates extended at the C-terminus by Arg-Arg or Lys-Arg, the removal of which by a carboxypeptidase (CPE) is normally an important step in the maturation of many peptide hormones. Recent studies in mice that lack CP activity indicate the existence of alternative tissue or plasma enzymes capable of removing C-terminal basic residues from prohormone intermediates. Using inhibitors of angiotensin I-converting enzyme (ACE) and CP, we show that both these enzymes in mouse serum can remove the basic amino acids from the C-terminus of CCK5-GRR and LH-RH-GKR, but only CP is responsible for converting diarginyl insulin to insulin. ACE activity removes C-terminal dipeptides to generate the Gly-extended peptides, whereas CP hydrolysis gives rise to CCK5-GR and LH-RH-GK, both of which are susceptible to the dipeptidyl carboxypeptidase activity of ACE. Somatic ACE has two similar protein domains (the N-domain and the C-domain), each with an active site that can display different substrate specificities. CCK5-GRR is a high-affinity substrate for both the N-domain and C-domain active sites of human sACE (Km of 9.4 microm and 9.0 microm, respectively) with the N-domain showing greater efficiency (kcat : Km ratio of 2.6 in favour of the N-domain). We conclude that somatic forms of ACE should be considered as alternatives to CPs for the removal of basic residues from some Arg/Lys-extended peptides.

Angiotensin-converting enzyme gene polymorphisms and hypertension in occupational noise exposure in Egypt

PubMed Central

Zawilla, Nermin; Shaker, Dalia; Abdelaal, Amaal; Aref, Wael

2014-01-01

Background: The gene–environment interaction in the pathogenesis of hypertension has not been extensively studied in occupational noise. Objectives: The aim of this study was to determine the relationship between noise and hypertension in Egyptian workers, the interaction of angiotensin-converting enzyme (ACE) gene polymorphisms as modifiers, and the possible relationship between noise hearing impairment and hypertension. Methods: Study subjects were divided into two groups depending on noise exposure level. The control group (n = 161) was exposed to noise intensity <85 dB and the exposed group (n = 217) was exposed to noise intensity ≧85 dB. A polymerase chain reaction was used to differentiate the various genotypes of ACE insertion/deletion (I/D) and ACE G2350A. Results: Noise significantly increased the likelihood of hypertension. Carriers of the genotypes AG, GG, and DD were vulnerable to hypertension on noise exposure. No association between hypertension and hearing impairment or noise-induced hearing loss (NIHL) was found. Conclusion: Our results support the association between ACE gene polymorphisms and occurrence of hypertension in noise-exposed workers. PMID:25000107

Functional Trade-Offs in Promiscuous Enzymes Cannot Be Explained by Intrinsic Mutational Robustness of the Native Activity.

PubMed

Kaltenbach, Miriam; Emond, Stephane; Hollfelder, Florian; Tokuriki, Nobuhiko

2016-10-01

The extent to which an emerging new function trades off with the original function is a key characteristic of the dynamics of enzyme evolution. Various cases of laboratory evolution have unveiled a characteristic trend; a large increase in a new, promiscuous activity is often accompanied by only a mild reduction of the native, original activity. A model that associates weak trade-offs with "evolvability" was put forward, which proposed that enzymes possess mutational robustness in the native activity and plasticity in promiscuous activities. This would enable the acquisition of a new function without compromising the original one, reducing the benefit of early gene duplication and therefore the selection pressure thereon. Yet, to date, no experimental study has examined this hypothesis directly. Here, we investigate the causes of weak trade-offs by systematically characterizing adaptive mutations that occurred in two cases of evolutionary transitions in enzyme function: (1) from phosphotriesterase to arylesterase, and (2) from atrazine chlorohydrolase to melamine deaminase. Mutational analyses in various genetic backgrounds revealed that, in contrast to the prevailing model, the native activity is less robust to mutations than the promiscuous activity. For example, in phosphotriesterase, the deleterious effect of individual mutations on the native phosphotriesterase activity is much larger than their positive effect on the promiscuous arylesterase activity. Our observations suggest a revision of the established model: weak trade-offs are not caused by an intrinsic robustness of the native activity and plasticity of the promiscuous activity. We propose that upon strong adaptive pressure for the new activity without selection against the original one, selected mutations will lead to the largest possible increases in the new function, but whether and to what extent they decrease the old function is irrelevant, creating a bias towards initially weak trade-offs and the

Flavonoids-Rich Orthosiphon stamineus Extract as New Candidate for Angiotensin I-Converting Enzyme Inhibition: A Molecular Docking Study.

PubMed

Shafaei, Armaghan; Sultan Khan, Md Shamsuddin; F A Aisha, Abdalrahim; Abdul Majid, Amin Malik Shah; Hamdan, Mohammad Razak; Mordi, Mohd Nizam; Ismail, Zhari

2016-11-09

This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of Orthosiphon stamineus (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure-activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by LeadIT-FlexX : BioSolveIT's LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC 50 value (45.77 ± 1.17 µg/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC 50 15.35 ± 4.49 µg/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% ± 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE.

Convergent evidences from human and animal studies implicate angiotensin I-converting enzyme activity in cognitive performance in schizophrenia.

PubMed

Gadelha, A; Vendramini, A M; Yonamine, C M; Nering, M; Berberian, A; Suiama, M A; Oliveira, V; Lima-Landman, M T; Breen, G; Bressan, R A; Abílio, V; Hayashi, M A F

2015-12-08

In schizophrenia (SCZ), higher angiotensin I-converting enzyme (ACE) levels have been reported in patient's blood and cerebrospinal fluid (CSF). Hereby, we propose to explore whether the ACE activity levels are associated to cognitive performance in SCZ. Seventy-two patients with SCZ or schizoaffective disorder diagnosis, and 69 healthy controls (HCs) underwent a cognitive battery with parallel collection of peripheral blood samples to measure ACE activity. Significant higher ACE activity levels were confirmed in the plasma of SCZ patients compared with HCs (Student's t=-5.216; P<0.001). ACE activity significantly correlated to Hopkins delayed recall measures (r=-0.247; P=0.004) and Hopkins total (r=-0.214; P=0.012). Subjects grouped as high ACE activity (above average) had worse performance compared with low ACE activity level group for Hopkins delayed recall measure, even after correction for clinical condition, age, gender and years of education (P=0.029). The adjusted R squared for this final model was 0.343. This result was evident only comparing extreme groups for ACE activity, when splitting the sample in three groups with similar number of subjects. To clarify this finding, we performed an evaluation of the cognitive performance of transgenic mice with three copies of ACE gene in novel object recognition (NOR) test, which showed that such animals presented impairment in NOR (P<0.05) compared with two copies of wild-type animals. The results observed in SCZ patients and animal model suggest both the association of ACE to cognitive deficits in SCZ. This finding may support the evaluation of novel treatment protocols and/or of innovative drugs for specific intervention of cognitive deficits in SCZ envisioning concomitant ACE activity and behavior evaluations.

Identification of parallel and divergent optimization solutions for homologous metabolic enzymes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Standaert, Robert F.; Giannone, Richard J.; Michener, Joshua K.

Here, metabolic pathway assembly typically involves the expression of enzymes from multiple organisms in a single heterologous host. Ensuring that each enzyme functions effectively can be challenging, since many potential factors can disrupt proper pathway flux. Here, we compared the performance of two enzyme homologs in a pathway engineered to allow Escherichia coli to grow on 4-hydroxybenzoate (4-HB), a byproduct of lignocellulosic biomass deconstruction. Single chromosomal copies of the 4-HB 3-monooxygenase genes pobA and praI, from Pseudomonas putida KT2440 and Paenibacillus sp. JJ-1B, respectively, were introduced into a strain able to metabolize protocatechuate (PCA), the oxidation product of 4-HB. Neithermore » enzyme initially supported consistent growth on 4-HB. Experimental evolution was used to identify mutations that improved pathway activity. For both enzymes, silent mRNA mutations were identified that increased enzyme expression. With pobA, duplication of the genes for PCA metabolism allowed growth on 4-HB. However, with praI, growth required a mutation in the 4-HB/PCA transporter pcaK that increased intracellular concentrations of 4-HB, suggesting that flux through PraI was limiting. These findings demonstrate the value of directed evolution strategies to rapidly identify and overcome diverse factors limiting enzyme activity.« less

Identification of parallel and divergent optimization solutions for homologous metabolic enzymes

DOE PAGES

Standaert, Robert F.; Giannone, Richard J.; Michener, Joshua K.

2018-04-18

Here, metabolic pathway assembly typically involves the expression of enzymes from multiple organisms in a single heterologous host. Ensuring that each enzyme functions effectively can be challenging, since many potential factors can disrupt proper pathway flux. Here, we compared the performance of two enzyme homologs in a pathway engineered to allow Escherichia coli to grow on 4-hydroxybenzoate (4-HB), a byproduct of lignocellulosic biomass deconstruction. Single chromosomal copies of the 4-HB 3-monooxygenase genes pobA and praI, from Pseudomonas putida KT2440 and Paenibacillus sp. JJ-1B, respectively, were introduced into a strain able to metabolize protocatechuate (PCA), the oxidation product of 4-HB. Neithermore » enzyme initially supported consistent growth on 4-HB. Experimental evolution was used to identify mutations that improved pathway activity. For both enzymes, silent mRNA mutations were identified that increased enzyme expression. With pobA, duplication of the genes for PCA metabolism allowed growth on 4-HB. However, with praI, growth required a mutation in the 4-HB/PCA transporter pcaK that increased intracellular concentrations of 4-HB, suggesting that flux through PraI was limiting. These findings demonstrate the value of directed evolution strategies to rapidly identify and overcome diverse factors limiting enzyme activity.« less

Identification of parallel and divergent optimization solutions for homologous metabolic enzymes.

PubMed

Standaert, Robert F; Giannone, Richard J; Michener, Joshua K

2018-06-01

Metabolic pathway assembly typically involves the expression of enzymes from multiple organisms in a single heterologous host. Ensuring that each enzyme functions effectively can be challenging, since many potential factors can disrupt proper pathway flux. Here, we compared the performance of two enzyme homologs in a pathway engineered to allow Escherichia coli to grow on 4-hydroxybenzoate (4-HB), a byproduct of lignocellulosic biomass deconstruction. Single chromosomal copies of the 4-HB 3-monooxygenase genes pobA and praI , from Pseudomonas putida KT2440 and Paenibacillus sp. JJ-1B, respectively, were introduced into a strain able to metabolize protocatechuate (PCA), the oxidation product of 4-HB. Neither enzyme initially supported consistent growth on 4-HB. Experimental evolution was used to identify mutations that improved pathway activity. For both enzymes, silent mRNA mutations were identified that increased enzyme expression. With pobA , duplication of the genes for PCA metabolism allowed growth on 4-HB. However, with praI , growth required a mutation in the 4-HB/PCA transporter pcaK that increased intracellular concentrations of 4-HB, suggesting that flux through PraI was limiting. These findings demonstrate the value of directed evolution strategies to rapidly identify and overcome diverse factors limiting enzyme activity.

Angiotensin converting enzyme over expression in myelocytes enhances the immune response

PubMed Central

Bernstein, Kenneth E.; Gonzalez-Villalobos, Romer A.; Giani, Jorge F.; Shah, Kandarp; Bernstein, Ellen; Janjulia, Tea; Koronyo, Yosef; Shi, Peng D.; Koronyo-Hamaoui, Maya; Fuchs, Sebastien; Shen, Xiao Z.

2015-01-01

Angiotensin converting enzyme (ACE) plays an important role in blood pressure control. ACE also has effects on renal function, reproduction, hematopoiesis and several aspects of the immune response. ACE 10/10 mice over express ACE in monocytic cells; macrophages from ACE 10/10 mice demonstrate increased polarization towards a proinflammatory phenotype. As a result, ACE 10/10 mice have a highly effective immune response following challenge with either melanoma, bacterial infection or Alzheimer’s disease. The ACE 10/10 mice suggest that enhanced monocytic function greatly contributes to the ability of the immune response to defend against a wide variety of antigenic and non-antigenic challenges. PMID:24633750

In vitro digestion of purified β-casein variants A(1), A(2), B, and I: effects on antioxidant and angiotensin-converting enzyme inhibitory capacity.

PubMed

Petrat-Melin, B; Andersen, P; Rasmussen, J T; Poulsen, N A; Larsen, L B; Young, J F

2015-01-01

Genetic polymorphisms of bovine milk proteins affect the protein profile of the milk and, hence, certain technological properties, such as casein (CN) number and cheese yield. However, reports show that such polymorphisms may also affect the health-related properties of milk. Therefore, to gain insight into their digestion pattern and bioactive potential, β-CN was purified from bovine milk originating from cows homozygous for the variants A(1), A(2), B, and I by a combination of cold storage, ultracentrifugation, and acid precipitation. The purity of the isolated β-CN was determined by HPLC, variants were verified by mass spectrometry, and molar extinction coefficients at λ=280nm were determined. β-Casein from each of the variants was subjected to in vitro digestion using pepsin and pancreatic enzymes. Antioxidant and angiotensin-converting enzyme (ACE) inhibitory capacities of the hydrolysates were assessed at 3 stages of digestion and related to that of the undigested samples. Neither molar extinction coefficients nor overall digestibility varied significantly between these 4 variants; however, clear differences in digestion pattern were indicated by gel electrophoresis. In particular, after 60min of pepsin followed by 5min of pancreatic enzyme digestion, one ≈4kDa peptide with the N-terminal sequence (106)H-K-E-M-P-F-P-K- was absent from β-CN variant B. This is likely a result of the (122)Ser to (122)Arg substitution in variant B introducing a novel trypsin cleavage site, leading to the changed digestion pattern. All investigated β-CN variants exhibited a significant increase in antioxidant capacity upon digestion, as measured by the Trolox-equivalent antioxidant capacity assay. After 60min of pepsin + 120min of pancreatic enzyme digestion, the accumulated increase in antioxidant capacity was ≈1.7-fold for the 4 β-CN variants. The ACE inhibitory capacity was also significantly increased by digestion, with the B variant reaching the highest inhibitory

Effect of protease inhibitors on angiotensin-converting enzyme activity in human T-lymphocytes.

PubMed

Petrov, V; Fagard, R; Lijnen, P

2000-05-01

The purpose of these investigations was to determine whether the aminopeptidase B and leucine aminopeptidase inhibitor bestatin, the chymase inhibitor chymostatin, the calpain inhibitor E-64, and the neutral serine protease inhibitor leupeptin affect the angiotensin converting enzyme (ACE) activity in T-lymphocytes. ACE activity in homogenates of T-lymphocytes or in intact T-lymphocytes in suspension was measured by determining fluorimetrically histidyl-leucine, formed from the conversion of hippuryl-histidyl-leucine, coupled with ophtaldialdehyde. The effect of various concentrations (10(-9) to 10(-3) mol/L) of the angiotensin-converting enzyme inhibitors lisinopril and captopril and of the various protease inhibitors on ACE activity was studied. Lisinopril and captopril reduced the ACE activity in homogenates of T-lymphocytes in a concentration-dependent manner. Lisinopril exhibited a more pronounced inhibition of ACE in T-lymphocytes than did captopril. Chymostatin and E-64 had no effect on the ACE activity in T-lymphocytes, whereas leupeptin inhibited its activity in a dose-dependent fashion. Bestatin, on the contrary, increased the ACE activity in homogenates of T-lymphocytes as well as in intact T-lymphocytes in proportion to the concentration. Our data showed that the ACE activity in T-lymphocytes was stimulated by bestatin and inhibited by leupeptin, whereas chymostatin and E-64 did not affect the ACE activity in T-lymphocytes.

The mitochondrial 13513G>A mutation is associated with Leigh disease phenotypes independent of complex I deficiency in muscle.

PubMed

Brautbar, Ariel; Wang, Jing; Abdenur, Jose E; Chang, Richard C; Thomas, Janet A; Grebe, Theresa A; Lim, Cynthia; Weng, Shao-Wen; Graham, Brett H; Wong, Lee-Jun

2008-08-01

The mitochondrial 13513G>A (D393N) mutation in the ND5 subunit of the respiratory chain complex I was initially described in association with MELAS syndrome. Recent observations have linked this mutation to Leigh disease. We screened for the 13513G>A mutation in a cohort of 265 patients with Leigh and Leigh-like disease. The mutation was found in a total of 5 patients. An additional patient who had clinical presentation consistent with a Leigh-like phenotype but with a normal brain MRI was added to the cohort. None of an additional 88 patients meeting MELAS disease criteria, nor 56 patients with respiratory chain deficiency screened for the 13513G>A were found positive for the mutation. The most frequent clinical manifestations in our patients were hypotonia, ocular and cerebellar involvement. Low mutation heteroplasmy in the range of 20-40% was observed in all 6 patients. This observation is consistent with the previously reported low heteroplasmy of this mutation in some patients with the 13513G>A mutation and complex I deficiency. However, normal complex I activity was observed in two patients in our cohort. As most patients with Leigh-like disease and the 13513G>A mutation have been described with complex I deficiency, this report adds to the previously reported subset of patients with normal respiratory complex function. We conclude that in any patient with Leigh or Leigh-like disease, testing for the 13513G>A mutation is clinically relevant and low mutant loads in blood or muscle may be considered pathogenic, in the presence of normal respiratory chain enzyme activities.

Gene encoding a deubiquitinating enzyme is mutated in artesunate- and chloroquine-resistant rodent malaria parasites§

PubMed Central

Hunt, Paul; Afonso, Ana; Creasey, Alison; Culleton, Richard; Sidhu, Amar Bir Singh; Logan, John; Valderramos, Stephanie G; McNae, Iain; Cheesman, Sandra; do Rosario, Virgilio; Carter, Richard; Fidock, David A; Cravo, Pedro

2007-01-01

Artemisinin- and artesunate-resistant Plasmodium chabaudi mutants, AS-ART and AS-ATN, were previously selected from chloroquine-resistant clones AS-30CQ and AS-15CQ respectively. Now, a genetic cross between AS-ART and the artemisinin-sensitive clone AJ has been analysed by Linkage Group Selection. A genetic linkage group on chromosome 2 was selected under artemisinin treatment. Within this locus, we identified two different mutations in a gene encoding a deubiquitinating enzyme. A distinct mutation occurred in each of the clones AS-30CQ and AS-ATN, relative to their respective progenitors in the AS lineage. The mutations occurred independently in different clones under drug selection with chloroquine (high concentration) or artesunate. Each mutation maps to a critical residue in a homologous human deubiquitinating protein structure. Although one mutation could theoretically account for the resistance of AS-ATN to artemisinin derivates, the other cannot account solely for the resistance of AS-ART, relative to the responses of its sensitive progenitor AS-30CQ. Two lines of Plasmodium falciparum with decreased susceptibility to artemisinin were also selected. Their drug-response phenotype was not genetically stable. No mutations in the UBP-1 gene encoding the P. falciparum orthologue of the deubiquitinating enzyme were observed. The possible significance of these mutations in parasite responses to chloroquine or artemisinin is discussed. PMID:17581118

Review of Angiotensin-converting Enzyme Inhibitory Assay: Rapid Method in Drug Discovery of Herbal Plants

PubMed Central

Ahmad, Islamudin; Yanuar, Arry; Mulia, Kamarza; Mun’im, Abdul

2017-01-01

The renin-angiotensin-aldosterone system is a signaling pathway which responsible in the blood pressure regulation. Angiotensin-converting enzyme (ACE) is one of the key elements responsible for the hypertensive mechanism. It converts angiotensin-I to angiotensin-II. The discovery history of the ACE inhibitory activity assay method has been through a long stage for decades and development continues until today. The ACE inhibitory activity has become an effective screening method in the search for new antihypertensive agents from herbal plants. Some of in vitro assay methods were used to examine the activity of ACE inhibitors based on the substrate usage, such as; Cushman and Cheung Method using a substrate hippuryl-histidyl-leucine (HHL), Holmquist method using a substrate furanacryloyl-tripeptide, Elbl and Wagner method using a substrate benzoil-[l-14C] glicyl-L-histidine-L-leucine, Carmel and Yaron method using a substrate o-aminobenzoylglycyl-p-nitrophenylalanilproline, and Lam method using 3-hydroxybutyrylglycyl-glycyl-glycine as substrate. Several different methods to measure the results of enzymatic reactions or separating substrate with products, including spectrophotometric, fluorometric, high-performance liquid chromatography, electrophoresis, and radiochemistry. Application of the test method for screening the ACE inhibitors activity and investigation of active compounds from natural products can be done easily with this method, it is very helpful in research because the results obtained are simple, accurate, and rapid. PMID:28503045

Simultaneous use of in silico design and a correlated mutation network as a tool to efficiently guide enzyme engineering.

PubMed

Nobili, Alberto; Tao, Yifeng; Pavlidis, Ioannis V; van den Bergh, Tom; Joosten, Henk-Jan; Tan, Tianwei; Bornscheuer, Uwe T

2015-03-23

In order to improve the efficiency of directed evolution experiments, in silico multiple-substrate clustering was combined with an analysis of the variability of natural enzymes within a protein superfamily. This was applied to a Pseudomonas fluorescens esterase (PFE I) targeting the enantioselective hydrolysis of 3-phenylbutyric acid esters. Data reported in the literature for nine substrates were used for the clustering meta-analysis of the docking conformations in wild-type PFE I, and this highlighted a tryptophan residue (W28) as an interesting target. Exploration of the most frequently, naturally occurring amino acids at this position suggested that the reduced flexibility observed in the case of the W28F variant leads to enhancement of the enantioselectivity. This mutant was subsequently combined with mutations identified in a library based on analysis of a correlated mutation network. By interrogation of <80 variants a mutant with 15-fold improved enantioselectivity was found. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functional consequences and rescue potential of pathogenic missense mutations in tripeptidyl peptidase I.

PubMed

Walus, Mariusz; Kida, Elizabeth; Golabek, Adam A

2010-06-01

There are 35 missense mutations among 68 different mutations in the TPP1 gene, which encodes tripeptidyl peptidase I (TPPI), a lysosomal aminopeptidase associated with classic late-infantile neuronal ceroid lipofuscinosis (CLN2 disease). To elucidate the molecular mechanisms underlying TPPI deficiency in patients carrying missense mutations and to test the amenability of mutant proteins to chemical chaperones and permissive temperature treatment, we introduced individually 14 disease-associated missense mutations into human TPP1 cDNA and analyzed the cell biology of these TPPI variants expressed in Chinese hamster ovary cells. Most TPPI variants displayed obstructed transport to the lysosomes, prolonged half-life of the proenzyme, and residual or no enzymatic activity, indicating folding abnormalities. Protein misfolding was produced by mutations located in both the prosegment (p.Gly77Arg) and throughout the length of the mature enzyme. However, the routes of removal of misfolded proteins by the cells varied, ranging from their efficient degradation by the ubiquitin/proteasome system to abundant secretion. Two TPPI variants demonstrated enhanced processing in response to folding improvement treatment, and the activity of one of them, p.Arg447His, showed a fivefold increase under permissive temperature conditions, which suggests that folding improvement strategies may ameliorate the function of some misfolding TPPI mutant proteins.

Glucose-6-phosphate dehydrogenase Buenos Aires: a novel de novo missense mutation associated with severe enzyme deficiency.

PubMed

Minucci, Angelo; Concolino, Paola; Vendittelli, Francesca; Giardina, Bruno; Zuppi, Cecilia; Capoluongo, Ettore

2008-06-01

: Glucose 6-phosphate dehydrogenase (G6PD) catalyzes the first committed steps in the pentose phosphate pathway: the generation of NADPH by this enzyme is essential for protection against oxidative stress. The human enzyme is in a dimer<-->tetramer equilibrium and its stability depends on NADP(+) concentration. Herein, we report a case of a symptomatic baby affected by severe deficiency of G6PD activity due to a novel de novo genetic mutation (g1465C>T) in the thirteenth exon of its gene. : Clinical, biochemical and genetic evaluations of the affected baby and his mother were performed. : We found the g1465C>T novel mutation, in the thirteenth exon of G6PD gene (named "G6PD Buenos Aires variant"). This g1465C>T mutation produce a P489S substitution at protein level. The P489S mutation was absent in his mother, suggesting that G6PD Buenos Aires resulted from a de novo mutation. : The absence of mosaicism in the baby's DNA (from saliva and blood samples) suggests that a de novo mutation event may occur in the very early stages in embryogenesis or in the mother's germ cell lines.

Multiple Mutations Modulate the Function of Dihydrofolate Reductase in Trimethoprim-Resistant Streptococcus pneumoniae

PubMed Central

Maskell, Jeffrey P.; Sefton, Armine M.; Hall, Lucinda M. C.

2001-01-01

Trimethoprim resistance in Streptococcus pneumoniae can be conferred by a single amino acid substitution (I100-L) in dihydrofolate reductase (DHFR), but resistant clinical isolates usually carry multiple DHFR mutations. DHFR genes from five trimethoprim-resistant isolates from the United Kingdom were compared to susceptible isolates and used to transform a susceptible control strain (CP1015). All trimethoprim-resistant isolates and transformants contained the I100-L mutation. The properties of DHFRs from transformants with different combinations of mutations were compared. In a transformant with only the I100-L mutation (R12/T2) and a D92-A mutation also found in the DHFRs of susceptible isolates, the enzyme was much more resistant to trimethoprim inhibition (50% inhibitory concentration [IC50], 4.2 μM) than was the DHFR from strain CP1015 (IC50, 0.09 μM). However, Km values indicated a lower affinity for the enzyme's natural substrates (Km for dihydrofolate [DHF], 3.1 μM for CP1015 and 27.5 μM for R12/T2) and a twofold decrease in the specificity constant. In transformants with additional mutations in the C-terminal portion of the enzyme, Km values for DHF were reduced (9.2 to 15.2 μM), indicating compensation for the lower affinity generated by I100-L. Additional mutations in the N-terminal portion of the enzyme were associated with up to threefold-increased resistance to trimethoprim (IC50 of up to 13.7 μM). It is postulated that carriage of the mutation M53-I—which, like I100-L, corresponds to a trimethoprim binding site in the Escherichia coli DHFR—is responsible for this increase. This study demonstrates that although the I100-L mutation alone may give rise to trimethoprim resistance, additional mutations serve to enhance resistance and modulate the effects of existing mutations on the affinity of DHFR for its natural substrates. PMID:11257022

Angiotensin-converting enzyme activity in Cavalier King Charles Spaniels with an ACE gene polymorphism and myxomatous mitral valve disease.

PubMed

Meurs, Kathryn M; Olsen, Lisbeth H; Reimann, Maria J; Keene, Bruce W; Atkins, Clarke E; Adin, Darcy; Aona, Brent; Condit, Julia; DeFrancesco, Teresa; Reina-Doreste, Yamir; Stern, Joshua A; Tou, Sandra; Ward, Jessica; Woodruff, Kathleen

2018-02-01

Myxomatous mitral valve disease (MMVD) is the most common heart disease in the dog. It is particularly common in the Cavalier King Charles Spaniel (CKCS) breed and affected dogs are frequently managed with angiotensin-converting enzyme inhibitors (ACE-I). We have previously identified a canine ACE gene polymorphism associated with a decrease in angiotensin-converting enzyme (ACE) activity. The aim of this study was to evaluate for the prevalence of the ACE polymorphism in CKCS with mitral valve disease and to determine whether the presence of the polymorphism is associated with alterations in ACE activity at different stages of cardiac disease. Seventy-three dogs with a diagnosis of mitral valve disease were evaluated and a blood sample was drawn for ACE polymorphism genotyping and ACE activity measurement. Forty-three dogs were homozygous for the ACE polymorphism; five were heterozygous and 25 were homozygous wild type. The mean age and the median severity of disease were not different for dogs with the polymorphism and dogs with the wild-type sequence. The median baseline ACE activity was significantly lower for the ACE polymorphism (27.0 U/l) than the wild-type sequence dogs (31.0 U/l) (P=0.02). Dogs with more severe disease and the ACE polymorphism had significantly lower levels of ACE activity than dogs with the wild-type sequence (P=0.03). The CKCS appears to have a high prevalence of the ACE variant. Dogs with the ACE variant had lower levels of ACE activity even in more advanced mitral valve disease than dogs without the variant. The clinical significance of this finding and its impact on the need for ACE-I in dogs with the polymorphism and heart disease deserves further study.

Angiotensin-converting enzyme inhibition improves cardiac fatty acid metabolism in patients with congestive heart failure.

PubMed

Yamauchi, S; Takeishi, Y; Minamihaba, O; Arimoto, T; Hirono, O; Takahashi, H; Miyamoto, T; Nitobe, J; Nozaki, N; Tachibana, H; Watanabe, T; Fukui, A; Kubota, I

2003-08-01

This study aimed to examine whether angiotensin-converting enzyme (ACE) inhibition improved cardiac fatty acid metabolism in patients with congestive heart failure (CHF). Myocardial 123I-beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP) imaging was performed in 25 patients with CHF and in 10 control subjects. Myocardial 123I-BMIPP images were obtained 30 min and 4 h after tracer injection. The heart-to-mediastinum (H/M) ratio of 123I-BMIPP uptake and the washout rate of 123I-BMIPP from the myocardium were calculated. Patients were given enalapril for 6 months, and 123I-BMIPP imaging was repeated. H/M ratios on early and delayed images were lower in CHF patients than in normal controls (P<0.01). The washout rate of 123I-BMIPP from the myocardium was faster in CHF patients than in controls (P<0.01). As the severity of the New York Heart Association (NYHA) functional class increased, the H/M ratio decreased and the washout rate increased. The washout rate of 123I-BMIPP was inversely correlated with left ventricular fractional shortening (R=-0.62, P<0.01). ACE inhibition with enalapril increased the H/M ratio on delayed images (P<0.05) and reduced the washout rate of 123I-BMIPP (P<0.05) in CHF patients. These data suggest that: (1) angiotensin II-mediated intracellular signalling activation may be a possible mechanism for the decreased myocardial uptake and enhanced washout of 123I-BMIPP in heart failure patients; and (2) the improvement in fatty acid metabolism by ACE inhibition may represent a new mechanism for the beneficial effect of this therapy in heart failure.

Cancer-associated IDH1 mutations produce 2-hydroxyglutarate

PubMed Central

Dang, Lenny; White, David W.; Gross, Stefan; Bennett, Bryson D.; Bittinger, Mark A.; Driggers, Edward M.; Fantin, Valeria R.; Jang, Hyun Gyung; Jin, Shengfang; Keenan, Marie C.; Marks, Kevin M.; Prins, Robert M.; Ward, Patrick S.; Yen, Katharine E.; Liau, Linda M.; Rabinowitz, Joshua D.; Cantley, Lewis C.; Thompson, Craig B.; Vander Heiden, Matthew G.; Su, Shinsan M.

2009-01-01

Summary Mutations in the enzyme cytosolic isocitrate dehydrogenase 1 (IDH1) are a common feature of a major subset of primary human brain cancers. These mutations occur at a single amino acid residue of the IDH1 active site resulting in loss of the enzyme’s ability to catalyze conversion of isocitrate to α-ketoglutarate. However, only a single copy of the gene is mutated in tumors, raising the possibility that the mutations do not result in a simple loss of function. Here we show that cancer-associated IDH1 mutations result in a new ability of the enzyme to catalyze the NADPH-dependent reduction of α-ketoglutarate to R(−)-2-hydroxyglutarate (2HG). Structural studies demonstrate that when R132 is mutated to histidine, residues in the active site are shifted to produce structural changes consistent with reduced oxidative decarboxylation of isocitrate and acquisition of the ability to convert α-ketoglutarate to 2HG. Excess accumulation of 2HG has been shown to lead to an elevated risk of malignant brain tumors in patients with inborn errors of 2HG metabolism. Similarly, in human malignant gliomas harboring IDH1 mutations, we find dramatically elevated levels of 2HG. These data demonstrate that the IDH1 mutations result in production of the onco-metabolite 2HG, and suggest that the excess 2HG which accumulates in vivo contributes to the formation and malignant progression of gliomas. PMID:19935646

Common genetic variations of the renin-angiotensin-aldosterone system and response to acute angiotensin I-converting enzyme inhibition in essential hypertension.

PubMed

Hannila-Handelberg, Tuula; Kontula, Kimmo K; Paukku, Kirsi; Lehtonen, Jukka Y; Virtamo, Jarmo; Tikkanen, Ilkka; Hiltunen, Timo P

2010-04-01

In order to get insight into possible genetic determinants of antihypertensive drug action, we analysed the relations between polymorphisms of the genes of the renin-angiotensin-aldosterone system and acute effects of ACE inhibition on blood pressure as well as circulating renin and aldosterone levels in hypertensive patients. A total of 315 hypertensive patients referred for problems in drug treatment were given a single 50 mg dose of captopril. Plasma renin and aldosterone were measured before and 60 min after the drug administration. Four DNA variants, including angiotensin type I receptor (AGTR1) 1166 A/C, angiotensin-converting enzyme (ACE) I/D, angiotensinogen (AGT) M235T and AGT -217 G/A, were genotyped in the patients and normotensive men (n = 175). A replication study on the relation between AGTR1 1166 A/C and plasma renin and aldosterone levels was carried out in the 244 hypertensive men of the pharmacogenetic GENRES Study. Referred hypertensive patients with the AGTR1 CC genotype had higher aldosterone at baseline (P = 0.02) and after 60 min of captopril administration (P = 0.01) compared with the AA genotype. Replicate analysis in the GENRES patients showed a similar trend. When the two studies were combined (315 and 244 patients, respectively), plasma aldosterone level (P = 0.007) as well as aldosterone/renin ratio (P = 0.04) were significantly higher in the CC genotype (n = 13) than in the AA genotype (n = 370). Transfection studies in cultured HEK293 cells indicated that the 1166C allele was associated with higher mRNA levels than the 1166A allele. The AGTR1 1166C allele when present in homozygous form may be associated with a form of essential hypertension characterized by high plasma aldosterone and low plasma renin levels, possibly due to increased AGTR1 mRNA levels and augmented angiotensin II action.

Mutation for nonsyndromic mental retardation in the trans-2-enoyl-CoA reductase TER gene involved in fatty acid elongation impairs the enzyme activity and stability, leading to change in sphingolipid profile.

PubMed

Abe, Kensuke; Ohno, Yusuke; Sassa, Takayuki; Taguchi, Ryo; Çalışkan, Minal; Ober, Carole; Kihara, Akio

2013-12-20

Very long-chain fatty acids (VLCFAs, chain length >C20) exist in tissues throughout the body and are synthesized by repetition of the fatty acid (FA) elongation cycle composed of four successive enzymatic reactions. In mammals, the TER gene is the only gene encoding trans-2-enoyl-CoA reductase, which catalyzes the fourth reaction in the FA elongation cycle. The TER P182L mutation is the pathogenic mutation for nonsyndromic mental retardation. This mutation substitutes a leucine for a proline residue at amino acid 182 in the TER enzyme. Currently, the mechanism by which the TER P182L mutation causes nonsyndromic mental retardation is unknown. To understand the effect of this mutation on the TER enzyme and VLCFA synthesis, we have biochemically characterized the TER P182L mutant enzyme using yeast and mammalian cells transfected with the TER P182L mutant gene and analyzed the FA elongation cycle in the B-lymphoblastoid cell line with the homozygous TER P182L mutation (TER(P182L/P182L) B-lymphoblastoid cell line). We have found that TER P182L mutant enzyme exhibits reduced trans-2-enoyl-CoA reductase activity and protein stability, thereby impairing VLCFA synthesis and, in turn, altering the sphingolipid profile (i.e. decreased level of C24 sphingomyelin and C24 ceramide) in the TER(P182L/P182L) B-lymphoblastoid cell line. We have also found that in addition to the TER enzyme-catalyzed fourth reaction, the third reaction in the FA elongation cycle is affected by the TER P182L mutation. These findings provide new insight into the biochemical defects associated with this genetic mutation.

Peptides derived from Rhopilema esculentum hydrolysate exhibit angiotensin converting enzyme (ACE) inhibitory and antioxidant abilities.

PubMed

Li, Jun; Li, Qian; Li, Jingyun; Zhou, Bei

2014-09-02

Jellyfish (Rhopilema esculentum) was hydrolyzed using alcalase, and two peptides with angiotensin-I-converting enzyme (ACE) inhibitory and antioxidant activities were purified by ultrafiltration and consecutive chromatographic methods. The amino acid sequences of the two peptides were identified as VKP (342 Da) and VKCFR (651 Da) by electrospray ionization tandem mass spectrometry. The IC50 values of ACE inhibitory activities of the two peptides were 1.3 μM and 34.5 μM, respectively. Molecular docking results suggested that VKP and VKCFR bind to ACE through coordinating with the active site Zn(II) atom. Free radical scavenging activity and protection against hydrogen peroxide (H2O2)-induced rat cerebral microvascular endothelial cell (RCMEC) injury were used to evaluate the antioxidant activities of the two peptides. As the results clearly showed that the peptides increased the superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-px) activities in RCMEC cells), it is proposed that the R. esculentum peptides exert significant antioxidant effects.

Fermentation characteristics and angiotensin I-converting enzyme-inhibitory activity of Lactobacillus helveticus isolate H9 in cow milk, soy milk, and mare milk.

PubMed

Wang, Jicheng; Li, Changkun; Xue, Jiangang; Yang, Jie; Zhang, Qing; Zhang, Heping; Chen, Yongfu

2015-06-01

Lactobacillus helveticus isolate H9 demonstrated high angiotensin I-converting enzyme (ACE)-inhibitory activity in previous research. Here, we evaluated the fermentation characteristics (pH, titratable acidity, free amino nitrogen, and viable bacterial counts), ACE-inhibitory activity, and contents of Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) peptides of stored yogurt (4°C for 28 d) fermented by L. helveticus isolate H9 (initially inoculated at 4 concentrations), from cow, mare, and soy milks. During storage, the pH and titratable acidity remained stable in yogurts produced from all milk types and all inoculation concentrations. The viable bacterial counts in all stored yogurts ranged between 10(6.72) and 10(8.59) cfu/g. The highest ACE-inhibitory activity (70.9-74.5%) was achieved at inoculation concentrations of 5×10(6) cfu/mL. The ACE-inhibitory tripeptides VPP and IPP as determined by ultra-performance liquid chromatography-tandem mass spectrometry were not produced in yogurt made from soy milk or mare milk. These evaluations indicate that L. helveticus H9 has good probiotic properties and would be a promising candidate for production of fermented food with probiotic properties. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Angiotensin converting enzyme (ACE) and neprilysin hydrolyze neuropeptides: a brief history, the beginning and follow-ups to early studies.

PubMed

Skidgel, Randal A; Erdös, Ervin G

2004-03-01

Our investigations started when synthetic bradykinin became available and we could characterize two enzymes that cleaved it: kininase I or plasma carboxypeptidase N and kininase II, a peptidyl dipeptide hydrolase that we later found to be identical with the angiotensin I converting enzyme (ACE). When we noticed that ACE can cleave peptides without a free C-terminal carboxyl group (e.g., with a C-terminal nitrobenzylamine), we investigated inactivation of substance P, which has a C-terminal Met(11)-NH(2). The studies were extended to the hydrolysis of the neuropeptide, neurotensin and to compare hydrolysis of the same peptides by neprilysin (neutral endopeptidase 24.11, CD10, NEP). Our publication in 1984 dealt with ACE and NEP purified to homogeneity from human kidney. NEP cleaved substance P (SP) at Gln(6)-Phe(7), Phe(7)[see text]-Phe(8), and Gly(9)-Leu(10) and neurotensin (NT) at Pro(10)-Tyr(11) and Tyr(11)-Ile(12). Purified ACE also rapidly inactivated SP as measured in bioassay. HPLC analysis showed that ACE cleaved SP at Phe(8)-Gly(9) and Gly(9)-Leu(10) to release C-terminal tri- and dipeptide (ratio = 4:1). The hydrolysis was Cl(-) dependent and inhibited by captopril. ACE released only dipeptide from SP free acid. ACE hydrolyzed NT at Tyr(11)-Ile(12) to release Ile(12)-Leu(13). Then peptide substrates were used to inhibit ACE hydrolyzing Fa-Phe-Gly-Gly and NEP cleaving Leu(5)-enkephalin. The K(i) values in microM were as follows: for ACE, bradykinin = 0.4, angiotensin I = 4, SP = 25, SP free acid = 2, NT = 14, and Met(5)-enkephalin = 450, and for NEP, bradykinin = 162, angiotensin I = 36, SP = 190, NT = 39, Met(5)-enkephalin = 22. These studies showed that ACE and NEP, two enzymes widely distributed in the body, are involved in the metabolism of SP and NT. Below we briefly survey how NEP and ACE in two decades have gained the reputation as very important factors in health and disease. This is due to the discovery of more endogenous substrates of the enzymes

The Effects of Angiotensin Converting Enzyme Inhibitors (ACE-I) on Human N-Acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) Levels: A Systematic Review and Meta-Analysis.

PubMed

Mnguni, Ayanda Trevor; Engel, Mark E; Borkum, Megan S; Mayosi, Bongani M

2015-01-01

Tuberculous pericardial effusion is a pro-fibrotic condition that is complicated by constrictive pericarditis in 4% to 8% of cases. N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a ubiquitous tetrapeptide with anti-fibrotic properties that is low in tuberculous pericardial effusion, thus providing a potential mechanism for the heightened fibrotic state. Angiotensin-converting enzyme inhibitors (ACE-I), which increase Ac-SDKP levels with anti-fibrotic effects in animal models, are candidate drugs for preventing constrictive pericarditis if they can be shown to have similar effects on Ac-SDKP and fibrosis in human tissues. To systematically review the effects of ACE-Is on Ac-SDKP levels in human tissues. We searched five electronic databases (1996 to 2014) and conference abstracts with no language restrictions. Two reviewers independently selected studies, extracted data and assessed methodological quality. The protocol was registered in PROSPERO. Four studies with a total of 206 participants met the inclusion criteria. Three studies (106 participants) assessed the change in plasma levels of Ac-SDKP following ACE-I administration in healthy humans. The administration of an ACE-I was associated with an increase in Ac-SDKP levels (mean difference (MD) 5.07 pmol/ml (95% confidence intervals (CI) 0.64 pmol/ml to 9.51 pmol/ml)). Two studies with 100 participants further assessed the change in Ac-SDKP level in humans with renal failure using ACE-I. The administration of an ACE-I was associated with a significant increase in Ac-SDKP levels (MD 8.94 pmol/ml; 95% CI 2.55 to 15.33; I2 = 44%). ACE-I increased Ac-SDKP levels in human plasma. These findings provide the rationale for testing the impact of ACE-I on Ac-SDKP levels and fibrosis in tuberculous pericarditis.

Primary Systemic Amyloidosis and High Levels of Angiotensin-Converting Enzyme: Two Case Reports

PubMed Central

Praena-Segovia, J.; Sanchez-Gastaldo, A.; Bernabeu-Wittel, M.; Ocete-Pérez, R.; Ávila-Polo, R.; Martino, M. L.

2013-01-01

Infiltrative heart diseases are caused by a heterogeneous group of disorders; amyloidosis and sarcoidosis are two frequent causes of myocardial infiltration, which differ in clinical and biological outcome and treatment issues. The presence of high levels of angiotensin-converting enzyme (ACE) in a patient with infiltrative heart disease may increase suspicion of sarcoidosis. Nevertheless, no mention about increased ACE levels in extracerebral primary systemic amyloidosis is available. We present two cases of primary systemic amyloidosis, which are cardiac involvement and elevated ACE levels. PMID:24826302

Angiotensin II-producing enzyme III from acidified serum of nephrectomized dogs.

PubMed

Haas, E; Lewis, L; Koshy, T J; Varde, A U; Renerts, L; Bagai, R C

1989-09-01

A highly active angiotensin-producing enzyme (enzyme III) was obtained from the serum of bilaterally nephrectomized dogs by acid treatment and ammonium sulfate fractionation. An inactive precursor (proenzyme III) was converted to enzyme III during prolonged storage (or by treatment with acid or with cathepsin G or by incubation at 38 degrees C as described in the following paper). Enzyme III reacted maximally at pH 7.7 and it produced up to 400 ng of angiotensin II/mL serum/h (i.e., amounts 4000 times higher than that generated by the endogenous renin present in serum after bilateral nephrectomy). Enzyme III produced angiotensin II at identical rates when either dog angiotensinogen or angiotensin I was used as substrate, but the rate was 710 times higher with synthetic tetradecapeptide renin substrate. Enzyme III is not identical to renin, cathepsin G, tonin, enzyme I, enzyme II, the calcium-dependent angiotensin I-converting enzyme, or the calcium-independent carboxy peptidase, which acts by sequential cleavage of angiotensin I. Enzyme III was inhibited by alpha-1-antitrypsin, diisopropyl fluorophosphate, and lima bean trypsin inhibitor (hence it is a serine proteinase). It was not inhibited by Captopril, Teprotide, or Enalapril. It had been reported previously that cathepsin G released from neutrophil granulocytes, by producing high local concentrations of angiotensin II, may provide a mobile means for modulating blood flow in tissue microvasculature during the inflammatory response. The present study offers a new, additional pathway, by enzyme III, for a similar rapid formation of angiotensin II from serum protein substrate or angiotensin I.

Angiotensin-converting enzyme gene insertion/deletion polymorphism studies in Asian Indian pregnant women biochemically identifies gestational diabetes mellitus.

PubMed

Khan, Imran A; Jahan, Parveen; Hasan, Qurratulain; Rao, Pragna

2014-12-01

Gestational diabetes mellitus (GDM) is defined as glucose intolerance first recognized during pregnancy. Insertion/deletion (I/D) polymorphism of a 287 bp Alu repetitive sequence in intron 16 of the angiotensin-converting enzyme (ACE) gene has been widely investigated in Asian Indian populations with different ethnic origins. The present study examined possible association between I/D polymorphism of the ACE gene and GDM in Asian Indian pregnant women. A total of 200 pregnant women (100 GDM and 100 non-GDM) were recruited in this study and I/D polymorphism of a 287 bp Alu1 element inside intron 16 of the ACE gene was examined by polymerase chain reaction (PCR)-based gel electrophoresis. The distribution of the variants like II, ID, and DD genotypes of ACE gene showed differences between normal GDM versus non-GDM subjects, and the frequency of the ID+ DD Vs II genotype was significant (p=0.0002) in the GDM group. ACE gene polymorphism was associated with GDM in Asian Indian pregnant women. © The Author(s) 2013.

Rapid identification of a novel complex I MT-ND3 m.10134C>A mutation in a Leigh syndrome patient.

PubMed

Miller, David K; Menezes, Minal J; Simons, Cas; Riley, Lisa G; Cooper, Sandra T; Grimmond, Sean M; Thorburn, David R; Christodoulou, John; Taft, Ryan J

2014-01-01

Leigh syndrome (LS) is a rare progressive multi-system neurodegenerative disorder, the genetics of which is frequently difficult to resolve. Rapid determination of the genetic etiology of LS in a 5-year-old girl facilitated inclusion in Edison Pharmaceutical's phase 2B clinical trial of EPI-743. SNP-arrays and high-coverage whole exome sequencing were performed on the proband, both parents and three unaffected siblings. Subsequent multi-tissue targeted high-depth mitochondrial sequencing was performed using custom long-range PCR amplicons. Tissue-specific mutant load was also assessed by qPCR. Complex I was interrogated by spectrophotometric enzyme assays and Western Blot. No putatively causal mutations were identified in nuclear-encoded genes. Analysis of low-coverage off-target mitochondrial reads revealed a previously unreported mitochondrial mutation in the proband in MT-ND3 (m.10134C>A, p.Q26K), a Complex I mitochondrial gene previously associated with LS. Targeted investigations demonstrated that this mutation was 1% heteroplasmic in the mother's blood and homoplasmic in the proband's blood, fibroblasts, liver and muscle. Enzyme assays revealed decreased Complex I activity. The identification of this novel LS MT-ND3 variant, the genomics of which was accomplished in less than 3.5 weeks, indicates that rapid genomic approaches may prove useful in time-sensitive cases with an unresolved genetic diagnosis.

Angiotensin-converting enzyme gene polymorphism predicts the time-course of blood pressure response to angiotensin converting enzyme inhibition in the AASK trial

PubMed Central

Bhatnagar, Vibha; O’Connor, Daniel T.; Schork, Nicholas J.; Salem, Rany M.; Nievergelt, Caroline M.; Rana, Brinda K.; Smith, Douglas W.; Bakris, George L.; Middleton, John P.; Norris, Keith C.; Wright, Jackson T.; Cheek, Deanna; Hiremath, Leena; Contreras, Gabriel; Appel, Lawrence J.; Lipkowitz, Michael S.

2009-01-01

Objective It has yet to be determined whether genotyping at the angiotensin-converting enzyme (ACE) locus is predictive of blood pressure response to an ACE inhibitor. Methods Participants from the African American Study of Kidney Disease and Hypertension trial randomized to the ACE inhibitor ramipril (n = 347) were genotyped at three polymorphisms on ACE, just downstream from the ACE insertion/deletion polymorphism (Ins/Del): G12269A, C17888T, and G20037A. Time to reach target mean arterial pressure (≤ 107 mmHg) was analyzed by genotype and ACE haplotype using Kaplan–Meier survival curves and Cox proportional hazard models. Results Individuals with a homozygous genotype at G12269A responded significantly faster than those with a heterozygous genotype; the adjusted (average number of medications and baseline mean arterial pressure) hazard ratio (homozygous compared to heterozygous genotype) was 1.86 (95% confidence limits 1.32–3.23; P < 0.001 for G12269A genotype). The adjusted hazard ratio for participants with homozygous ACE haplotypes compared to those heterozygous ACE haplotypes was 1.40 (1.13–1.75; P = 0.003 for haplotype). The ACE genotype effects were specific for ACE inhibition (i.e., not seen among those randomized to a calcium channel blocker), and were independent of population stratification. Conclusions African-Americans with a homozygous genotype at G12269A or homozygous ACE haplotypes responded to ramipril significantly faster than those with a heterozygous genotype or heterozygous haplotypes, suggesting that heterosis may be an important determinant of responsiveness to an ACE inhibitor. These associations may be a result of biological activity of this polymorphism, or of linkage disequilibrium with nearby variants such as the ACE Ins/Del, perhaps in the regulation of ACE splicing. PMID:17885551

iMARS--mutation analysis reporting software: an analysis of spontaneous cII mutation spectra.

PubMed

Morgan, Claire; Lewis, Paul D

2006-01-31

The sensitivity of any mutational assay is determined by the level at which spontaneous mutations occur in the corresponding untreated controls. Establishing the type and frequency at which mutations occur naturally within a test system is essential if one is to draw scientifically sound conclusions regarding chemically induced mutations. Currently, mutation-spectra analysis is laborious and time-consuming. Thus, we have developed iMARS, a comprehensive mutation-spectrum analysis package that utilises routinely used methodologies and visualisation tools. To demonstrate the use and capabilities of iMARS, we have analysed the distribution, types and sequence context of spontaneous base substitutions derived from the cII gene mutation assay in transgenic animals. Analysis of spontaneous mutation spectra revealed variation both within and between the transgenic rodent test systems Big Blue Mouse, MutaMouse and Big Blue Rat. The most common spontaneous base substitutions were G:C-->A:T transitions and G:C-->T:A transversions. All Big Blue Mouse spectra were significantly different from each other by distribution and nearly all by mutation type, whereas the converse was true for the other test systems. Twenty-eight mutation hotspots were observed across all spectra generally occurring in CG, GA/TC, GG and GC dinucleotides. A mutation hotspot at nucleotide 212 occurred at a higher frequency in MutaMouse and Big Blue Rat. In addition, CG dinucleotides were the most mutable in all spectra except two Big Blue Mouse spectra. Thus, spontaneous base-substitution spectra showed more variation in distribution, type and sequence context in Big Blue Mouse relative to spectra derived from MutaMouse and Big Blue Rat. The results of our analysis provide a baseline reference for mutation studies utilising the cII gene in transgenic rodent models. The potential differences in spontaneous base-substitution spectra should be considered when making comparisons between these test systems

A molecular chaperone for mitochondrial complex I assembly is mutated in a progressive encephalopathy

PubMed Central

Ogilvie, Isla; Kennaway, Nancy G.; Shoubridge, Eric A.

2005-01-01

NADH:ubiquinone oxidoreductase (complex I) deficiency is a common cause of mitochondrial oxidative phosphorylation disease. It is associated with a wide range of clinical phenotypes in infants, including Leigh syndrome, cardiomyopathy, and encephalomyopathy. In at least half of patients, enzyme deficiency results from a failure to assemble the holoenzyme complex; however, the molecular chaperones required for assembly of the mammalian enzyme remain unknown. Using whole genome subtraction of yeasts with and without a complex I to generate candidate assembly factors, we identified a paralogue (B17.2L) of the B17.2 structural subunit. We found a null mutation in B17.2L in a patient with a progressive encephalopathy and showed that the associated complex I assembly defect could be completely rescued by retroviral expression of B17.2L in patient fibroblasts. An anti-B17.2L antibody did not associate with the holoenzyme complex but specifically recognized an 830-kDa subassembly in several patients with complex I assembly defects and coimmunoprecipitated a subset of complex I structural subunits from normal human heart mitochondria. These results demonstrate that B17.2L is a bona fide molecular chaperone that is essential for the assembly of complex I and for the normal function of the nervous system. PMID:16200211

Angiotensin-Converting Enzyme (ACE) I/D and Alpha-Adducin (ADD1) G460W Gene Polymorphisms in Turkish Patients with Severe Chronic Tinnitus.

PubMed

Yuce, Salim; Sancakdar, Enver; Bağcı, Gokhan; Koc, Sema; Kurtulgan, Hande Kucuk; Bağcı, Binnur; Doğan, Mansur; Uysal, İsmail Onder

2016-04-01

Tinnitus is described as a disturbing sound sensation in the absence of external stimulation. We aimed to investigate whether there is any relationship between severe chronic tinnitus and angiotensin-converting enzyme (ACE) I/D and α-adducin (ADD1) G460W gene polymorphisms. The patient group and control group consisted of 89 and 104 individuals, respectively. The evaluation of tinnitus was performed using the Strukturiertes Tinnitus-Interview (STI). The Tinnitus Handicap Inventory (THI) was used to evaluate the tinnitus severity. Polymerase chain reaction (PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were used for genotyping. With regard to the ACE I/D polymorphism, there was no significant difference in genotype and allele frequencies between the patient group and control group. However, a statistically significant difference was found in genotype (p<0.01) and allele frequencies (p=0.021) of the ADD1 G460W gene polymorphism. Combined genotype analysis showed that the ACE II /ADD1 GW genotype was statistically significantly higher in the patient group than in the control group (X2: 7.15, p=0.007). The odds ratio value of the GW genotype was 2.5 (95% CI=1.4-4.7) (p<0.01). Our results demonstrate an association between ADD1 G460W gene polymorphism and susceptibility to severe chronic tinnitus. It was found that the GW genotype increased the disease risk by 2.5-fold compared with other genotypes. This indicates that ADD1 G460W polymorphism could be an important factor in the pathophysiology of tinnitus.

The Angiotensin Converting Enzyme Insertion/Deletion Polymorphism Modifies Exercise-Induced Muscle Metabolism

PubMed Central

Vaughan, David; Brogioli, Michael; Maier, Thomas; White, Andy; Waldron, Sarah; Rittweger, Jörn; Toigo, Marco; Wettstein, Jessica; Laczko, Endre; Flück, Martin

2016-01-01

Objective A silencer region (I-allele) within intron 16 of the gene for the regulator of vascular perfusion, angiotensin-converting enzyme (ACE), is implicated in phenotypic variation of aerobic fitness and the development of type II diabetes. We hypothesised that the reportedly lower aerobic performance in non-carriers compared to carriers of the ACE I-allele, i.e. ACE-DD vs. ACE-ID/ACE-II genotype, is associated with alterations in activity-induced glucose metabolism and capillarisation in exercise muscle. Methods Fifty-three, not-specifically trained Caucasian men carried out a one-legged bout of cycling exercise to exhaustion and/or participated in a marathon, the aim being to identify and validate genotype effects on exercise metabolism. Respiratory exchange ratio (RER), serum glucose and lipid concentration, glycogen, and metabolite content in vastus lateralis muscle based on ultra-performance lipid chromatography-mass spectrometry (UPLC-MS), were assessed before and after the cycling exercise in thirty-three participants. Serum metabolites were measured in forty subjects that completed the marathon. Genotype effects were assessed post-hoc. Results Cycling exercise reduced muscle glycogen concentration and this tended to be affected by the ACE I-allele (p = 0.09). The ACE-DD genotype showed a lower maximal RER and a selective increase in serum glucose concentration after exercise compared to ACE-ID and ACE-II genotypes (+24% vs. +2% and –3%, respectively). Major metabolites of mitochondrial metabolism (i.e. phosphoenol pyruvate, nicotinamide adenine dinucleotide phosphate, L-Aspartic acid, glutathione) were selectively affected in vastus lateralis muscle by exercise in the ACE-DD genotype. Capillary-to-fibre ratio was 24%-lower in the ACE-DD genotype. Individuals with the ACE-DD genotype demonstrated an abnormal increase in serum glucose to 7.7 mM after the marathon. Conclusion The observations imply a genetically modulated role for ACE in control of

Endotoxin reduces specific pulmonary uptake of radiolabeled monoclonal antibody to angiotensin-converting enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzykantov, V.R.; Puchnina, E.A.; Atochina, E.N.

The biodistribution of radiolabeled monoclonal antibody (Mab) to angiotensin-converting enzyme (ACE) was examined in normal and endotoxin-treated rats. Endotoxin administration at a dose of 4 mg/kg induced mild or middle pulmonary edema. The ACE activity in lung homogenate remained virtually unchanged, while the activity of serum ACE increased 15 hr after endotoxin infusion. In normal rats, anti-ACE Mab accumulates specifically in the lung after i.v. injection. Endotoxin injection induces reduction of specific pulmonary uptake of this antibody. Even in non-edematous endotoxemia, the accumulation of anti-ACE Mab antibody (Mab 9B9) decreased from 19.02 to 11.91% of ID/g of tissue without anymore » change in accumulation of control nonspecific IgG. The antibody distribution in other organs and its blood level were almost the same as in the control. In a case of endotoxemia accompanied by increased microvascular permeability, the lung accumulation of Mab 9B9 was reduced to 9.17% of ID/g of tissue, while the accumulation of nonspecific IgG increased to 1.44% versus 0.89% in the control.« less

Molecular diversity of tuliposide B-converting enzyme in tulip (Tulipa gesneriana): identification of the third isozyme with a distinct expression profile.

PubMed

Nomura, Taiji; Kuchida, Ryo; Kitaoka, Naoki; Kato, Yasuo

2018-02-23

6-Tuliposide B (PosB), a major secondary metabolite that accumulates in tulip (Tulipa gesneriana), is converted to the antibacterial lactone, tulipalin B (PaB), by PosB-converting enzyme (TCEB). TgTCEB1 and TgTCEB-R, which encode TCEB, are specifically expressed in tulip pollen and roots, respectively, but are hardly expressed in other tissues (e.g. leaves) despite the presence of substantial PosB-converting activity, suggesting the existence of another TCEB isozyme. Here, we describe the identification of TgTCEB-L ("L" for leaf), a paralog of TgTCEB1 and TgTCEB-R, from leaves via native enzyme purification. The enzymatic characters of TgTCEB-L, including catalytic activity and subcellular localization, were substantially the same as those of TgTCEB1 and TgTCEB-R. However, TgTCEB-L did not exhibit tissue-specific expression. Identification of TgTCEB-L explains the PosB-converting activity detected in tissues where TgTCEB1 and TgTCEB-R transcripts could not be detected, indicating that tulip subtilizes the three TgTCEB isozymes depending on the tissue.

Association of Angiotensin-Converting Enzyme ACE Gene Polymorphism with ACE Activity and Susceptibility to Vitiligo in Egyptian Population.

PubMed

Badran, Dahlia I; Nada, Hesham; Hassan, Ranya

2015-05-01

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with vitiligo in the Indians and Koreans, but not in those of English or Turkish background. We investigated the ACE (I/D) polymorphism in vitiligo patients for the first time in Egypt and compared serum ACE levels between vitiligo patients and controls. The present study was carried out in 100 vitiligo patients (40 males and 60 females) and in 100 healthy controls of an Egyptian population using the polymerase chain reaction genotyping method. The ACE genotype and allele frequency was significantly different between vitiligo patients and controls. Our results revealed a significant increase in the frequency of the ACE I allele (p=0.002; odds ratio: 1.99; 95% confidence intervals: 1.207-3.284) with an overrepresentation of I/D genotype in the vitiligo patient group. Furthermore, there was a significant difference between the segmental, nonsegmental, and focal vitiligo in ACE gene genotype distribution. Serum ACE levels were significantly increased in vitiligo patients compared to controls (p=0.034). This study suggests that, for the first time, ACE gene polymorphism confers susceptibility to vitiligo in the Egyptian population.

Serum angiotensin-converting enzyme (SACE) in sarcoidosis and other granulomatous disorders.

PubMed

Studdy, P; Bird, R; James, D G

Serum angiotensin-converting enzyme (SACE) activity was significantly higher in 90 patients with sarcoidosis (55 +/- [S.D.] 23 nmol min-1 ml-1) than in 80 healthy controls (34 +/- 9 nmol min-1 ml-1). Steroid therapy modified SACE activity; 60 sarcoidosis patients who were not being treated with steroids had significantly higher enzyme activities (58 +/- 24 nmol min-1 ml-1) than 30 steroid-treated sarcoidosis patients (40 +/- 19 nmol min-1 ml-1). In 50% of the non-steroid treated sarcoidosis patients SACE activity was more than 2 S.D. above the mean value for the controls. SACE activity was measured in 22 tuberculous patients (38 +/- 14 nmol min-1 ml-1), 20 leprosy patients (34 +/- 9 nmol min-1 ml-1), 31 with primary biliary cirrhosis (44 +/- 20 nmol min-1 ml-1), 26 with inflammatory bowel disease (31 +/- 9 nmol min-1 ml-1), 8 with hepatic granulomatous disease, 5 with Hodgkin's disease, and 2 with schistosomiasis. The combined false-positive rate for these non-sarcoidosis patients was 10%. Serial SACE assays provide useful information on the course of sarcoidosis and response to steroid treatment.

Serum angiotensin--converting enzyme (SACE) in sarcoidosis and other granulomatous disorders.

PubMed

Studdy, P; Bird; James, D G; Sherlock, S

Serum angiotensin-converting enzyme (SACE) activity was significantly higher in 90 patients with sarcoidosis (55 +/- [S.D.] 23 nmol min-1 ml-1) than in 80 healthy controls (34 +/- 9 nmol min-1 ml-1). Steroid therapy modified SACE activity; 60 sarcoidosis patients who were not being treated with steroids had significantly higher enzyme activities (58 +/- 24 nmol min-1 ml-1) than 30 steroid-treated sarcoidosis patients (40 +/- 19 nmol min-1 ml-1). In 50% of the non-steroid treated sarcoidosis patients SACE activity was more than than 2 S.D. above the mean value for the controls. SACE activity was measured in 22 tuberculous patients (38 +/- 14 nmol min-1 ml-1), 20 leprosy patients (34 +/- 9 nmol min-1 ml-1), 31 with primary biliary cirrhosis (44 +/- 20 nmol min-1 ml-1), 26 with inflammatory bowel disease (31 +/- 9 nmol min-1 ml-1), eight with hepatic granulomatous disease, five with Hodgkin's disease, and two with schistosomiasis. The combined false-positive rate for these non-sarcoidosis patients was 10%. Serial SACE assays provide useful information on the course of sarcoidosis and response to steroid treatment.

Withholding versus Continuing Angiotensin-converting Enzyme Inhibitors or Angiotensin II Receptor Blockers before Noncardiac Surgery: An Analysis of the Vascular events In noncardiac Surgery patIents cOhort evaluatioN Prospective Cohort.

PubMed

Roshanov, Pavel S; Rochwerg, Bram; Patel, Ameen; Salehian, Omid; Duceppe, Emmanuelle; Belley-Côté, Emilie P; Guyatt, Gordon H; Sessler, Daniel I; Le Manach, Yannick; Borges, Flavia K; Tandon, Vikas; Worster, Andrew; Thompson, Alexandra; Koshy, Mithin; Devereaux, Breagh; Spencer, Frederick A; Sanders, Robert D; Sloan, Erin N; Morley, Erin E; Paul, James; Raymer, Karen E; Punthakee, Zubin; Devereaux, P J

2017-01-01

The effect on cardiovascular outcomes of withholding angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in chronic users before noncardiac surgery is unknown. In this international prospective cohort study, the authors analyzed data from 14,687 patients (including 4,802 angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users) at least 45 yr old who had in-patient noncardiac surgery from 2007 to 2011. Using multivariable regression models, the authors studied the relationship between withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers and a primary composite outcome of all-cause death, stroke, or myocardial injury after noncardiac surgery at 30 days, with intraoperative and postoperative clinically important hypotension as secondary outcomes. Compared to patients who continued their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, the 1,245 (26%) angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users who withheld their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers in the 24 h before surgery were less likely to suffer the primary composite outcome of all-cause death, stroke, or myocardial injury (150/1,245 [12.0%] vs. 459/3,557 [12.9%]; adjusted relative risk, 0.82; 95% CI, 0.70 to 0.96; P = 0.01) and intraoperative hypotension (adjusted relative risk, 0.80; 95% CI, 0.72 to 0.93; P < 0.001). The risk of postoperative hypotension was similar between the two groups (adjusted relative risk, 0.92; 95% CI, 0.77 to 1.10; P = 0.36). Results were consistent across the range of preoperative blood pressures. The practice of withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers was only modestly correlated with patient characteristics and the type and timing of surgery. Withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers before major noncardiac surgery

Overcoming difficulties with caviar formation, desanding of converter I, Leuna, 1941

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1941-01-01

The life of a coal stall was in most cases limited by the grinding action of the solid components of the coal. The so-called caviar produced the greatest amount of difficulties. Its elimination was accomplished by the removal of the coarsest particle from the first converter, the converter 1 desanding. Before desanding was introduced, perforated thermocouple-protecting tubes and catalyst tubes almost ground through were found in almost every dismantling of the stalls. Small-scale and large-scale solutions to this problem were discussed. A sketch of desanding in converter I was given. Another sketch showed the pipe line of the HOLD frommore » the converter to the pressure relief. A screen analysis of the converter I desanding and of the normal HOLD were made to determine the proportion of coarse and fine sludge. Curve A and curve B given on two graphs showed the percent distribution and the actual amount involved. Sheet 1 gave diagrams of the residue and damage by wear in converters 1 and 2 of stall 8. Sheet 4 showed a diagram of converter 1 with an inclined plane for desanding and sheet 8 gave the desanding results from a test on converter 1. The final conclusion drawn was that desanding of converter 1 completely eliminated the formation and settling of caviar in the coal stall converters. The desanding process was one in which about 10% of the sludge in the first converter was periodically withdrawn from the bottom of converter, often to be sent on to be combined with hot oil letdown for further processing. The desanding residue could be readily carbonized because the proportion of asphalt to solids was very good. 8 diagrams« less

Flavor Enhancer From Catfish (Clarias batrachus) Bekasam Powder and Angiotensin-I-Converting Enzyme (ACE) Inhibitory Activity in Various Dishes

NASA Astrophysics Data System (ADS)

Lestari, Yanesti N.; Murwani, Retno; Agustini, Tri W.

2018-02-01

Flavor enhancer is characterized by high glutamic acid content and it can be obtained from fermented food such as Bekasam. Fermented food had inhibitory effect on Angiotensin-I-Converting Enzyme (ACE) activity which is advantageous for hypertension. However, such activity was not known to sustain in food system. The aim of this research was to study addition of flavour enhancer from Catfish Bekasam Powder (CBP) in various food systems and to determine the ACE inhibitory (ACEI) activity in the food system. Four food system consisted of carrot, champignon, and chicken meat dishes were boiled in water and added with CBP or MSG. Each food system was added with graded level of CBP (0%; 0.5%; 0.8%; 1.1%; and 1,4%) and for control monosodium glutamate (MSG) was used. ACEI activity in each food system and organoleptic test using multiple comparison differentiation on 15 semi-trained panellists were determined. The results showed that there were fluctuation of ACEI activity in the carrot, champignon, and chicken meat dishes (p=0.017; 0.043; and 0.032). The MSG containing dishes showed the lowest ACEI activity. Addition of graded level of CBP on carrot, champignon, and chicken meat dishes were directly proportional to glutamic acid content but inversely proportional to ACEI activity (p<0.05). The addition of commercial MSG on all dishes increased glutamic acid content but reduced ACE-inhibitory activity significantly (p<0.05). Comparing CBP to MSG addition in champignon dish revealed that increasing level of CBP increased the flavour preference of the panellists. On the contrary the higher the addition CBP in noodle and chicken meat dishes the worse were the flavour score (p<0.05). It can be concluded that the addition of CBP as flavour enhancer on various dishes can deliver better flavour and ACE-inhibitory activity than the addition of commercial MSG.

Angiotensin-converting enzyme-inhibitory activity in protein hydrolysates from normal and anthracnose disease-damaged Phaseolus vulgaris seeds.

PubMed

Hernández-Álvarez, Alan Javier; Carrasco-Castilla, Janet; Dávila-Ortiz, Gloria; Alaiz, Manuel; Girón-Calle, Julio; Vioque-Peña, Javier; Jacinto-Hernández, Carmen; Jiménez-Martínez, Cristian

2013-03-15

Bean seeds are an inexpensive source of protein. Anthracnose disease caused by the fungus Colletotrichum lindemuthianum results in serious losses in common bean (Phaseolus vulgaris L.) crops worldwide, affecting any above-ground plant part, and protein dysfunction, inducing the synthesis of proteins that allow plants to improve their stress tolerance. The aim of this study was to evaluate the use of beans damaged by anthracnose disease as a source of peptides with angiotensin-converting enzyme (ACE-I)-inhibitory activity. Protein concentrates from beans spoiled by anthracnose disease and from regular beans as controls were prepared by alkaline extraction and precipitation at isolelectric pH and hydrolysed using Alcalase 2.4 L. The hydrolysates from spoiled beans had ACE-I-inhibitory activity (IC(50) 0.0191 mg protein mL(-1)) and were very similar to those from control beans in terms of ACE-I inhibition, peptide electrophoretic profile and kinetics of hydrolysis. Thus preparation of hydrolysates using beans affected by anthracnose disease would allow for revalorisation of this otherwise wasted product. The present results suggest the use of spoiled bean seeds, e.g. anthracnose-damaged beans, as an alternative for the isolation of ACE-I-inhibitory peptides to be further introduced as active ingredients in functional foods. © 2012 Society of Chemical Industry.

DD genotype of angiotensin-converting enzyme in type 2 diabetes mellitus with renal disease in Mexican Mestizos.

PubMed

Palomo-Piñón, Silvia; Gutiérrez-Rodríguez, Margarita E; Díaz-Flores, Margarita; Sánchez-Barrera, Reyna; Valladares-Salgado, Adán; Utrera-Barillas, Dolores; Durán-Reyes, Genoveva; Galván-Duarte, Rosa E; Trinidad-Ramos, Pedro; Cruz, Miguel

2009-04-01

The DD genotype of angiotensin-converting enzyme (ACE) has been suggested as a major contributor of diabetic nephropathy in several populations. The purpose of the present study was to determine whether micro/macroalbuminuria is associated with ACE insertion/deletion (I/D) polymorphism in Mexican Mestizos with type 2 diabetes mellitus. A total of 435 patients with type 2 diabetes mellitus, of whom 233 had albuminuria, were characterized for the ACE I/D polymorphism by the polymerase chain reaction method. Clinical and biochemical characteristics and frequencies according to DD, ID and II genotypes in patients with and without albuminuria showed no significant differences. However, only females with micro/macroalbuminuria showed higher frequency of a DD genotype than those without albuminuria (27.9%, 21.2% and 10.5%, respectively; P

Optimized angiotensin-converting enzyme activity assay for the accurate diagnosis of sarcoidosis.

PubMed

Csongrádi, Alexandra; Enyedi, Attila; Takács, István; Végh, Tamás; Mányiné, Ivetta S; Pólik, Zsófia; Altorjay, István Tibor; Balla, József; Balla, György; Édes, István; Kappelmayer, János; Tóth, Attila; Papp, Zoltán; Fagyas, Miklós

2018-06-27

Serum angiotensin-converting enzyme (ACE) activity determination can aid the early diagnosis of sarcoidosis. We aimed to optimize a fluorescent kinetic assay for ACE activity by screening the confounding effects of endogenous ACE inhibitors and interfering factors. Genotype-dependent and genotype-independent reference values of ACE activity were established, and their diagnostic accuracies were validated in a clinical study. Internally quenched fluorescent substrate, Abz-FRK(Dnp)P-OH was used for ACE-activity measurements. A total of 201 healthy individuals and 59 presumably sarcoidotic patients were enrolled into this study. ACE activity and insertion/deletion (I/D) genotype of the ACE gene were determined. Here we report that serum samples should be diluted at least 35-fold to eliminate the endogenous inhibitor effect of albumin. No significant interferences were detected: up to a triglyceride concentration of 16 mM, a hemoglobin concentration of 0.71 g/L and a bilirubin concentration of 150 μM. Genotype-dependent reference intervals were considered as 3.76-11.25 U/L, 5.22-11.59 U/L, 7.19-14.84 U/L for II, ID and DD genotypes, respectively. I/D genotype-independent reference interval was established as 4.85-13.79 U/L. An ACE activity value was considered positive for sarcoidosis when it exceeded the upper limit of the reference interval. The optimized assay with genotype-dependent reference ranges resulted in 42.5% sensitivity, 100% specificity, 100% positive predictive value and 32.4% negative predictive value in the clinical study, whereas the genotype-independent reference range proved to have inferior diagnostic efficiency. An optimized fluorescent kinetic assay of serum ACE activity combined with ACE I/D genotype determination is an alternative to invasive biopsy for confirming the diagnosis of sarcoidosis in a significant percentage of patients.

Angiotensin-converting enzyme genotype and arterial oxygen saturation at high altitude in Peruvian Quechua.

PubMed

Bigham, Abigail W; Kiyamu, Melisa; León-Velarde, Fabiola; Parra, Esteban J; Rivera-Ch, Maria; Shriver, Mark D; Brutsaert, Tom D

2008-01-01

The I-allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with performance benefits at high altitude (HA). In n = 142 young males and females of largely Quechua origins in Peru, we evaluated 3 specific hypotheses with regard to the HA benefits of the I-allele: (1) the I-allele is associated with higher arterial oxygen saturation (Sa(O(2))) at HA, (2) the I-allele effect depends on the acclimatization state of the subjects, and (3) the putative I-allele effect on Sa(O(2)) is mediated by the isocapnic hypoxic ventilatory response (HVR, l/min(1)/% Sa(O(2))(1)). The subject participants comprised two different study groups including BLA subjects (born at low altitude) who were lifelong sea-level residents transiently exposed to hypobaric hypoxia (<24 h) and BHA subjects (born at HA) who were lifelong residents of HA. To control for the possibility of population stratification, Native American ancestry proportion (NAAP) was estimated as a covariate for each individual using a panel of 70 ancestry-informative molecular markers (AIMS). At HA, resting and exercise Sa(O(2)) was strongly associated with the ACE genotype, p = 0.008 with approximately 4% of the total variance in Sa(O(2)) attributed to ACE genotype. Moreover, I/I individuals maintained approximately 2.3 percentage point higher Sa(O(2)) compared to I/D and D/D. This I-allele effect was evident in both BLA and BHA groups, suggesting that acclimatization state has little influence on the phenotypic expression of the ACE gene. Finally, ACE genotype was not associated with the isocapnic HVR, although HVR had a strong independent effect on Sa(O(2)) (p = 0.001). This suggests that the I-allele effect on Sa(O(2)) is not mediated by the peripheral control of breathing, but rather by some other central cardiopulmonary effect of the ACE gene on the renin-angiotensin-aldosterone system (RAAS).

Response to angiotensin-converting enzyme inhibition is selectively blunted by high sodium in angiotensin-converting enzyme DD genotype: evidence for gene-environment interaction in healthy volunteers.

PubMed

Lely, A Titia; Heerspink, Hiddo J Lambers; Zuurman, Mike; Visser, Folkert W; Kocks, Menno J A; Boomsma, Frans; Navis, Gerjan

2010-12-01

Renin-angiotensin-aldosterone system blockade is a cornerstone in cardiovascular protection. Angiotensin-converting enzyme (ACE)-DD genotype has been associated with resistance to angiotensin-converting enzyme inhibition (ACEi), but data are conflicting. As sodium intake modifies the effect of ACEi as well as the genotype-phenotype relationship, we hypothesize gene-environment interaction between sodium-status, the response to ACEi, and ACE genotype. Thirty-five male volunteers (26 ± 9 years; II n = 6, ID n = 18, DD n = 11) were studied during placebo and ACEi (double blind, enalapril 20 mg/day) on low [7 days 50 mmol Na/day (low salt)] and high [7 days 200 mmol Na/day (high salt)] sodium, with a washout of 6 weeks in-between. After each period mean arterial pressure (MAP) was measured before and during graded infusion of angiotensin II (Ang II). During high salt, ACEi reduced MAP in II and ID, but not in DD [II: 88 (78-94) versus 76 (72-88); ID: 87 (84-91) versus 83 (79-87); both P < 0.05 and DD: 86 (82-96) versus 88 (80-90); ns, P < 0.05 between genotypes]. However, during low salt, ACEi reduced MAP in all genotype groups [II: 83 (78-89) versus 77 (72-83); ID: 88 (84-91) versus 82 (78-86); DD: 84 (80-91) versus 81 (75-85); all P < 0.05]. During high salt + ACEi, the Ang II response was blunted in DD, with an 18% rise in MAP during the highest dose versus 22 and 31% in ID and II (P < 0.05). Low salt annihilated these differences. In healthy participants, the MAP response to ACEi is selectively blunted in DD genotype during high salt, accompanied by blunted sensitivity to Ang II. Low salt corrects both abnormalities. Further analysis of this gene-environment interaction in patients may contribute to strategies for improvement of individual treatment efficacy.

Mucopolysaccharidosis IVA: Identification of a common missense mutation I113F in the N-Acetylgalactosamine-6-sulfate sulfatase gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomatsu, Shunji; Fukuda, Seiji; Rezvi, Maruf

1995-09-01

Mucopolysaccharidosis IVA is an autosomal recessive lysosomal storage disorder caused by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS). The recent isolation and characterization of cDNA and genomic sequences encoding GALNS has facilitated identification of the molecular lesions that cause MPS IVA. We identified a common missense mutation among Caucasian MPS IVA patients. The mutation was originally detected by SSCP, and successive sequencing revealed an A{yields}T transversion at nt 393. This substitution altered the isoleucine at position 113 to phenylalanine (I113F) in the 622 amino acid GALNS protein and was associated with a severe phenotype in a homozygote. Compound heterogzygotes with onemore » I113F-allele mutation have a wide range of clinical phenotypes. Transfection experiments in GALNS-deficient fibroblasts revealed that the mutation drastically reduces the enzyme activity of GALNS. Allele-specific oligonucleotide or SSCP analysis indicated that this mutation accounted for 22.5% (9/40) of unrelated MPS IVA chromosomes from 23 Caucasian patients, including 6 consanguineous cases. Of interest, the I1e 113{yields}Phe substitution occurred in only Caucasian MPS IVA patients and in none of the GALNS alleles of 20 Japanese patients. These findings identify a frequent missense mutation among MPS IVA patients of Caucasian ancestry that results in severe MPS IVA when homoallelic, and will facilitate molecular diagnosis of most such patients and identification of heterozygous carriers. In addition to this common mutation, 10 different point mutations and 2 small deletions were detected, suggesting allelic heterogeneity in GALNS gene. 32 refs., 2 figs., 3 tabs.« less

Synthesis and evaluation of novel triazoles and mannich bases functionalized 1,4-dihydropyridine as angiotensin converting enzyme (ACE) inhibitors.

PubMed

Kumbhare, Ravindra M; Kosurkar, Umesh B; Bagul, Pankaj K; Kanwal, Abhinav; Appalanaidu, K; Dadmal, Tulshiram L; Banerjee, Sanjay Kumar

2014-11-01

A series of novel diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate embedded triazole and mannich bases were synthesized, and evaluated for their angiotensin converting enzyme (ACE) inhibitory activity. Screening of above synthesized compounds for ACE inhibition showed that triazoles functionalized compounds have better ACE inhibitory activity compared to that of mannich bases analogues. Among all triazoles we found 6 h, 6 i and 6 j to have good ACE inhibition activity with IC50 values 0.713 μM, 0.409 μM and 0.653 μM, respectively. Among mannich bases series compounds, only 7c resulted as most active ACE inhibitor with IC50 value of 0.928 μM. Copyright © 2014. Published by Elsevier Ltd.

The angiotensin converting enzyme inhibitor captopril protects nigrostriatal dopamine neurons in animal models of parkinsonism

PubMed Central

Sonsalla, Patricia K.; Coleman, Christal; Wong, Lai-Yoong; Harris, Suzan L.; Richardson, Jason R.; Gadad, Bharathi S.; Li, Wenhao; German, Dwight C.

2013-01-01

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by a prominent loss of nigrostriatal dopamine (DA) neurons with an accompanying neuroinflammation. The peptide angiotensin II (AngII) plays a role in oxidative-stress induced disorders and is thought to mediate its detrimental actions via activation of AngII AT1 receptors. The brain renin-angiotensin system is implicated in neurodegenerative disorders including PD. Blockade of the angiotensin converting enzyme or AT1 receptors provides protection in acute animal models of parkinsonism. We demonstrate here that treatment of mice with the angiotensin converting enzyme inhibitor captopril protects the striatum from acutely administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrine (MPTP), and that chronic captopril protects the nigral DA cell bodies from degeneration in a progressive rat model of parkinsonism created by the chronic intracerebral infusion of 1-methyl-4-phenylpyridinium (MPP+). The accompanying activation of microglia in the substantia nigra of MPP+-treated rats was reduced by the chronic captopril treatment. These findings indicate that captopril is neuroprotective for nigrostriatal DA neurons in both acute and chronic rodent PD models. Targeting the brain AngII pathway may be a feasible approach to slowing neurodegeneration in PD. PMID:24184050

Structure-function studies of BPP-BrachyNH2 and synthetic analogues thereof with Angiotensin I-Converting Enzyme.

PubMed

Arcanjo, Daniel D R; Vasconcelos, Andreanne G; Nascimento, Lucas A; Mafud, Ana Carolina; Plácido, Alexandra; Alves, Michel M M; Delerue-Matos, Cristina; Bemquerer, Marcelo P; Vale, Nuno; Gomes, Paula; Oliveira, Eduardo B; Lima, Francisco C A; Mascarenhas, Yvonne P; Carvalho, Fernando Aécio A; Simonsen, Ulf; Ramos, Ricardo M; Leite, José Roberto S A

2017-10-20

The vasoactive proline-rich oligopeptide termed BPP-BrachyNH 2 (H-WPPPKVSP-NH 2 ) induces in vitro inhibitory activity of angiotensin I-converting enzyme (ACE) in rat blood serum. In the present study, the removal of N-terminal tryptophan or C-terminal proline from BPP-BrachyNH 2 was investigated in order to predict which structural components are important or required for interaction with ACE. Furthermore, the toxicological profile was assessed by in silico prediction and in vitro MTT assay. Two BPP-BrachyNH 2 analogues (des-Trp 1 -BPP-BrachyNH 2 and des-Pro 8 -BPP-BrachyNH 2 ) were synthesized, and in vitro and in silico ACE inhibitory activity and toxicological profile were assessed. The des-Trp 1 -BPP-BrachyNH 2 and des-Pro 8 -BPP-BrachyNH 2 were respectively 3.2- and 29.5-fold less active than the BPP-BrachyNH 2 -induced ACE inhibitory activity. Molecular Dynamic and Molecular Mechanics Poisson-Boltzmann Surface Area simulations (MM-PBSA) demonstrated that the ACE/BBP-BrachyNH 2 complex showed lower binding and van der Wall energies than the ACE/des-Pro 8 -BPP-BrachyNH 2 complex, therefore having better stability. The removal of the N-terminal tryptophan increased the in silico predicted toxicological effects and cytotoxicity when compared with BPP-BrachyNH 2 or des-Pro 8 -BPP-BrachyNH 2 . Otherwise, des-Pro 8 -BPP-BrachyNH 2 was 190-fold less cytotoxic than BPP-BrachyNH 2 . Thus, the removal of C-terminal proline residue was able to markedly decrease both the BPP-BrachyNH 2 -induced ACE inhibitory and cytotoxic effects assessed by in vitro and in silico approaches. In conclusion, the aminoacid sequence of BPP-BrachyNH 2 is essential for its ACE inhibitory activity and associated with an acceptable toxicological profile. The perspective of the interactions of BPP-BrachyNH 2 with ACE found in the present study can be used for development of drugs with differential therapeutic profile than current ACE inhibitors. Copyright © 2017 Elsevier Masson SAS. All

Insights into enzyme point mutation effect by molecular simulation: phenylethylamine oxidation catalyzed by monoamine oxidase A.

PubMed

Oanca, Gabriel; Purg, Miha; Mavri, Janez; Shih, Jean C; Stare, Jernej

2016-05-21

The I335Y point mutation effect on the kinetics of phenylethylamine decomposition catalyzed by monoamine oxidase A was elucidated by means of molecular simulation. The established empirical valence bond methodology was used in conjunction with the free energy perturbation sampling technique and a classical force field representing the state of reactants and products. The methodology allows for the simulation of chemical reactions, in the present case the breaking of the α-C-H bond in a phenylethylamine substrate and the subsequent hydrogen transfer to the flavin cofactor, resulting in the formation of the N-H bond on flavin. The empirical parameters were calibrated against the experimental data for the simulated reaction in a wild type protein and then used for the calculation of the reaction free energy profile in the I335Y mutant. In very good agreement with the measured kinetic data, mutation increases the free energy barrier for the rate limiting step by slightly more than 1 kcal mol(-1) and consequently decreases the rate constant by about an order of magnitude. The magnitude of the computed effect slightly varies with simulation settings, but always remains in reasonable agreement with the experiment. Analysis of trajectories reveals a major change in the interaction between phenyl rings of the substrate and the neighboring Phe352 residue upon the I335Y mutation due to the increased local polarity, leading to an attenuated quadrupole interaction between the rings and destabilization of the transition state. Additionally, the increased local polarity in the mutant allows for a larger number of water molecules to be present near the active site, effectively shielding the catalytic effect of the enzyme and contributing to the increased barrier.

Angiotensin converting enzyme genotype affects development and course of sarcoidosis in Asian Indians.

PubMed

Tahir, Mohammad; Sharma, S K; Ashraf, Shazia; Mishra, Hemant K

2007-09-01

Studies of serum angiotensin converting enzyme (SACE) activity and its association with ACE gene insertion/deletion (I/D) polymorphism in relation to sarcoidosis have yielded variable results. This has been attributed to possible ethnic differences. Present study was designed to evaluate the relationship between I/D polymorphism and susceptibility to develop sarcoidosis and its effect on SACE activity and disease course in Asian Indian patients with sarcoidosis. ACE genotyping was performed in 72 consecutive patients with sarcoidosis and 199 controls (96 normal healthy individuals and 103 tuberculosis patients taken as disease controls). SACE activity was determined in all patients with sarcoidosis. Various parameters were compared amongst patients with different genotypes as well as between sarcoidosis and control groups. Gene frequency of I and D in control group was 0.6 and 0.4, whereas in patients with sarcoidosis it was 0.35 and 0.65 respectively (p < 0.001). For individuals with D allele (DD&ID genotypes), odds ratios for developing sarcoidosis were 9.0 (95% CI: 3.4; 23.7) and 5.5 (95% CI: 2.2; 13.6) respectively considering individuals with II genotype as reference. Mean SACE activity was highest in patients with DD genotype and followed an order of DD > ID > II. Good response to initial corticosteroids was seen in 6 of 6 (100%) patients with II genotype whereas in only 32 of 37 (84%) with ID and 16 of 25 (64%) with DD (p = 0.013). In Asian Indian population 'D' allele is associated with an increased risk for development of sarcoidosis and patients with 'D' allele show poor response to corticosteroids.

Randomized Trial of Icatibant for Angiotensin-Converting Enzyme Inhibitor-Induced Upper Airway Angioedema.

PubMed

Sinert, Richard; Levy, Phillip; Bernstein, Jonathan A; Body, Richard; Sivilotti, Marco L A; Moellman, Joseph; Schranz, Jennifer; Baptista, Jovanna; Kimura, Alan; Nothaft, Wolfram

Upper airway angioedema is a rare, unpredictable, and at times life-threatening adverse effect of angiotensin-converting enzyme inhibitors (ACE-Is) with no existing effective pharmacologic treatment. Icatibant is a bradykinin B2 receptor antagonist that may be beneficial in patients with ACE-I-induced angioedema. We aimed to evaluate the efficacy of icatibant in subjects with ACE-I-induced angioedema. At 31 centers in 4 countries, adults on ACE-Is who presented within 12 hours of the onset of at least moderately severe angioedema were randomized 1:1 to icatibant 30 mg or placebo administered subcutaneously. The primary efficacy end point was time to meeting discharge criteria after study drug administration, based on the severity of airway symptoms assessed hourly by a blinded physician using clinical ratings across 4 domains. A total of 121 subjects were randomized (icatibant, n = 61; placebo, n = 60); 118 received treatment a median of 7.8 hours from symptom onset. We observed no difference in time to meeting discharge criteria between groups (median, 4.0 hours in each group; P = .63). There also was no difference in time to onset of symptom relief (median, icatibant, 2.0 hours; placebo, 1.6 hours; P = .57) or any other secondary end point. Similar findings were noted in prespecified and post hoc subgroup analyses stratified by symptom severity, time interval to treatment, age, and other clinical covariates. No new safety signals were detected. Icatibant was no more efficacious than placebo in at least moderately severe ACE-I-induced angioedema of the upper airway. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Contribution of Musa paradisiaca in the inhibition of α-amylase, α-glucosidase and Angiotensin-I converting enzyme in streptozotocin induced rats.

PubMed

Shodehinde, Sidiqat A; Ademiluyi, Adedayo O; Oboh, Ganiyu; Akindahunsi, Afolabi A

2015-07-15

Unripe plantain based-diets are part of folklore remedy for the management of diabetes in tropical Africa; however, with the dearth of information on the rationale behind this practice; this study therefore, sought to investigate the antihyperglycemic effect of traditional unripe plantain products (Amala and Booli) in high fat fed/low dose streptozotocin-induced diabetic rats and to provide a possible rationale for their antidiabetic properties. Diabetes was induced experimentally by high fat fed/low dose streptozotocin-diabetic rats (25mg/kg body wt.) and the diabetic rats were fed diets supplemented with 20-40% Amala and Booli for 14 days. The effect of the diets on the blood glucose level, pancreatic α-amylase, intestinal α-glucosidase and Angiotensin-I converting enzyme (ACE) activities and plasma antioxidant status as well as amylose/amylopectin content of the unripe plantain products were determined. A marked increase in the blood glucose, α-amylase, α-glucosidase and ACE activities with a corresponding decrease in plasma antioxidant status was recorded in diabetic rats. However, these indices were significantly (P < 0.05) reversed after unripe plantain product supplemented diet treatments for 14 days. Also, the amylose/amylopectin ratio of the products is 1:3. This study revealed that unripe plantain products exert antihyperglycemic effects which could be attributed to the inhibition of α-amylase and α-glucosidase activities by their constituent phytochemicals as well as their amylose/amylopectin contents in the diabetic rats, hence, providing the possible rationale behind their antidiabetic properties. Copyright © 2015 Elsevier Inc. All rights reserved.

Short communication: Potential of Fresco-style cheese whey as a source of protein fractions with antioxidant and angiotensin-I-converting enzyme inhibitory activities.

PubMed

Tarango-Hernández, S; Alarcón-Rojo, A D; Robles-Sánchez, M; Gutiérrez-Méndez, N; Rodríguez-Figueroa, J C

2015-11-01

Recently, traditional Mexican Fresco-style cheese production has been increasing, and the volume of cheese whey generated represents a problem. In this study, we investigated the chemical composition of Fresco-style cheese wheys and their potential as a source of protein fractions with antioxidant and angiotensin-I-converting enzyme (ACE)-inhibitory activities. Three samples from Fresco, Panela, and Ranchero cheeses whey were physicochemically characterized. Water-soluble extracts were fractionated to obtain whey fractions with different molecular weights: 10-5, 5-3, 3-1 and <1 kDa. The results indicated differences in the lactose, protein, ash, and dry matter contents (% wt/wt) in the different Fresco-style cheese wheys. All whey fractions had antioxidant and ACE-inhibitory activities. The 10-5 kDa whey fraction of Ranchero cheese had the highest Trolox equivalent antioxidant capacity (0.62 ± 0.00 mM), and the 3-1 kDa Panela and Fresco cheese whey fractions showed the highest ACE-inhibitory activity (0.57 ± 0.02 and 0.59 ± 0.04 μg/mL 50%-inhibitory concentration values, respectively). These results suggest that Fresco-style cheese wheys may be a source of protein fractions with bioactivity, and thus could be useful ingredients in the manufacture of functional foods with increased nutritional value. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Angiotensin I-Converting Enzyme (ACE) Inhibitory Activity, Antioxidant Properties, Phenolic Content and Amino Acid Profiles of Fucus spiralis L. Protein Hydrolysate Fractions

PubMed Central

Paiva, Lisete; Neto, Ana Isabel; Baptista, José

2017-01-01

Food protein-derived hydrolysates with multi-bioactivities such as antihypertensive and antioxidant properties have recently received special attention since both activities can play significant roles in preventing cardiovascular diseases. This study reports, for the first time, the angiotensin I-converting enzyme (ACE)-inhibition and antioxidant properties of ultrafiltrate fractions (UF) with different molecular weight ranges (<1, 1–3 and ≥3 kDa) obtained from Fucus spiralis protein hydrolysate (FSPH) digested with cellulase–bromelain. The amino acids profile, recovery yield, protein, peptide and total phenolic contents of these FSPH-UF, and the in vitro digestibility of F. spiralis crude protein were also investigated. FSPH-UF ≥3 kDa presented remarkably higher ACE-inhibition, yield, peptide and polyphenolic (phlorotannins) contents. Antioxidant analysis showed that FSPH-UF <1 kDa and ≥3 kDa exhibited significantly higher scavenging of 2,2-diphenyl-1-picrylhydrazyl radical and ferrous ion-chelating (FIC) activity. FSPH-UF ≥3 kDa had also notably higher ferric reducing antioxidant power (FRAP). Strong correlations were observed between ACE-inhibition and antioxidant activities (FIC and FRAP). The results suggest that ACE-inhibition and antioxidant properties of FSPH-UF may be due to the bioactive peptides and polyphenols released during the enzymatic hydrolysis. In conclusion, this study shows the potential use of defined size FSPH-UF for the prevention/treatment of hypertension and/or oxidative stress-related diseases. PMID:29027934

Antioxidative and angiotensin-I-converting enzyme inhibitory potential of a Pacific Hake ( Merluccius productus ) fish protein hydrolysate subjected to simulated gastrointestinal digestion and Caco-2 cell permeation.

PubMed

Samaranayaka, Anusha G P; Kitts, David D; Li-Chan, Eunice C Y

2010-02-10

Pacific hake fish protein hydrolysate (FPH) with promising chemical assay based antioxidative capacity was studied for in vitro angiotensin-I-converting enzyme (ACE)-inhibitory potential, intestinal cell permeability characteristics, and intracellular antioxidative potential using the Caco-2 cell model system. FPH showed substrate-type inhibition of ACE with IC(50) of 161 microg of peptides/mL. HPLC analysis revealed that different peptides were responsible for antioxidative and ACE-inhibitory activity. FPH inhibited 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidation in Caco-2 cells at noncytotoxic concentrations. In vitro simulated gastrointestinal digestion increased (P < 0.05) antioxidative capacity; ACE-inhibitory activity of FPH remained unchanged, although individual peptide fractions showed decreased or no activity after digestion. Some FPH peptides passed through Caco-2 cells: the permeates showed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity but no ACE-inhibitory activity. These results suggest the potential for application of Pacific hake FPH to reduce oxidative processes in vivo. Further studies are needed to assess prospective antihypertensive effects.

Converting S-limonene synthase to pinene or phellandrene synthases reveals the plasticity of the active site.

PubMed

Xu, Jinkun; Ai, Ying; Wang, Jianhui; Xu, Jingwei; Zhang, Yongkang; Yang, Dong

2017-05-01

S-limonene synthase is a model monoterpene synthase that cyclizes geranyl pyrophosphate (GPP) to form S-limonene. It is a relatively specific enzyme as the majority of its products are composed of limonene. In this study, we converted it to pinene or phellandrene synthases after introducing N345A/L423A/S454A or N345I mutations. Further studies on N345 suggest the polarity of this residue plays a critical role in limonene production by stabilizing the terpinyl cation intermediate. If it is mutated to a non-polar residue, further cyclization or hydride shifts occurs so the carbocation migrates towards the pyrophosphate, leading to the production of pinene or phellandrene. On the other hand, mutant enzymes that still possess a polar residue at this position produce limonene as the major product. N345 is not the only polar residue that may stabilize the terpinyl cation because it is not strictly conserved among limonene synthases across species and there are also several other polar residues in this area. These residues could form a "polar pocket" that may collectively play this stabilizing role. Our study provides important insights into the catalytic mechanism of limonene synthases. Furthermore, it also has wider implications on the evolution of terpene synthases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Central nervous system considerations in the use of beta-blockers, angiotensin-converting enzyme inhibitors, and thiazide diuretics in managing essential hypertension.

PubMed

Gengo, F M; Gabos, C

1988-07-01

The most common mild side effects occurring with use of beta-blockers, thiazide diuretics, and angiotensin-converting enzyme inhibitors for blood pressure control are central nervous system symptoms, specifically lethargy, sedation, and fatigue. These symptoms affect 5% to 10% of patients taking these drugs. The mechanism by which beta-blockers may induce central nervous system effects is uncertain. Relative lipophilicity as a factor affecting penetrance of the blood-brain barrier has not proved to be a reliable predictor of whether the drug will cause such disturbances. Comparisons of atenolol (hydrophilic) and metoprolol (lipophilic) have shown no differences between these drugs with respect to side effects of the central nervous system. The incidence of central nervous system effects with angiotensin-converting enzyme inhibitors is similar to that for most beta-blockers. The precise role of the angiotensin-converting enzyme in the central nervous system is not well defined. Most thiazide diuretics are not associated with major complications of the central nervous system, although electrolyte imbalance may occasionally lead to complaints of neurologic symptoms. Because the incidence of central nervous system effects with these three classes of drugs is so low, concern for the side effects of the central nervous system is not a prime consideration in the choice of an initial antihypertensive agent.

Angiotensin-converting enzyme inhibition studies by natural leech inhibitors by capillary electrophoresis and competition assay.

PubMed

Deloffre, Laurence; Sautiere, Pierre-Eric; Huybrechts, Roger; Hens, Korneel; Vieau, Didier; Salzet, Michel

2004-06-01

A protocol to follow the processing of angiotensin I into angiotensin II by rabbit angiotensin-converting enzyme (ACE) and its inhibition by a novel natural antagonist, the leech osmoregulator factor (LORF) using capillary zonal electrophoresis is described. The experiment was carried out using the Beckman PACE system and steps were taken to determine (a) the migration profiles of angiotensin and its yielded peptides, (b) the minimal amount of angiotensin II detected, (c) the use of different electrolytes and (d) the concentration of inhibitor. We demonstrated that LORF (IPEPYVWD), a neuropeptide previously found in leech brain, is able to inhibit rabbit ACE with an IC(50) of 19.8 micro m. Interestingly, its cleavage product, IPEP exhibits an IC(50) of 11.5 micro m. A competition assay using p-benzoylglycylglycylglycine and insect ACE established that LORF and IPEP fragments are natural inhibitors for invertebrate ACE. Fifty-four percent of insect ACE activity is inhibited with 50 micro m IPEP and 35% inhibition with LORF (25 mm). Extending the peptide at both N- and C-terminus (GWEIPEPYVWDES) and the cleavage of IPEP in IP abolished the inhibitory activity of both peptides. Immunocytochemical data obtained with antisera raised against LORF and leech ACE showed a colocalization between the enzyme and its inhibitor in the same neurons. These results showed that capillary zonal electrophoresis is a useful technique for following enzymatic processes with small amounts of products and constitutes the first evidence of a natural ACE inhibitor in invertebrates.

Bronchoalveolar lavage, serum angiotensin-converting enzyme, and /sup 67/Ga scanning in extrathoracic sarcoidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallaert, B.; Ramon, P.; Fournier, E.

1982-11-01

Results of bronchoalveolar lavage (BAL), 67Ga scanning, and serum angiotensin-converting enzyme (SACE) assay are compared in the assessment of pulmonary involvement in ten cases of extrathoracic sarcoidosis. Standard clinical, radiologic, and pulmonary function tests detected no pulmonary changes in these patients, but BAL demonstrated an increased alveolar lymphocytosis in eight of ten cases. SACE levels were increased in two cases, and the thoracic gallium uptake was normal in all cases. BAL appears to be the best technique for diagnosing latent pulmonary involvement in extrathoracic sarcoidosis.

Omapatrilat, a dual angiotensin-converting enzyme and neutral endopeptidase inhibitor, prevents fatty streak deposit in apolipoprotein E-deficient mice.

PubMed

Arnal, J F; Castano, C; Maupas, E; Mugniot, A; Darblade, B; Gourdy, P; Michel, J B; Bayard, F

2001-04-01

Angiotensin-converting enzyme (ACE) is mainly responsible for converting angiotensin I (AI) to angiotensin II (AII), and ACE inhibitors prevent atherosclerosis in animal models. Neutral endopeptidase 24.11 (NEP) degrades substance P, kinins and atrial natriuretic peptide (ANP), and aortic wall NEP activity was found to be increased in atherosclerosis. In the present study, we have evaluated the effect of candoxatril, a NEP inhibitor, and of omapatrilat, a dual ACE and NEP inhibitor, on the development of fatty streak in apolipoprotein E (apoE)-deficient mice. Groups of ten male apoE-deficient mice were given either placebo, candoxatril 50 mg/kg per day, or omapatrilat 10, or 100 mg/kg per day for 4 months. None of the treatments influenced body weight, serum total or HDL-cholesterol. Compared with the placebo, candoxatril did not protect the mice from fatty streak deposit. In contrast, omapatrilat dose dependently inhibited the constitution of fatty streak in apoE-deficient mice. The precise advantages of the dual ACE and NEP inhibition versus the inhibition of only ACE should now be considered in the prevention of atherosclerosis as well as in the occurrence of its complications.

Angiotensin-converting enzyme insertion/deletion polymorphism is associated with cerebral white matter changes in Alzheimer's disease.

PubMed

Chou, Ping-Song; Wu, Shyh-Jong; Kao, Yi-Hui; Chou, Mei-Chuan; Tai, Shu-Yu; Yang, Yuan-Han

2017-06-01

The presence of cerebral white matter changes (WMC) has been reported as an important predictor of the rapidity of cognitive decline in Alzheimer's disease (AD). The association between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and WMC in AD is yet to be elucidated. The present study aimed to examine the association between the ACE I/D polymorphism and WMC among AD patients in Taiwan. A total of 403 patients clinically diagnosed with AD were recruited in a cross-sectional study carried out in an area hospital in Kaohsiung, Taiwan. The ACE I/D polymorphism was genotyped, and cerebral white matter rating was carried out using the visual rating scale for age-related white matter changes. The I allele was associated with a significantly lower total age-related white matter changes scale score compared with the D allele (4.83 vs 5.93, P = 0.013). The total age-related white matter changes scale score was significantly lower for the I/I genotype than for the I/D (4.37 vs 5.87, P = 0.009) and I/D + D/D genotypes (4.37 vs 5.91, P = 0.006), with no differences observed between the I/I + I/D and the D/D genotypes (5.08 vs 6.09, P = 0.373), after adjustment for age and hypertension. A stratified analysis by sex demonstrated that the I/I genotype was associated with significant lower WMC than other genotypes in women, but not in men. The present study supports the hypothesis that the ACE I/D polymorphism is associated with the severity of WMC in patients with AD. Patients with AD who are homozygous for the I allele might be less likely to develop WMC, especially women. Geriatr Gerontol Int 2017; 17: 945-950. © 2016 Japan Geriatrics Society.

The Colony-Stimulating Factor 3 Receptor T640N Mutation Is Oncogenic, Sensitive to JAK Inhibition, and Mimics T618I.

PubMed

Maxson, Julia E; Luty, Samuel B; MacManiman, Jason D; Paik, Jason C; Gotlib, Jason; Greenberg, Peter; Bahamadi, Swaleh; Savage, Samantha L; Abel, Melissa L; Eide, Christopher A; Loriaux, Marc M; Stevens, Emily A; Tyner, Jeffrey W

2016-02-01

Colony-stimulating factor 3 receptor (CSF3R) mutations have been identified in the majority of chronic neutrophilic leukemia (CNL) and a smaller percentage of atypical chronic myeloid leukemia (aCML) cases. Although CSF3R point mutations (e.g., T618I) are emerging as key players in CNL/aCML, the significance of rarer CSF3R mutations is unknown. In this study, we assess the importance of the CSF3R T640N mutation as a marker of CNL/aCML and potential therapeutic target. Sanger sequencing of leukemia samples was performed to identify CSF3R mutations in CNL and aCML. The oncogenicity of the CSF3R T640N mutation relative to the T618I mutation was assessed by cytokine independent growth assays and by mouse bone marrow transplant. Receptor dimerization and O-glycosylation of the mutants was assessed by Western blot, and JAK inhibitor sensitivity was assessed by colony assay. Here, we identify a CSF3R T640N mutation in two patients with CNL/aCML, one of whom was originally diagnosed with MDS and acquired the T640N mutation upon evolution of disease to aCML. The T640N mutation is oncogenic in cellular transformation assays and an in vivo mouse bone marrow transplantation model. It exhibits many similar phenotypic features to T618I, including ligand independence and altered patterns of O-glycosylation--despite the transmembrane location of T640 preventing access by GalNAc transferase enzymes. Cells transformed by the T640N mutation are sensitive to JAK kinase inhibition to a similar degree as cells transformed by CSF3R T618I. Because of its similarities to CSF3R T618I, the T640N mutation likely has diagnostic and therapeutic relevance in CNL/aCML. ©2015 American Association for Cancer Research.

Two new mutations in the 3' coding region of the glycogen debranching enzyme in a glycogen storage disease type IIIa Ashkenazi Jewish patient.

PubMed

Parvari, R; Shen, J; Hershkovitz, E; Chen, Y T; Moses, S W

1998-04-01

Glycogen storage disease type III (GSD III) is an autosomal recessive disease caused by the deficiency of glycogen debranching enzyme (AGL). We report the finding of two new mutations in a GSD IIIa Ashkenazi Jewish patient. Both mutations are insertion of an adenine into a stretch of 8 adenines towards the 3' end of the coding region, one at position 3904 (3904insA) in exon 30, the second at position 4214 (4214insA) in exon 32. The mutations cause frameshifts and premature terminations of the glycogen debranching enzyme, the first causing a frameshift at amino acid 1304, the second causing a frameshift at amino acid 1408 of the total of 1532. These mutations demonstrate the importance of the 125 amino acids at the carboxy-terminus of the debrancher enzyme for its activity and support the suggestion that the putative glycogen binding domain is located in the carboxy-terminus of the AGL. The mutations cause distinctive single-strand conformation polymorphism (SSCP) patterns enabling easy detection.

Polymorphisms of apolipoprotein E and angiotensin-converting enzyme genes and carotid atherosclerosis in heavy drinkers.

PubMed

Bednarska-Makaruk, Małgorzata; Rodo, Maria; Markuszewski, Cezary; Rozenfeld, Anna; Swiderska, Malgorzata; Habrat, Bogusław; Wehr, Hanna

2005-01-01

To investigate the influence of apolipoprotein E (APOE) and angiotensin-converting enzyme (ACE) gene polymorphisms on carotid artery atherosclerosis in alcoholism. Polymorphism of both genes was identified by DNA analysis in 130 male alcohol-dependent patients. Intima-media thickness (IMT) was measured ultrasonographically. Multivariate regression analysis showed that of all the known risk factors the greatest impact on carotid atherosclerosis in alcoholics was exerted by age, hypertension, LDL cholesterol and fasting plasma glucose levels. Subjects carrying the APO E epsilon4 allele were more liable to develop atherosclerotic changes in carotid arteries compared with subjects with the epsilon3/3 genotype, which showed statistical significance in patients under 50 years of age. No association was shown between ACE I/D polymorphism and carotid atherosclerosis. APO E polymorphism can increase the risk of carotid atherosclerosis development in an alcoholic subject. The association of the APO E epsilon4 allele with carotid atherosclerosis was significant in younger patients. Since the elevated carotid IMT is considered to be a good marker of increased risk of generalized atherosclerosis the consequences could involve both cardiac and cerebrovascular events.

Varied clinical presentations of seven patients with mutations in CYP11A1 encoding the cholesterol side-chain cleavage enzyme, P450scc.

PubMed

Tee, Meng Kian; Abramsohn, Michal; Loewenthal, Neta; Harris, Mark; Siwach, Sudeep; Kaplinsky, Ana; Markus, Barak; Birk, Ohad; Sheffield, Val C; Parvari, Ruti; Pavari, Ruti; Hershkovitz, Eli; Miller, Walter L

2013-02-01

The cholesterol side-chain cleavage enzyme P450scc, encoded by CYP11A1, converts cholesterol to pregnenolone to initiate steroidogenesis. P450scc deficiency can disrupt adrenal and gonadal steroidogenesis, resembling congenital lipoid adrenal hyperplasia clinically and hormonally; only 12 such patients have been reported previously. We sought to expand clinical and genetic experience with P450scc deficiency. We sequenced candidate genes in 7 children with adrenal insufficiency who lacked disordered sexual development. P450scc missense mutations were recreated in the F2 vector, which expresses the fusion protein P450scc-Ferredoxin Reductase-Ferredoxin. COS-1 cells were transfected, production of pregnenolone was assayed, and apparent kinetic parameters were calculated. Previously described P450scc mutants were assayed in parallel. Four of five Bedouin children in one kindred were compound heterozygotes for mutations c.694C>T (Arg232Stop) and c.644T>C (Phe215Ser). Single-nucleotide polymorphism analysis confirmed segregation of these mutations. The fifth kindred member and another Bedouin patient presented in infancy and were homozygous for Arg232Stop. A patient from Fiji presenting in infancy was homozygous for c.358T>C (Arg120Stop). All mutations are novel. As assayed in the F2 fusion protein, P450scc Phe215Ser retained 2.5% of wild-type activity; previously described mutants Leu141Trp and Ala269Val had 2.6% and 12% of wild-type activity, respectively, and Val415Glu and c.835delA lacked detectable activity. Although P450scc is required to produce placental progesterone required to maintain pregnancy, severe mutations in P450scc are compatible with term gestation; milder P450scc mutations may present later without disordered sexual development. Enlarged adrenals usually distinguish steroidogenic acute regulatory protein deficiency from P450scc deficiency, but only DNA sequencing is definitive.

Angiotensin-converting enzyme insertion/deletion polymorphism genotyping error: the cause and a possible solution to the problem.

PubMed

Saracevic, Andrea; Simundic, Ana-Maria; Celap, Ivana; Luzanic, Valentina

2013-07-01

Rigat and colleagues were the first ones to develop a rapid PCR-based assay for identifying the angiotensin converting enzyme insertion/deletion (I/D) polymorphism. Due to a big difference between the length of the wild-type and mute alleles the PCR method is prone to mistyping because of preferential amplification of the D allele causing depicting I/D heterozygotes as D/D homozygotes. The aim of this study was to investigate whether this preferential amplification can be repressed by amplifying a longer DNA fragment in a so called Long PCR protocol. We also aimed to compare the results of genotyping using five different PCR protocols and to estimate the mistyping rate. The study included 200 samples which were genotyped using standard method used in our laboratory, a stepdown PCR, PCR protocol with the inclusion of 4 % DMSO, PCR with the use of insertion specific primers and new Long PCR method. The results of this study have shown that accurate ACE I/D polymorphism genotyping can be accomplished with the standard and the Long PCR method. Also, as of our results, accurate ACE I/D polymorphism genotyping can be accomplished regardless of the method used. Therefore, if the standard method is optimized more cautiously, accurate results can be obtained by this simple, inexpensive and rapid PCR protocol.

Angiotensin-converting enzyme inhibitor (enalapril maleate) accelerates recovery of mouse skin from UVB-induced wrinkles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuura-Hachiya, Yuko; Arai, Koji Y.; Ozeki, Rieko

Highlights: •Angiotensin converting enzyme (ACE) increases in UVB-irradiated skin. •Administration of an ACE inhibitor improved UVB-induced skin wrinkle. •ACE inhibitor improved UVB-induced epidermal hypertrophy. •ACE inhibitor improved transepidermal water loss in the UVB-irradiated skin. -- Abstract: Angiotensin-converting enzyme (ACE) activity and angiotensin II signaling regulate cell proliferation, differentiation, and tissue remodeling, as well as blood pressure, while in skin, angiotensin II signaling is involved in wound healing, inflammation, and pathological scar formation. Therefore, we hypothesized that angiotensin II is also involved in photoaging of skin. In this study, we examined the effect of enalapril maleate, an ACE inhibitor, on recoverymore » of wrinkled skin of hairless mice exposed to long-term UVB irradiation. Immunohistochemical observation revealed that expression of ACE, angiotensin II, and angiotensin II type 1 (AT1) and type 2 (AT2) receptors in the skin was increased after UVB irradiation (3 times/week at increasing intensities for 8 weeks). Administration of enalapril maleate (5 times/week for 6 weeks, starting 1 week after 10-week irradiation) accelerated recovery from UVB-induced wrinkles, epidermal hyperplasia and epidermal barrier dysfunction, as compared with the vehicle control. Our results indicate that ACE and angiotensin II activity are involved in skin photoaging, and suggest that ACE inhibitor such as enalapril maleate may have potential for improvement of photoaged skin.« less

Association of polymorphisms in angiotensin-converting enzyme gene with gestational diabetes mellitus in Indian women

PubMed Central

Aggarwal, Parul; Agarwal, Nutan; Das, Nibhriti; Dalal, Krishna

2016-01-01

Background: Numerous genes have been reported in relation with gestational diabetes mellitus (GDM), but the findings were not consistently replicated across populations, or there have been no detailed studies on them. Previous literatures suggested that, out of all angiotensin converting enzyme (ACE) gene polymorphisms, only ACE insertion/deletion (I/D) gene polymorphism has a strong association with GDM in Asian Indian women. Aim: This study was devoted to evaluate the association of four single nucleotide polymorphisms (SNPs) ACE A240T, C1237T, G2350A and I/D with GDM and Type 2 diabetes mellitus. Materials and Methods: This study recruited 105 GDM cases, 119 Type 2 diabetes mellitus subjects and 120 controls. PCR-RFLP was used for identifying genotypes of ACE A240T, C1237T and G2350A and PCR was performed in the case of ACE I/D. Results: Significant associations of ACE SNP's, C1237T, and G2350A with GDM were observed. Haplotype analysis revealed the remarkably significant evidence of association with SNP combination ACE A240T, C1237T, G2350A, and I/D with GDM patients (P = 0.024). Individuals possessing haplotype “TTAI” (frequency 30% in GDM and 0 in controls) derived from these SNPs had 185 fold increased risk of developing GDM (95% of confidence interval: 11.13–3102.15), which was highest when compared with other 15 haplotypes. Conclusion: Shorter-range haplotypes were also significant, but the only consistently associated alleles were found to be in ACE C1237T, G2350A, and I/D. These results suggested that the variant in close proximity to ACE C1237T, G2350A and/or I/D modulates susceptibility to GDM and noninsulin dependent diabetes mellitus in Indian women. PMID:26958520

Alterations in Circulatory and Renal Angiotensin-Converting Enzyme and Angiotensin-Converting Enzyme 2 in Fetal Programmed Hypertension

PubMed Central

Shaltout, Hossam A.; Figueroa, Jorge P.; Rose, James C.; Diz, Debra I.; Chappell, Mark C.

2009-01-01

Antenatal betamethasone treatment is a widely accepted therapy to accelerate lung development and improve survival in preterm infants. However, there are reports that infants who receive antenatal glucocorticoids exhibit higher systolic blood pressure in their early adolescent years. We have developed an experimental model of programming whereby the offspring of pregnant sheep administered clinically relevant doses of betamethasone exhibit elevated blood pressure. We tested the hypothesis as to whether alterations in angiotensin-converting enzyme (ACE), ACE2, and neprilysin in serum, urine, and proximal tubules are associated with this increase in mean arterial pressure. Male sheep were administered betamethasone (2 doses of 0.17 mg/kg, 24 hours apart) or vehicle at the 80th day of gestation and delivered at term. Sheep were instrumented at adulthood (1.8 years) for direct conscious recording of mean arterial pressure. Serum and urine were collected and proximal tubules isolated from the renal cortex. Betamethasone-treated animals had elevated mean arterial pressure (97±3 versus 83±2 mm Hg; P<0.05) and a 25% increase in serum ACE activity (48.4±7.0 versus 36.0±2.7 fmol/mL per minute) but a 40% reduction in serum ACE2 activity (18.8±1.2 versus 31.4±4.4 fmol/mL per minute). In isolated proximal tubules, ACE2 activity and expression were 50% lower in the treated sheep with no significant change in ACE or neprilysin activities. We conclude that antenatal steroid treatment results in the chronic alteration of ACE and ACE2 in the circulatory and tubular compartments, which may contribute to the higher blood pressure in this model of fetal programming-induced hypertension. PMID:19047579

Angiotensin I-converting enzyme (ACE) inhibitory activity of Fucus spiralis macroalgae and influence of the extracts storage temperature-A short report.

PubMed

Paiva, Lisete; Lima, Elisabete; Neto, Ana Isabel; Baptista, José

2016-11-30

Recently, increasing attention has been paid to the marine algae as a natural source of novel angiotensin-I converting enzyme (ACE) inhibitors, such as the phlorotannins that are the predominant polyphenols in brown algae. This study reports, for the first time, the ACE inhibition of methanol extract/fractions from Azorean brown algae Fucus spiralis (Fs) determined by HPLC-UV method, their total phenolic content (TPC) quantified as phloroglucinol equivalents (PE) and the effect of the Fs dry powder methanol extracts (Fs-DME) storage temperature on ACE inhibition. The results indicate that the ACE inhibition of Fs-DME decreased by 28.8% and 78.2% when stored during 15days at -80°C and -13°C, respectively, as compared with the activity of Fs-DME at a refrigerated temperature of 6°C and assayed immediately after extraction that showed a value of 80.1±2.1%. This Fs-DME sample was fractionated by ultrafiltration membranes into three molecular weight ranges (<1kDa, 1-3kDa and >3kDa), presenting the fraction>3kDa remarkably high ACE inhibition (88.8±2.4%), TPC value (156.6±1.4mg PE/g of dry weight fraction) and yield. Furthermore, chromatographic and spectrophotometric analyses corroborate that phenolic compounds were present in Fs methanol extract/fractions, and also revealed that phloroglucinol occurs in Fs. The results seem to suggest that Azorean Fs can be a source of powerful ACE-inhibitory phlorotannins with potential impact on public health, particularly on hypertensive patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Angiotensin-Converting Enzyme Genotype and Arterial Oxygen Saturation at High Altitude in Peruvian Quechua

PubMed Central

Bigham, Abigail W.; Kiyamu, Melisa; León-Velarde, Fabiola; Parra, Esteban J.; Rivera-Ch, Maria; Shriver, Mark D.

2008-01-01

Abstract Bigham, Abigail W., Melisa Kiyamu, Fabiola León-Verlarde, Esteban J. Parra, Maria Rivera-Ch, Mark D. Shriver, and Tom D. Brutsaert. Angiotensin-converting enzyme genotype and arterial oxygen saturation at high altitude in Peruvian Quechua. High Alt. Med. Biol. 9:167–178, 2008.—The I-allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with performance benefits at high altitude (HA). In n = 142 young males and females of largely Quechua origins in Peru, we evaluated 3 specific hypotheses with regard to the HA benefits of the I-allele: (1) the I-allele is associated with higher arterial oxygen saturation (\\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland,xspace}\\usepackage{amsmath,amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$${\\rm Sa}_{\\rm O_2}$$\\end{document}) at HA, (2) the I-allele effect depends on the acclimatization state of the subjects, and (3) the putative I-allele effect on \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland,xspace}\\usepackage{amsmath,amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$${\\rm Sa}_{\\rm O_2}$$\\end{document} is mediated by the isocapnic hypoxic ventilatory response (HVR, \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland,xspace}\\usepackage{amsmath,amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$$1 / {\\rm min}^{- 1} / \\%{\\rm Sa}_{\\rm O_2}{- 1}$$\\end{document}). The subject participants

Structural basis of peptide recognition by the angiotensin-1 converting enzyme homologue AnCE from Drosophila melanogaster

PubMed Central

Akif, Mohd; Masuyer, Geoffrey; Bingham, Richard J; Sturrock, Edward D; Isaac, R Elwyn; Acharya, K Ravi

2012-01-01

Human somatic angiotensin-1 converting enzyme (ACE) is a zinc-dependent exopeptidase, that catalyses the conversion of the decapeptide angiotensin I to the octapeptide angiotensin II, by removing a C-terminal dipeptide. It is the principal component of the renin-angiotensin–aldosterone system that regulates blood pressure. Hence it is an important therapeutic target for the treatment of hypertension and cardiovascular disorders. Here, we report the structures of an ACE homologue from Drosophila melanogaster (AnCE; a proven structural model for the more complex human ACE) co-crystallized with mammalian peptide substrates (bradykinin, Thr6–bradykinin, angiotensin I and a snake venom peptide inhibitor, bradykinin-potentiating peptide-b). The structures determined at 2-Å resolution illustrate that both angiotensin II (the cleaved product of angiotensin I by AnCE) and bradykinin-potentiating peptide-b bind in an analogous fashion at the active site of AnCE, but also exhibit significant differences. In addition, the binding of Arg–Pro–Pro, the cleavage product of bradykinin and Thr6– bradykinin, provides additional detail of the general peptide binding in AnCE. Thus the new structures of AnCE complexes presented here improves our understanding of the binding of peptides and the mechanism by which peptides inhibit this family of enzymes. Database The atomic coordinates and structure factors for AnCE–Ang II (code 4AA1), AnCE–BPPb (code 4AA2), AnCE–BK (code 4ASQ) and AnCE–Thr6–BK (code 4ASR) complexes have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/) Structured digital abstract AnCE cleaves Ang I by enzymatic study (View interaction) Bradykinin and AnCE bind by x-ray crystallography (View interaction) BPP and AnCE bind by x-ray crystallography (View interaction) AnCE cleaves Bradykinin by enzymatic study (View interaction) Ang II and AnCE bind

Insights into the Hypertensive Effects of Tityus serrulatus Scorpion Venom: Purification of an Angiotensin-Converting Enzyme-Like Peptidase.

PubMed

Cajado-Carvalho, Daniela; Kuniyoshi, Alexandre Kazuo; Duzzi, Bruno; Iwai, Leo Kei; Oliveira, Úrsula Castro de; Junqueira de Azevedo, Inácio de Loiola Meirelles; Kodama, Roberto Tadashi; Portaro, Fernanda Vieira

2016-11-24

The number of cases of envenomation by scorpions has grown significantly in Brazil since 2007, with the most severe cases being caused by the Tityus serrulatus scorpion. Although envenomed patients mostly suffer neurotoxic manifestations, other symptoms, such as hypertension, cannot be exclusively attributed to neurotoxins. Omics analyses have detected plentiful amounts of metalloproteases in T. serrulatus venom. However, the roles played by these enzymes in envenomation are still unclear. Endeavoring to investigate the functions of scorpion venom proteases, we describe here for the first time an Angiotensin I-Converting Enzyme-like peptidase (ACE-like) purified from T. serrulatus venom. The crude venom cleaved natural and fluorescent substrates and these activities were inhibited by captopril. Regarding the serum neutralization, the scorpion antivenom was more effective at blocking the ACE-like activity than arachnid antivenom, although neither completely inhibited the venom cleavage action, even at higher doses. ACE-like was purified from the venom after three chromatographic steps and its identity was confirmed by mass spectrometric and transcriptomic analyses. Bioinformatics analysis showed homology between the ACE-like transcript sequences from Tityus spp. and human testis ACE. These findings advance our understanding of T. serrulatus venom components and may improve treatment of envenomation victims, as ACE-like may contribute to envenomation symptoms, especially the resulting hypertension.

Insights into the Hypertensive Effects of Tityus serrulatus Scorpion Venom: Purification of an Angiotensin-Converting Enzyme-Like Peptidase

PubMed Central

Cajado-Carvalho, Daniela; Kuniyoshi, Alexandre Kazuo; Duzzi, Bruno; Iwai, Leo Kei; de Oliveira, Úrsula Castro; Junqueira de Azevedo, Inácio de Loiola Meirelles; Kodama, Roberto Tadashi; Portaro, Fernanda Vieira

2016-01-01

The number of cases of envenomation by scorpions has grown significantly in Brazil since 2007, with the most severe cases being caused by the Tityus serrulatus scorpion. Although envenomed patients mostly suffer neurotoxic manifestations, other symptoms, such as hypertension, cannot be exclusively attributed to neurotoxins. Omics analyses have detected plentiful amounts of metalloproteases in T. serrulatus venom. However, the roles played by these enzymes in envenomation are still unclear. Endeavoring to investigate the functions of scorpion venom proteases, we describe here for the first time an Angiotensin I-Converting Enzyme-like peptidase (ACE-like) purified from T. serrulatus venom. The crude venom cleaved natural and fluorescent substrates and these activities were inhibited by captopril. Regarding the serum neutralization, the scorpion antivenom was more effective at blocking the ACE-like activity than arachnid antivenom, although neither completely inhibited the venom cleavage action, even at higher doses. ACE-like was purified from the venom after three chromatographic steps and its identity was confirmed by mass spectrometric and transcriptomic analyses. Bioinformatics analysis showed homology between the ACE-like transcript sequences from Tityus spp. and human testis ACE. These findings advance our understanding of T. serrulatus venom components and may improve treatment of envenomation victims, as ACE-like may contribute to envenomation symptoms, especially the resulting hypertension. PMID:27886129

Phe71 in Type III Trypanosomal Protein Arginine Methyltransferase 7 (TbPRMT7) Restricts the Enzyme to Monomethylation.

PubMed

Cáceres, Tamar B; Thakur, Abhishek; Price, Owen M; Ippolito, Nicole; Li, Jun; Qu, Jun; Acevedo, Orlando; Hevel, Joan M

2018-02-27

Protein arginine methyltransferase 7 (PRMT7) is unique within the PRMT family as it is the only isoform known to exclusively make monomethylarginine (MMA). Given its role in epigenetics, the mechanistic basis for the strict monomethylation activity is under investigation. It is thought that PRMT7 enzymes are unable to add a second methyl group because of steric hindrance in the active site that restricts them to monomethylation. To test this, we probed the active site of trypanosomal PRMT7 (TbPRMT7) using accelerated molecular dynamics, site-directed mutagenesis, kinetic, binding, and product analyses. Both the dynamics simulations and experimental results show that the mutation of Phe71 to Ile converts the enzyme from a type III methyltransferase into a mixed type I/II, that is, an enzyme that can now perform dimethylation. In contrast, the serine and alanine mutants of Phe71 preserve the type III behavior of the native enzyme. These results are inconsistent with a sterics-only model to explain product specificity. Instead, molecular dynamics simulations of these variants bound to peptides show hydrogen bonding between would-be substrates and Glu172 of TbPRMT7. Only in the case of the Phe71 to Ile mutation is this interaction between MMA and the enzyme maintained, and the geometry for optimal S N 2 methyl transfer is obtained. The results of these studies highlight the benefit of combined computational and experimental methods in providing a better understanding for how product specificity is dictated by PRMTs.

Mutation in rod PDE6 linked to congenital stationary night blindness impairs the enzyme inhibition by its gamma-subunit.

PubMed

Muradov, Khakim G; Granovsky, Alexey E; Artemyev, Nikolai O

2003-03-25

Photoreceptor cGMP phosphodiesterase (PDE6) is the effector enzyme in the vertebrate visual transduction cascade. The activity of rod PDE6 catalytic alpha- and beta-subunits is blocked in the dark by two inhibitory Pgamma-subunits. The inhibition is released upon light-stimulation of photoreceptor cells. Mutation H258N in PDE6beta has been linked to congenital stationary night blindness (CSNB) in a large Danish family (Rambusch pedigree) (Gal, A., Orth, U., Baehr, W., Schwinger, E., and Rosenberg, T. (1994) Nat. Genet. 7, 64-67.) We have analyzed the consequences of this mutation for PDE6 function using a Pgamma-sensitive PDE6alpha'/PDE5 chimera, Chi16. Biochemical analysis of the H257N mutant, an equivalent of PDE6betaH258N, demonstrates that this substitution does not alter the ability of chimeric PDE to dimerize or the enzyme's catalytic properties. The sensitivity of H257N to a competitive inhibitor zaprinast was also unaffected. However, the mutant displayed a significant impairment in the inhibitory interaction with Pgamma, which was apparent from a approximately 20-fold increase in the K(i) value (46 nM) and incomplete maximal inhibition. The inhibitory defect of H257N is not due to perturbation of noncatalytic cGMP binding to the PDE6alpha' GAF domains. The noncatalytic cGMP-binding characteristics of the H257N mutant were similar to those of the parent PDE6alpha'/PDE5 chimera. Since rod PDE6 in the Rambusch CSNB is a catalytic heterodimer of the wild-type PDE6alpha and mutant PDE6beta, Chi16 and H257N were coexpressed, and a heterodimeric PDE, Chi16/H257N, was isolated. It displayed two Pgamma inhibitory sites with the K(i) values of 5 and 57 nM. Our results support the hypothesis that mutation H258N in PDE6beta causes CSNB through incomplete inhibition of PDE6 activity by Pgamma, which leads to desensitization of rod photoreceptors.

Angiotensin-converting enzyme inhibition and angiotensin AT1 receptor blockade downregulate angiotensin-converting enzyme expression and attenuate renal injury in streptozotocin-induced diabetic rats.

PubMed

Motawi, Tarek K; El-Maraghy, Shohda A; Senousy, Mahmoud A

2013-07-01

Angiotensin-converting enzyme (ACE) is upregulated in the diabetic kidney and contributes to renal injury. This study investigates the possible beneficial effects of the ACE inhibitor (ACEI), enalapril and the AT1 receptor blocker (ARB), valsartan, on renal ACE expression, renal structure, and function in streptozotocin (STZ)-induced diabetic rats. Male Wistar rats were allocated into four groups: control, STZ-diabetic rats, and STZ-diabetic rats treated with either enalapril (10 mg/kg/day) or valsartan (50 mg/kg/day) for 8 weeks. Enalapril and valsartan reduced renal ACE mRNA and protein expression, Na(+) /K(+) -ATPase activity, oxidative stress, and serum transforming growth factor-β1 levels compared to the diabetic group. Both treatments normalized renal nitrate/nitrite levels and ameliorated the observed histopathological changes. In conclusion, ACE downregulation by ACEI and ARB indicates that angiotensin II upregulates ACE through AT1 receptor. Prevention of diabetes-induced changes in ACE expression and Na(+) /K(+) -ATPase activity could be a new explanation of the renoprotective effects of ACEIs and ARBs. © 2013 Wiley Periodicals, Inc.

NT5E Mutations and Arterial Calcifications

PubMed Central

St. Hilaire, Cynthia; Ziegler, Shira G.; Markello, Thomas C.; Brusco, Alfredo; Groden, Catherine; Gill, Fred; Carlson-Donohoe, Hannah; Lederman, Robert J.; Chen, Marcus Y.; Yang, Dan; Siegenthaler, Michael P.; Arduino, Carlo; Mancini, Cecilia; Freudenthal, Bernard; Stanescu, Horia C.; Zdebik, Anselm A.; Chaganti, R. Krishna; Nussbaum, Robert L.; Kleta, Robert; Gahl, William A.; Boehm, Manfred

2011-01-01

BACKGROUND Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. METHODS We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. RESULTS We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients’ cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. CONCLUSIONS We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research

Endothelin-converting enzyme 2 differentially regulates opioid receptor activity

PubMed Central

Gupta, A; Fujita, W; Gomes, I; Bobeck, E; Devi, L A

2015-01-01

BACKGROUND AND PURPOSE Opioid receptor function is modulated by post-activation events such as receptor endocytosis, recycling and/or degradation. While it is generally understood that the peptide ligand gets co-endocytosed with the receptor, relatively few studies have investigated the role of the endocytosed peptide and peptide processing enzymes in regulating receptor function. In this study, we focused on endothelin-converting enzyme 2 (ECE2), a member of the neprilysin family of metallopeptidases that exhibits an acidic pH optimum, localizes to an intracellular compartment and selectively processes neuropeptides including opioid peptides in vitro, and examined its role in modulating μ receptor recycling and resensitization. EXPERIMENTAL APPROACH The effect of ECE2 inhibition on hydrolysis of the endocytosed peptide was examined using thin-layer chromatography and on μ opioid receptor trafficking using either elisa or microscopy. The effect of ECE2 inhibition on receptor signalling was measured using a cAMP assay and, in vivo, on antinociception induced by intrathecally administered opioids by the tail-flick assay. KEY RESULTS The highly selective ECE2 inhibitor, S136492, significantly impaired μ receptor recycling and signalling by only those ligands that are ECE2 substrates and this was seen both in heterologous cells and in cells endogenously co-expressing μ receptors with ECE2. We also found that ECE2 inhibition attenuated antinociception mediated only by opioid peptides that are ECE2 substrates. CONCLUSIONS AND IMPLICATIONS These results suggest that ECE2, by selectively processing endogenous opioid peptides in the endocytic compartment, plays a role in modulating opioid receptor activity. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2 PMID:24990314

Insertion/Deletion Polymorphisms and Serum Angiotensin-converting Enzyme Levels in Iranian Patients with Sarcoidosis

PubMed Central

JAVADI, Alireza; SHAMAEI, Masoud; ZAREI, Masoud; REZAEIAN, Lida; KIANI, Arda; ABEDINI, Atefeh

2016-01-01

Background: Sarcoidosis is a multisystem inflammatory disease of unknown origin with characterization of small granulomas. Angiotensin-converting enzyme (ACE) is a pathophysiologic marker of sarcoidosis. We present the ACE insertion/deletion (I/D) polymorphism in correlation with serum ACE level in Iranian patients with sarcoidosis. Methods: From Jan 2014 to Jan 2015, 102 Iranian patients who histopathologically diagnosed for sarcoidosis and 192 healthy age and sex-matched controls were recruited. PCR was used for detection of I/D polymorphism in ACE gene. Results: Frequency of II/ID/DD genotype in sarcoidosis disease was 17%, 35.5%, and 47.1%, respectively. The frequency of D allele was 0.65. A significant association between I/D genotypes and mean of sACE level was seen (DD=85.2±22.9, P<0.001). More frequent genotype in sarcoidosis patients was DD (47%), ID genotype (45.9%) was found more in controls. Logistic regression analysis adjusting age and sex showed that ID to II (OR=0.35, 95%CI=0.17–0.73, P=0.005) and DD to II (OR=2.11, 95%CI=0.98–4.54, P=0.05) could be considered as a predictor factor for the disease activity. No significant model for men in sarcoidosis group was seen, while women with II/ID were associated with a reduced risk for the disease. Conclusion: Although more regional studies with appropriate statistical scale must be done to provide a better diagnosis and prognostic tool for this disease, this study demonstrates that ID and DD genotype could be predictive factors for sarcoidosis. PMID:28032065

31 CFR 363.163 - How do I convert an eligible definitive savings bond?

Code of Federal Regulations, 2010 CFR

2010-07-01

... REGULATIONS GOVERNING SECURITIES HELD IN TREASURYDIRECT Conversion of a Definitive Savings Bond § 363.163 How do I convert an eligible definitive savings bond? We will provide online instructions for converting...

Genetic advantageous predisposition of angiotensin converting enzyme id polymorphism in Tunisian athletes.

PubMed

Znazen, Hela; Mejri, Aouatef; Touhami, Imed; Chtara, Moktar; Siala, Hajer; LE Gallais, Daniel; Ahmetov, Ildus I; Messaoud, Taeib; Chamari, Karim; Soussi, Nizar

2016-06-01

ID polymorphism of the gene coding for the angiotensin I-converting enzyme (ACE) represents a determining factor in physical and athletic performance in the context of genetic conditioning of sports predisposition. The aim of this study was to show the potential importance of genetic factors in relation to the athletic status in Tunisian athletes. The ACE genotypes were established using polymerase chain reaction (PCR) amplification for 282 Tunisian athletes (endurance: N.=149 - power: N.=133), and 211 sedentary volunteers. No significant difference was found in the ACE genotype distribution between athletes (36% DD, 49% ID, 15% II) and controls (CTR) (39% DD, 46% ID, 15% II; P=0.72). In contrast, a high significant difference between endurance and power groups were noted in genotype and alleles (χ2=10.32, P=0.0057; χ2=4,752, P=0.029, respectively). The elite endurance-athletes (N.=72) possess some inherent genetic advantage predisposing them to superior athletic performances compared to CTR for ACE alleles (χ2=3.51, P=0.06). In addition endurance trained athletes were also significantly different from CTR for ACE genotype (χ2=6.05, P=0.04). Furthermore, a significant difference have been found between elite power-athletes (N.=59) and CTR for ACE alleles (χ2=3.79, P=0.05). Tunisian athletes exhibit insertion (I) and deletion (D) alleles of the ACE polymorphism associated with a high level of human endurance and power performance, respectively. This genetic background plays an important role in sporting potential and causes some individuals to be better adapted to specific physical training. This should be considered in athlete development to identify which sporting specialties should be trained for Tunisian talent promotion.

Murine recombinant angiotensin-converting enzyme 2 attenuates kidney injury in experimental Alport syndrome.

PubMed

Bae, Eun Hui; Fang, Fei; Williams, Vanessa R; Konvalinka, Ana; Zhou, Xiaohua; Patel, Vaibhav B; Song, Xuewen; John, Rohan; Oudit, Gavin Y; Pei, York; Scholey, James W

2017-06-01

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase in the renin-angiotensin system that catalyzes the breakdown of angiotensin II to angiotensin 1-7. We have reported that ACE2 expression in the kidney is reduced in experimental Alport syndrome but the impact of this finding on disease progression has not been studied. Accordingly, we evaluated effects of murine recombinant ACE2 treatment in Col4a3 knockout mice, a model of Alport syndrome characterized by proteinuria and progressive renal injury. Murine recombinant ACE2 (0.5 mg/kg/day) was administered from four to seven weeks of age via osmotic mini-pump. Pathological changes were attenuated by murine recombinant ACE2 treatment which ameliorated kidney fibrosis as shown by decreased expression of COL1α1 mRNA, less accumulation of extracellular matrix proteins, and inhibition of transforming growth factor-β signaling. Further, increases in proinflammatory cytokine expression, macrophage infiltration, inflammatory signaling pathway activation, and heme oxygenase-1 levels in Col4a3 knockout mice were also reduced by murine recombinant ACE2 treatment. Lastly, murine recombinant ACE2 influenced the turnover of renal ACE2, as it suppressed the expression of tumor necrosis factor-α converting enzyme, a negative regulator of ACE2. Thus, treatment with exogenous ACE2 alters angiotensin peptide metabolism in the kidneys of Col4a3 knockout mice and attenuates the progression of Alport syndrome nephropathy. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Computationally optimized deimmunization libraries yield highly mutated enzymes with low immunogenicity and enhanced activity.

PubMed

Salvat, Regina S; Verma, Deeptak; Parker, Andrew S; Kirsch, Jack R; Brooks, Seth A; Bailey-Kellogg, Chris; Griswold, Karl E

2017-06-27

Therapeutic proteins of wide-ranging function hold great promise for treating disease, but immune surveillance of these macromolecules can drive an antidrug immune response that compromises efficacy and even undermines safety. To eliminate widespread T-cell epitopes in any biotherapeutic and thereby mitigate this key source of detrimental immune recognition, we developed a Pareto optimal deimmunization library design algorithm that optimizes protein libraries to account for the simultaneous effects of combinations of mutations on both molecular function and epitope content. Active variants identified by high-throughput screening are thus inherently likely to be deimmunized. Functional screening of an optimized 10-site library (1,536 variants) of P99 β-lactamase (P99βL), a component of ADEPT cancer therapies, revealed that the population possessed high overall fitness, and comprehensive analysis of peptide-MHC II immunoreactivity showed the population possessed lower average immunogenic potential than the wild-type enzyme. Although similar functional screening of an optimized 30-site library (2.15 × 10 9 variants) revealed reduced population-wide fitness, numerous individual variants were found to have activity and stability better than the wild type despite bearing 13 or more deimmunizing mutations per enzyme. The immunogenic potential of one highly active and stable 14-mutation variant was assessed further using ex vivo cellular immunoassays, and the variant was found to silence T-cell activation in seven of the eight blood donors who responded strongly to wild-type P99βL. In summary, our multiobjective library-design process readily identified large and mutually compatible sets of epitope-deleting mutations and produced highly active but aggressively deimmunized constructs in only one round of library screening.

Role of angiotensin converting enzyme in the vascular effects of an endopeptidase 24.15 inhibitor.

PubMed Central

Telford, S E; Smith, A I; Lew, R A; Perich, R B; Madden, A C; Evans, R G

1995-01-01

1. We investigated the role of angiotensin converting enzyme (ACE) in the cardiovascular effects of N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (cFP), a peptidase inhibitor selective for metalloendopeptidase (EP) E.C. 3.4.24.15. 2. In conscious rabbits, cFP (5 mg kg-1, i.v.) markedly slowed the degradation of [3H]-bradykinin, potentiated the depressor response to right atrial administration of bradykinin (10-1000 ng kg-1), and inhibited the pressor response to right atrial angiotensin I (10-100 ng kg-1). In each of these respects, the effects of cFP were indistinguishable from those of the ACE inhibitor, captopril (0.5 mg plus 10 mg kg-1h-1 i.v.). Furthermore, the effects of combined administration of cFP and captopril were indistinguishable from those of captopril alone. 3. In experimentally naive anaesthetized rats, cFP administration (9.3 mg kg-1, i.v.) was followed by a moderate but sustained fall in arterial pressure of 13 mmHg. However, in rats pretreated with bradykinin (50 micrograms kg-1) a more pronounced fall of 30 mmHg was observed. Captopril (5 mg kg-1) had similar hypotensive effects to those of cFP, and cFP had no effect when it was administered after captopril. 4. CFP displaced the binding of [125I]-351A (the p-hydroxybenzamidine derivative of lisinopril) from preparations of rat plasma ACE and solubilized lung membrane ACE (KD = 1.2 and 0.14 microM respectively), and inhibited rat plasma ACE activity (KI = 2.4 microM). Addition of phosphoramidon (10 microM), an inhibitor of a range of metalloendopeptidases, including neutral endopeptidase (E.C.3.4.24.11), markedly reduced the potency of cFP in these systems.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7620708

Degradation of neurotensin by rat brain synaptic membranes: involvement of a thermolysin-like metalloendopeptidase (enkephalinase), angiotensin-converting enzyme, and other unidentified peptidases.

PubMed

Checler, F; Vincent, J P; Kitabgi, P

1983-08-01

Neurotensin was inactivated by membrane-bound and soluble degrading activities present in purified preparations of rat brain synaptic membranes. Degradation products were identified by HPLC and amino acid analysis. The major points of cleavage of neurotensin were the Arg8-Arg9, Pro10-Tyr11, and Tyr11-Ile12 peptide bonds with the membrane-bound activity and the Arg8-Arg9 and Pro10-Tyr11 bonds with the soluble activity. Several lines of evidence indicated that the cleavage of the Arg8-Arg9 bond by the membrane-bound activity resulted mainly from the conversion of neurotensin1-10 to neurotensin1-8 by a dipeptidyl carboxypeptidase. In particular, captopril inhibited this cleavage with an IC50 (5.7 nM) close to its K1 (7 nM) for angiotensin-converting enzyme. Thiorphan inhibited the cleavage at the Tyr11-Ile12 bond by the membrane-bound activity with an IC50 (17 nM) similar to its K1 (4.7 nM) for enkephalinase. Both cleavages were inhibited by 1,10-phenanthroline. These and other data suggested that angiotensin-converting enzyme and a thermolysin-like metalloendopeptidase (enkephalinase) were the membrane-bound peptidases responsible for cleavages at the Arg8-Arg9 and Tyr11-Ile12 bonds, respectively. In contrast, captopril had no effect on the cleavage at the Arg8-Arg9 bond by the soluble activity, indicating that the enzyme responsible for this cleavage was different from angiotensin-converting enzyme. The cleavage at the Pro10-Tyr11 bond by both the membrane-bound and the soluble activities appeared to be catalyzed by an endopeptidase different from known brain proline endopeptidases. The possibility is discussed that the enzymes described here participate in physiological mechanisms of neurotensin inactivation at the synaptic level.

Renal oxygen content is increased in healthy subjects after angiotensin-converting enzyme inhibition.

PubMed

Stein, Anna; Goldmeier, Silvia; Voltolini, Sarah; Setogutti, Enio; Feldman, Carlos; Figueiredo, Eduardo; Eick, Renato; Irigoyen, Maria; Rigatto, Katya

2012-07-01

The association between renal hypoxia and the development of renal injury is well established. However, no adequate method currently exists to non-invasively measure functional changes in renal oxygenation in normal and injured patients. R2* quantification was performed using renal blood oxygen level-dependent properties. Five healthy normotensive women (50 ± 5.3 years) underwent magnetic resonance imaging in a 1.5T Signa Excite HDx scanner (GE Healthcare, Waukesha, WI). A multiple fast gradient-echo sequence was used to acquire R2*/T2* images (sixteen echoes from 2.1 ms/slice to 49.6 ms/slice in a single breath hold per location). The images were post-processed to generate R2* maps for quantification. Data were recorded before and at 30 minutes after the oral administration of an angiotensin II-converting enzyme inhibitor (captopril, 25 mg). The results were compared using an ANOVA for repeated measurements (mean + standard deviation) followed by the Tukey test. ClinicalTrials.gov: NCT01545479. A significant difference (p<0.001) in renal oxygenation (R2*) was observed in the cortex and medulla before and after captopril administration: right kidney, cortex = 11.08 ± 0.56 ms, medulla = 17.21 ± 1.47 ms and cortex = 10.30 ± 0.44 ms, medulla = 16.06 ± 1.74 ms, respectively; and left kidney, cortex= 11.79 ± 1.85 ms, medulla = 17.03 ± 0.88 ms and cortex = 10.89 ± 0.91 ms, medulla = 16.43 ± 1.49 ms, respectively. This result suggests that the technique efficiently measured alterations in renal blood oxygenation after angiotensin II-converting enzyme inhibition and that it may provide a new strategy for identifying the early stages of renal disease and perhaps new therapeutic targets.

Potentiation of Paclitaxel-Induced Pain Syndrome in Mice by Angiotensin I Converting Enzyme Inhibition and Involvement of Kinins.

PubMed

Brusco, Indiara; Silva, Cássia Regina; Trevisan, Gabriela; de Campos Velho Gewehr, Camila; Rigo, Flávia Karine; La Rocca Tamiozzo, Lidia; Rossato, Mateus Fortes; Tonello, Raquel; Dalmolin, Gerusa Duarte; de Almeida Cabrini, Daniela; Gomez, Marcus Vinícius; Ferreira, Juliano; Oliveira, Sara Marchesan

2017-12-01

Paclitaxel is a chemotherapeutic agent used to treat solid tumours. However, it causes an acute and neuropathic pain syndrome that limits its use. Among the mechanisms involved in neuropathic pain caused by paclitaxel is activation of kinin receptors. Angiotensin converting enzyme (ACE) inhibitors can enhance kinin receptor signalling. The goal of this study was to evaluate the role of kinins on paclitaxel-associated acute pain syndromes (P-APS) and the effect of ACE inhibition on P-APS and paclitaxel-associated chronic peripheral neuropathy (P-CPN) in mice. Herein, we show that paclitaxel caused mechanical allodynia and spontaneous nociceptive behaviour that was reduced by antagonists of kinin receptors B 1 (DALBk and SSR240612) and B 2 (Hoe140 and FR173657). Moreover, enalapril (an ACE inhibitor) enhanced the mechanical allodynia induced by a low dose of paclitaxel. Likewise, paclitaxel injection inhibited ACE activity and increased the expressions of B 1 and B 2 receptors and bradykinin-related peptides levels in peripheral tissue. Together, our data support the involvement of kinin receptors in the P-APS and suggest kinin receptor antagonists to treat this syndrome. Because hypertension is the most frequent comorbidity affecting cancer patients, treatment of hypertension with ACE inhibitors in patients undergoing paclitaxel chemotherapy should be reviewed, since this could enhance the P-APS and P-CPN.

Screening of Zulu medicinal plants for angiotensin converting enzyme (ACE) inhibitors.

PubMed

Duncan, A C; Jäger, A K; van Staden, J

1999-12-15

Twenty plants used by traditional healers in South Africa for the treatment of high blood pressure were investigated for their anti-hypertensive properties, utilizing the angiotensin converting enzyme assay. A hit rate of 65% was achieved, with the highest inhibition (97%) obtained by Adenopodia spicata leaves. A further seven plants exhibited an inhibition greater than 70% and five more over 50%. The leaves of the plants showed the greatest levels of inhibition. There was little difference in the overall hit rate between ethanolic and aqueous extracts, although in most cases there was a marked difference in activity between aqueous and ethanolic extracts from the same species. Plants exhibiting inhibition levels greater than 50% were further tested for the presence of tannins in order to eliminate possible false positives. Active plants that did not contain tannins were Agapanthus africanus, Agave americana, Clausena anisata, Dietes iridioides, Mesembruanthemum spp., Stangeria eriopus and Tulbaghia violacea.

Glycogen branching enzyme (GBE1) mutation causing equine glycogen storage disease IV.

PubMed

Ward, Tara L; Valberg, Stephanie J; Adelson, David L; Abbey, Colette A; Binns, Matthew M; Mickelson, James R

2004-07-01

Comparative biochemical and histopathological evidence suggests that a deficiency in the glycogen branching enzyme, encoded by the GBE1 gene, is responsible for a recently identified recessive fatal fetal and neonatal glycogen storage disease (GSD) in American Quarter Horses termed GSD IV. We have now derived the complete GBE1 cDNA sequences for control horses and affected foals, and identified a C to A substitution at base 102 that results in a tyrosine (Y) to stop (X) mutation in codon 34 of exon 1. All 11 affected foals were homozygous for the X34 allele, their 11 available dams and sires were heterozygous, and all 16 control horses were homozygous for the Y34 allele. The previous findings of poorly branched glycogen, abnormal polysaccharide accumulation, lack of measurable GBE1 enzyme activity and immunodetectable GBE1 protein, coupled with the present observation of abundant GBE1 mRNA in affected foals, are all consistent with the nonsense mutation in the 699 amino acid GBE1 protein. The affected foal pedigrees have a common ancestor and contain prolific stallions that are likely carriers of the recessive X34 allele. Defining the molecular basis of equine GSD IV will allow for accurate DNA testing and the ability to prevent occurrence of this devastating disease affecting American Quarter Horses and related breeds.

Gender difference of serum angiotensin-converting enzyme (ACE) activity in DD genotype of ACE insertion/deletion polymorphism in elderly Chinese.

PubMed

Zhang, Ya-Feng; Cheng, Qiong; Tang, Nelson L S; Chu, Tanya T W; Tomlinson, Brian; Liu, Fan; Kwok, Timothy C Y

2014-12-01

In this study we investigated the gender difference of serum angiotensin-converting enzyme (ACE) activity in a population of Hong Kong-dwelling elderly Chinese. A total of 1767 (843 male, 924 female) Hong Kong-dwelling elderly Chinese were recruited. ACE I/D genotypes were identified by polymerase chain reaction amplification and serum ACE activity was determined using a commercially available kinetic kit. ACE I/D genotype distribution was compared by chi-square test, the correlation between ACE I/D polymorphism and serum ACE activity was analysed by ANOVA test and gender difference of serum ACE activity of different genotypes was compared by independent sample t-test. No statistically significant difference of genotype distribution between male and female subjects was found. Serum ACE activity was significantly correlated with ACE genotype. Overall, there was no gender difference of serum ACE activity; however, when sub-grouping the subjects by ACE I/D genotype, male subjects with DD genotype had higher serum ACE activity than female subjects with DD genotype. No significant gender difference of genotype distribution was found in elderly Chinese. Serum ACE activity was significantly correlated with ACE I/D polymorphism in elderly Chinese. Male subjects with DD genotype had higher serum ACE activity than female subjects with DD genotype. © The Author(s) 2013.

Inhibition of angiotensin-converting enzyme increases oestradiol production in ewes submitted to oestrous synchronization protocol.

PubMed

Costa, A s; Junior, A S; Viana, G E N; Muratori, M C S; Reis, A M; Costa, A P R

2014-10-01

This study aimed at evaluating the effects of angiotensin-converting enzyme inhibitor (enalapril) and angiotensin II antagonist (valsartan) on the oestradiol and progesterone production in ewes submitted to oestrous synchronization protocol. The animals were weighed and randomly divided into three groups (n = 7). A pre-experiment conducted to verify the effectiveness and toxicity of enalapril (0.5 mg/kg LW) and valsartan (2.2 mg/kg LW) showed that, in the doses used, these drugs were effective in reducing blood pressure without producing toxic effects. In the experiment, all animals were subjected to oestrous synchronization protocol during 12 days. On D10, D11 and D12, animals received saline, enalapril or valsartan (same doses of the pre-experiment), according to the group randomly divided. The hormonal analysis showed an increase in oestradiol on the last day of the protocol (D12) in animals that received enalapril (p < 0.05), but not in other groups, without changing the concentration of progesterone in any of the treatments. It is concluded that valsartan and enalapril are safe and effective subcutaneously for use in sheep and that the angiotensin-converting enzyme (ACE) inhibition with enalapril leads to an increase in oestradiol production near ovulation without changing the concentration of progesterone. This shows that ACE inhibition may be a useful tool in reproductive biotechnologies involving induction and synchronization of oestrus and ovulation in sheep. © 2014 Blackwell Verlag GmbH.

Converting Enzymes into Tools of Industrial Importance.

PubMed

Prasad, Shivcharan; Roy, Ipsita

2018-01-01

Enzymes have applications in numerous biotechnological products and processes that are commonly used in the production of food and beverages, cleaning supplies, clothing, paper products, transportation fuels, pharmaceuticals, and monitoring devices. Enzymes, however, are optimized to function under physiological conditions. Any change in reaction conditions results in their activity as well as stability being compromised. Hence, most of the natural biomolecules are not suitable for industrial applications. Modifications are required to develop efficient and successful reagents as per demand. Protein engineering can be applied to cope up with these situations. This review describes some of the novel uses/unusual properties of enzymes as biological catalysts. It explains the different ways in which enzymes can be and have been used under non-native conditions. Different strategies have been discussed regarding stabilization of enzyme as well optimum conditions of its uses in different industries. The following patents databases were consulted: European Patent Office (EPO), the United States Patent and Trademark Office (USPTO), Patent scope Search International and National Patent Collections (WIPO) and Google Patents. The review illustrates the width of the umbrella of applications covered by biocatalysts. Employing the tools of solvent and protein engineering, viz. non-aqueous media, additives, immobilization, mutagenesis, to name a few; biotechnology has been able to make enzyme catalyzed processes an essential components of the industrialist's armoury. The article lists a number of successful examples, both of patented technology as well as biocatalysts which are currently being used in the industry, to highlight the accomplishments of technologies which have been adopted till now for making enzyme technology industrially viable. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of angiotensin converting enzyme inhibitor on chronic ischemic patients.

PubMed

Kawakami, N; Yamashita, T; Nakano, S; Ishihara, H; Kitahara, T; Nakashima, K; Kashiwagi, S; Ito, H

1996-01-01

Most of patients with cerebrovascular disease are associated with hypertension. Hypertension induces progressive atheromatous changes in cerebral arteries, and often causes steno-occlusive lesions of cerebral arteries. Angiotensin converting enzyme (ACE) inhibitor cilazapril is one of the antihypertensive drugs. It was reported that cilazapril improved resting cerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) in experimental studies. In this clinical study, the authors investigated whether long-term treatment with cilazapril could improve CBF and CRC in patients with steno-occlusive lesions of the major cerebral arterial trunk, measured by stable xenon computerized tomography (Xe-CT) with acetazolamide challenge. On the other hand, CBF and CRC in the calcium blocker-treated patients were measured in the same way. CBF did not change after long-term treatment with both cilazapril and calcium blocker. In the cilazapril-treated group, CRC was increased significantly (p < 0.05). However, CRC did not change in the calcium blocker-treated group. It was recognized that long-term treatment with cilazapril did not decrease CBF and improved CRC in patients with occlusive lesions of the major cerebral arterial trunk.

Increased frequency of angiotensin-converting enzyme DD genotype in Saudi overweight and obese patients.

PubMed

El-Hazmi, Mohsen Af; Warsy, Arjumand S

2003-01-01

Several studies have been carried out to investigate the insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) in obese and normal weight individuals, often with contradictory results in different populatios. In some studies, the DD genotype occurs at a high frequency in obesity, while in others no association has been demonstrated. Since obesity and overweight are of frequent occurrence in the Saudi population, we initiated this study to investigate the I/D polymorphism of ACE in obese, overweight and normal weight Saudis. The study group included 457 Saudi males and females. The height and weight were measured and body mass index (BMI) was calculated. Based on the BMI value, the total study population was classified as normal, overweight and obese. A total of 117 obese (BMI >30 (kg/m(2))), 185 overweight (BMI=25-29.9 (kg/m(2))) and 155 normal weight individuals (BMI< (kg/m (2)) were enrolled. Polymerase chain reaction (PCR) and agarose gel electrophoresis were used to study the ACE polymorphism. For the deletion (D) form, a 190 bp and for the insertion (I) form, 490 bp DNA fragment were obtained on 2% agarose gel electrophoresis. The frequency of DD genotype was 76.9% in the obese, and 73.5% in the overweight individuals, compared to 19.66% and 24.86% of the ID genotype in the obese and overweight, respectively. Among the normal weight individuals, the frequency was significantly lower for DD and higher for the ID genotype, i.e., 58.7% for DD and 40% for ID. The allele frequencies in the obese were 0.867 and 0.133 for the D and I alleles, respectively. While in the overweight, the frequencies were 0.859 and 0.141 for these alleles, respectively, compared to 0.787 and 0.213 in the normal weight individuals. The DD genotype and D allele occur at a high frequency in Saudi overweight and obese individuals, and may have some role in fat accumulation by affecting metabolic pathways of fat, thus leading to the development of overweight and obesity.

Effects of missense mutations in sortase A gene on enzyme activity in Streptococcus mutans.

PubMed

Zhuang, P L; Yu, L X; Tao, Y; Zhou, Y; Zhi, Q H; Lin, H C

2016-04-11

Streptococcus mutans (S. mutans) is the major aetiological agent of dental caries, and the transpeptidase Sortase A (SrtA) plays a major role in cariogenicity. The T168G and G470A missense mutations in the srtA gene may be linked to caries susceptibility, as demonstrated in our previous studies. This study aimed to investigate the effects of these missense mutations of the srtA gene on SrtA enzyme activity in S. mutans. The point mutated recombinant S.mutans T168G and G470A sortases were expressed in expression plasmid pET32a. S. mutans UA159 sortase coding gene srtA was used as the template for point mutation. Enzymatic activity was assessed by quantifying increases in the fluorescence intensity generated when a substrate Dabcyl-QALPNTGEE-Edans was cleaved by SrtA. The kinetic constants were calculated based on the curve fit for the Michaelis-Menten equation. SrtA△N40(UA159) and the mutant enzymes, SrtA△N40(D56E) and SrtA△N40(R157H), were expressed and purified. A kinetic analysis showed that the affinity of SrtA△N40(D56E) and SrtA△N40(R157H) remained approximately equal to the affinity of SrtA△N40(UA159), as determined by the Michaelis constant (K m ). However, the catalytic rate constant (k cat ) and catalytic efficiency (k cat /K m ) of SrtA△N40(D56E) were reduced compared with those of SrtA△N40(R157H) and SrtA△N40(UA159), whereas the k cat and k cat /K m values of SrtA△N40(R157H) were slightly lower than those of SrtA△N40(UA159). The findings of this study indicate that the T168G missense mutation of the srtA gene results in a significant reduction in enzymatic activity compared with S. mutans UA159, suggesting that the T168G missense mutation of the srtA gene may be related to low cariogenicity.

[Angiotensin converting enzyme 2 and its emerging role in the regulation of the renin angiotensin system].

PubMed

Soler, María José; Lloveras, Josep; Batlle, Daniel

2008-07-12

The renin-angiotensin system (RAS) plays a key role in the regulation of cardiovascular and renal function. Thus, RAS blockade with an angiotensin-converting enzyme (ACE) and/or angiotensin receptor blocker decreases blood pressure, cardiovascular events, and delays the progression of kidney disease. The discovery of ACE2, a homologue of ACE, capable of degrading angiotensin II to angiotensin 1-7, may offer new insights into the RAS. In this review we discuss the possible protective role of ACE2 in different organs, namely heart, lungs and kidneys. The role of this enzyme is inferred from recent studies performed using genetically manipulated mice that lack the ACE2 gene and also mice treated with pharmacological ACE2 inhibitors. These results suggest that ACE2 might be a new therapeutic target within the RAS.

Substance P-induced bronchoconstriction in the guinea pig. Enhancement by inhibitors of neutral metalloendopeptidase and angiotensin-converting enzyme.

PubMed

Shore, S A; Stimler-Gerard, N P; Coats, S R; Drazen, J M

1988-02-01

We tested the effects of the neutral metalloendopeptidase (NEP) inhibitor, thiorphan (0.17, 0.5, and 1.7 mg i.v), and the angiotensin-converting enzyme (ACE) inhibitor, captopril (0.5, 1.7, and 5.0 mg i.v.), on the bronchoconstrictor response to rapid intravenous infusions of substance P (0.1 to 30 nmol/kg) in anesthetized, mechanically ventilated guinea pigs. The decreases in pulmonary conductance and dynamic compliance caused by substance P were greater in animals treated with either thiorphan or captopril than in control animals. Thiorphan (0.5 mg) had no effect on airway responsiveness to intravenously administered methacholine, whereas captopril (1.7 mg) caused a small increase in methacholine responsiveness. Both drugs significantly increased the recovery of immunoreactive substance P in arterial plasma after exogenous administration of the peptide. We conclude that degradation of substance P by both NEP and ACE is important for determining the magnitude of the bronchoconstriction caused by intravenous administration of this neuropeptide. These data suggest that conditions associated with diminished peptidase activity could result in enhanced responses to stimuli which cause the release of endogenous substance P.

Serum and tissue angiotensin-converting enzyme in patients with alopecia areata.

PubMed

Fahim, Shabnam; Montazer, Fatemeh; Tohidinik, Hamid Reza; Naraghi, Zahra Safaei; Abedini, Robabeh; Nasimi, Maryam; Ghandi, Narges

2018-03-27

Alopecia areata is an immune-dependent disorder characterized by the interaction of T-lymphocytes with follicular antigens. Recent studies have shown the existence of a local renin-angiotensin system in the skin, where angiotensin-converting enzyme (ACE) plays a role in autoimmunity and inflammation. The objective of this study was to evaluate serum and tissue ACE activity in patients with alopecia areata. This case-control study was conducted on patients with alopecia areata and healthy controls. Serum and tissue ACE activity were assessed and compared between the two groups. Twenty-five alopecia areata patients (60% male, mean age 32.1 ± 9.9 years) and 24 controls (50% male, mean age 37.4 ± 8.8 years) were included. Mean serum ACE activity was 52.1 ± 9 U/L in cases and 55.3 ± 14.7 U/L in controls (P = 0.37). Tissue ACE activity was significantly lower in cases in all parts of the skin i.e. epidermis (P = 0.016), follicular epithelium (P = 0.004), and endothelium (P = 0.037). Among cases, serum ACE activity was significantly higher in patients with more severe disease (P = 0.030), nonpatchy alopecia areata (alopecia universalis; ophiasis, patchy and ophiasis, diffuse) (P = 0.029), and with nail involvement (P = 0.027). The sample size was too small to draw definite conclusions. Further, most of the patients had only mild or moderate alopecia areata. Unlike in some other inflammatory diseases, the tissue level of ACE seems to be significantly lower in alopecia areata compared to normal controls. Serum ACE was significantly higher in patients with more severe disease.

S81L and G170R mutations causing Primary Hyperoxaluria type I in homozygosis and heterozygosis: an example of positive interallelic complementation

PubMed Central

Montioli, Riccardo; Roncador, Alessandro; Oppici, Elisa; Mandrile, Giorgia; Giachino, Daniela Francesca; Cellini, Barbara; Borri Voltattorni, Carla

2014-01-01

Primary Hyperoxaluria type I (PH1) is a rare disease due to the deficit of peroxisomal alanine:glyoxylate aminotransferase (AGT), a homodimeric pyridoxal-5′-phosphate (PLP) enzyme present in humans as major (Ma) and minor (Mi) allele. PH1-causing mutations are mostly missense identified in both homozygous and compound heterozygous patients. Until now, the pathogenesis of PH1 has been only studied by approaches mimicking homozygous patients, whereas the molecular aspects of the genotype-enzymatic-clinical phenotype relationship in compound heterozygous patients are completely unknown. Here, for the first time, we elucidate the enzymatic phenotype linked to the S81L mutation on AGT-Ma, relative to a PLP-binding residue, and how it changes when the most common mutation G170R on AGT-Mi, known to cause AGT mistargeting without affecting the enzyme functionality, is present in the second allele. By using a bicistronic eukaryotic expression vector, we demonstrate that (i) S81L-Ma is mainly in its apo-form and has a significant peroxisomal localization and (ii) S81L and G170R monomers interact giving rise to the G170R-Mi/S81L-Ma holo-form, which is imported into peroxisomes and exhibits an enhanced functionality with respect to the parental enzymes. These data, integrated with the biochemical features of the heterodimer and the homodimeric counterparts in their purified recombinant form, (i) highlight the molecular basis of the pathogenicity of S81L-Ma and (ii) provide evidence for a positive interallelic complementation between the S81L and G170R monomers. Our study represents a valid approach to investigate the molecular pathogenesis of PH1 in compound heterozygous patients. PMID:24990153

Genetic Variants of Angiotensin-Converting Enzyme Are Linked to Autism: A Case-Control Study.

PubMed

Firouzabadi, Negar; Ghazanfari, Nima; Alavi Shoushtari, Ali; Erfani, Nasrallah; Fathi, Farshid; Bazrafkan, Mozhdeh; Bahramali, Ehsan

2016-01-01

Autism is a disease of complex nature with a significant genetic component. The importance of renin-angiotensin system (RAS) elements in cognition and behavior besides the interaction of angiotensin II (Ang II), the main product of angiotensin-converting enzyme (ACE), with neurotransmitters in CNS, especially dopamine, proposes the involvement of RAS in autism. Since the genetic architecture of autism has remained elusive, here we postulated that genetic variations in RAS are associated with autism. Considering the relation between the three polymorphisms of ACE (I/D, rs4343 and rs4291) with the level of ACE activity, we have investigated this association with autism, in a case-control study. Genotype and allele frequencies of polymorphisms were determined in DNAs extracted from venous blood of 120 autistic patients and their age and sex-matched healthy controls, using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) methods. There were strong associations between both DD genotype of ACE I/D and the D allele, with autism (P = 0.006, OR = 2.9, 95% CI = 1.64-5.13 and P = 0.006, OR = 2.18, 95% CI = 1.37-3.48 respectively). Furthermore, a significant association between the G allele of rs4343 and autism was observed (P = 0.006, OR = 1.84, 95%CI = 1.26-2.67). Moreover, haplotype analysis revealed an association between DTG haplotype and autism (P = 0.008). Our data suggests the involvement of RAS genetic diversity in increasing the risk of autism.

Quantitative metabolome analysis profiles activation of glutaminolysis in glioma with IDH1 mutation.

PubMed

Ohka, Fumiharu; Ito, Maki; Ranjit, Melissa; Senga, Takeshi; Motomura, Ayako; Motomura, Kazuya; Saito, Kaori; Kato, Keiko; Kato, Yukinari; Wakabayashi, Toshihiko; Soga, Tomoyoshi; Natsume, Atsushi

2014-06-01

Isocitrate dehydrogenase 1 (IDH1), which localizes to the cytosol and peroxisomes, catalyzes the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG) and in parallel converts NADP(+) to NADPH. IDH1 mutations are frequently detected in grades 2-4 gliomas and in acute myeloid leukemias (AML). Mutations of IDH1 have been identified at codon 132, with arginine being replaced with histidine in most cases. Mutant IDH1 gains novel enzyme activity converting α-KG to D-2-hydroxyglutarate (2-HG) which acts as a competitive inhibitor of α-KG. As a result, the activity of α-KG-dependent enzyme is reduced. Based on these findings, 2-HG has been proposed to be an oncometabolite. In this study, we established HEK293 and U87 cells that stably expressed IDH1-WT and IDH1-R132H and investigated the effect of glutaminase inhibition on cell proliferation with 6-diazo-5-oxo-L-norleucine (DON). We found that cell proliferation was suppressed in IDH1-R132H cells. The addition of α-KG restored cell proliferation. The metabolic features of 33 gliomas with wild type IDH1 (IDH1-WT) and with IDH1-R132H mutation were examined by global metabolome analysis using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). We showed that the 2-HG levels were highly elevated in gliomas with IDH1-R132H mutation. Intriguingly, in gliomas with IDH1-R132H, glutamine and glutamate levels were significantly reduced which implies replenishment of α-KG by glutaminolysis. Based on these results, we concluded that glutaminolysis is activated in gliomas with IDH1-R132H mutation and that development of novel therapeutic approaches targeting activated glutaminolysis is warranted.

Massive Thermal Acceleration of the Emergence of Primordial Chemistry, the Incidence of Spontaneous Mutation, and the Evolution of Enzymes*

PubMed Central

Wolfenden, Richard

2014-01-01

Kelvin considered it unlikely that sufficient time had elapsed on the earth for life to have reached its present level of complexity. In the warm surroundings in which life first appeared, however, elevated temperatures would have reduced the kinetic barriers to reaction. Recent experiments disclose the profound extent to which very slow reactions are accelerated by elevated temperatures, collapsing the time that would have been required for early events in primordial chemistry before the advent of enzymes. If a primitive enzyme, like model catalysts and most modern enzymes, accelerated a reaction by lowering its enthalpy of activation, then the rate enhancement that it produced would have increased automatically as the environment cooled, quite apart from any improvements in catalytic activity that arose from mutation and natural selection. The chemical events responsible for spontaneous mutation are also highly sensitive to temperature, furnishing an independent mechanism for accelerating evolution. PMID:25210030

Molecular diversity of tuliposide B-converting enzyme in tulip (Tulipa gesneriana): identification of the root-specific isozyme.

PubMed

Nomura, Taiji; Ueno, Ayaka; Ogita, Shinjiro; Kato, Yasuo

2017-06-01

6-Tuliposide B (PosB) is a glucose ester accumulated in tulip (Tulipa gesneriana) as a major secondary metabolite. PosB serves as the precursor of the antimicrobial lactone tulipalin B (PaB), which is formed by PosB-converting enzyme (TCEB). The gene TgTCEB1, encoding a TCEB, is transcribed in tulip pollen but scarcely transcribed in other tissues (e.g. roots) even though those tissues show high TCEB activity. This led to the prediction of the presence of a TCEB isozyme with distinct tissue specificity. Herein, we describe the identification of the TgTCEB-R gene from roots via native enzyme purification; this gene is a paralog of TgTCEB1. Recombinant enzyme characterization verified that TgTCEB-R encodes a TCEB. Moreover, TgTCEB-R was localized in tulip plastids, as found for pollen TgTCEB1. TgTCEB-R is transcribed almost exclusively in roots, indicating a tissue preference for the transcription of TCEB isozyme genes.

A human lung mast cell chymotrypsin-like enzyme. Identification and partial characterization.

PubMed

Wintroub, B U; Kaempfer, C E; Schechter, N M; Proud, D

1986-01-01

We have used a high performance liquid chromatography assay, which detects chymotryptic cleavage of the phe8-his9 bond of angiotensin I to yield angiotensin II, in order to examine human lung mast cells for the presence of chymotryptic activity. Mast cells, purified from human lung by enzymatic dispersion, countercurrent elutriation, and Percoll gradient centrifugation, were lysed or challenged with goat anti-human IgE. In multiple experiments angiotensin II-converting activity was detected in lysates of 10-99% pure mast cell preparations. Regression analysis of net percent release values of histamine and the angiotensin I-converting activity from dose-response experiments demonstrated a correlation between the two parameters, indicating that the chymotrypsin-like enzyme is a constituent of the mast cell secretory granule. The chymotryptic activity was completely inhibited by 10(-3) M phenylmethylsulfonylfluoride but not by 10(-3) M Captopril, and the pH optimum of activity was 7.5-9.5. Gel filtration of released material separated the activity from tryptase and demonstrated an approximate molecular weight of 30-35,000. The mast cell enzyme, like a human skin chymotrypsin-like proteinase, can be distinguished from leukocyte cathepsin G by lack of susceptibility to inhibition by bovine pancreatic trypsin inhibitor. Thus, an enzyme with limited chymotryptic specificity is present in human lung mast cells. The Michaelis constant of the enzyme for angiotensin I of 6.0 X 10(-5) M is similar to that of endothelial cell angiotensin-converting enzyme and is consistent with a reaction of physiologic importance.

Angiotensin-converting enzyme inhibitors in patients with coronary artery disease and absence of heart failure or left ventricular systolic dysfunction: an overview of long-term randomized controlled trials.

PubMed

Danchin, Nicolas; Cucherat, Michel; Thuillez, Christian; Durand, Eric; Kadri, Zena; Steg, Philippe G

2006-04-10

Results of randomized trials of angiotensin-converting enzyme inhibitors in patients with coronary artery disease (CAD) and preserved left ventricular function are conflicting. We undertook this study to determine whether long-term prescription of angiotensin-converting enzyme inhibitors decreases major cardiovascular events and mortality in patients who have CAD and no evidence of left ventricular systolic dysfunction. We searched MEDLINE, EMBASE, and IPA databases, the Cochrane Controlled Trials Register (1990-2004), and reports from scientific meetings (2003-2004), and we reviewed secondary sources. Search terms included angiotensin-converting enzyme inhibitors, coronary artery disease, randomi(s)zed controlled trials, clinical trials, and myocardial infarction. Eligible studies included randomized controlled trials in patients who had CAD and no heart failure or left ventricular dysfunction, with follow-up omicronf 2 years or longer. Of 1146 publications screened, 7 met our selection criteria and included a total of 33 960 patients followed up for a mean of 4.4 years. Five trials included only patients with documented CAD. One trial included patients with documented CAD (80%) or patients who had diabetes mellitus and 1 or more additional risk factors, and another trial included patients who had CAD, a history of transient ischemic attack, or intermittent claudication. Treatment with angiotensin-converting enzyme inhibitors decreased overall mortality (odds ratio, 0.86; 95% confidence interval, 0.79-0.93), cardiovascular mortality (odds ratio, 0.81; 95% confidence interval, 0.73-0.90), myocardial infarction (odds ratio, 0.82; 95% confidence interval, 0.75-0.89), and stroke (odds ratio, 0.77; 95% confidence interval, 0.66-0.88). Other end points, including resuscitation after cardiac arrest, myocardial revascularization, and hospitalization because of heart failure, were also reduced. Angiotensin-converting enzyme inhibitors reduce total mortality and major

Major amyloid-β-degrading enzymes, endothelin-converting enzyme-2 and neprilysin, are expressed by distinct populations of GABAergic interneurons in hippocampus and neocortex.

PubMed

Pacheco-Quinto, Javier; Eckman, Christopher B; Eckman, Elizabeth A

2016-12-01

Impaired clearance of amyloid-β peptide (Aβ) has been postulated to significantly contribute to the amyloid accumulation typical of Alzheimer's disease. Among the enzymes known to degrade Aβ in vivo are endothelin-converting enzyme (ECE)-1, ECE-2, and neprilysin (NEP), and evidence suggests that they regulate independent pools of Aβ that may be functionally significant. To better understand the differential regulation of Aβ concentration by its physiological degrading enzymes, we characterized the cell and region-specific expression pattern of ECE-1, ECE-2, and NEP by in situ hybridization and immunohistochemistry in brain areas relevant to Alzheimer's disease. In contrast to the broader distribution of ECE-1, ECE-2 and NEP were found enriched in GABAergic neurons. ECE-2 was majorly expressed by somatostatin-expressing interneurons and was active in isolated synaptosomes. NEP messenger RNA was found mainly in parvalbumin-expressing interneurons, with NEP protein localized to perisomatic parvalbuminergic synapses. The identification of somatostatinergic and parvalbuminergic synapses as hubs for Aβ degradation is consistent with the possibility that Aβ may have a physiological function related to the regulation of inhibitory signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

EI-2128-1, a novel interleukin-1beta converting enzyme inhibitor produced by Penicillium sp. E-2128.

PubMed

Koizumi, Fumito; Agatsuma, Tsutomu; Ando, Katsuhiko; Kondo, Hidemasa; Saitoh, Yutaka; Matsuda, Yuzuru; Nakanishi, Satoshi

2003-11-01

EI-2128-1, a novel interleukin-1beta converting enzyme (ICE) inhibitor, was isolated from the culture broths of Penicillium sp. E-2128. EI-2128-1 selectively inhibited human recombinant ICE activity with IC50 value of 0.59 microM, without inhibiting elastase and cathepsin B. EI-2128-1 also inhibited mature interleukin-1beta secretion from THP-1 cells induced by LPS with IC50 value of 0.28 microM.

Distinct signatures for mutator sensitivity of lacZ reversions and for the spectrum of lacI/lacO forward mutations on the chromosome of nondividing Escherichia coli.

PubMed Central

Bharatan, Shanti M; Reddy, Manjula; Gowrishankar, J

2004-01-01

A conditional lethal galE(Ts)-based strategy was employed in Escherichia coli, first to eliminate all growth-associated chromosomal reversions in lacZ or forward mutations in lacI/lacO by incubation at the restrictive temperature and subsequently to recover (as papillae) spontaneous mutations that had arisen in the population of nondividing cells after shift to the permissive temperature. Data from lacZ reversion studies in mutator strains indicated that the products of all genes for mismatch repair (mutHLS, dam, uvrD), of some for oxidative damage repair (mutMT), and of that for polymerase proofreading (dnaQ) are required in dividing cells; some others for oxidative damage repair (mutY, nth nei) are required in both dividing and nondividing cells; and those for alkylation damage repair (ada ogt) are required in nondividing cells. The spectrum of lacI/lacO mutations in nondividing cells was distinguished both by lower frequencies of deletions and IS1 insertions and by the unique occurrence of GC-to-AT transitions at lacO +5. In the second approach to study mutations that had occurred in nondividing cells, lacI/lacO mutants were selected as late-arising papillae from the lawn of a galE+ strain; once again, transitions at lacO +5 were detected among the mutants that had been obtained from populations initially grown on poor carbon sources such as acetate, palmitate, or succinate. Our results indicate that the lacO +5 site is mutable only in nondividing cells, one possible mechanism for which might be that random endogenous alkylation (or oxidative) damage to DNA in these cells is efficiently corrected by the Ada Ogt (or Nth Nei) repair enzymes at most sites but not at lacO +5. Furthermore, the late-arising papillae from the second approach were composed almost exclusively of dominant lacI/lacO mutants. This finding lends support to "instantaneous gratification" models in which a spontaneous lesion, occurring at a random site in DNA of a nondividing cell, is most

Effect of SQ29,852, a new angiotensin converting enzyme (ACE) inhibitor with a phosphonic acid group, on the activity of angiotensin converting enzyme from human kidney.

PubMed

Hiwada, K; Inoue, Y; Kokubu, T

1990-01-01

1. An in vitro experiment was carried out to compare the inhibitory effect of SQ29,852 on human renal angiotensin converting enzyme (ACE) with those of captopril, enalapril and enalaprilat. 2. SQ29,852 strongly inhibited human renal ACE; its IC50 value was 1.5 x 10(-8) M. In terms of the IC50, SQ29,852's efficacy was about 1/10 of that of captopril and 1/28 of that of enalaprilat, but it was about 14 times more potent than enalapril. 3. SQ29,852 showed no inhibitory effects on cathepsin D, urinary kallikrein, renal renin, pepsin, trypsin and chymotrypsin. Its ACE-specificity was higher than that of captopril. 4. ACE inhibition by SQ29,852 was shown to be competitive, as revealed by Lineweaver-Burk plots. The affinity of SQ29,852 to ACE was shown to be high by a Ki value of 1.2 x 10(-8) M.

Inhibition of Angiotensin-Converting Enzyme Activity by Flavonoids: Structure-Activity Relationship Studies

PubMed Central

Guerrero, Ligia; Castillo, Julián; Quiñones, Mar; Garcia-Vallvé, Santiago; Arola, Lluis; Pujadas, Gerard; Muguerza, Begoña

2012-01-01

Previous studies have demonstrated that certain flavonoids can have an inhibitory effect on angiotensin-converting enzyme (ACE) activity, which plays a key role in the regulation of arterial blood pressure. In the present study, 17 flavonoids belonging to five structural subtypes were evaluated in vitro for their ability to inhibit ACE in order to establish the structural basis of their bioactivity. The ACE inhibitory (ACEI) activity of these 17 flavonoids was determined by fluorimetric method at two concentrations (500 µM and 100 µM). Their inhibitory potencies ranged from 17 to 95% at 500 µM and from 0 to 57% at 100 µM. In both cases, the highest ACEI activity was obtained for luteolin. Following the determination of ACEI activity, the flavonoids with higher ACEI activity (i.e., ACEI >60% at 500 µM) were selected for further IC50 determination. The IC50 values for luteolin, quercetin, rutin, kaempferol, rhoifolin and apigenin K were 23, 43, 64, 178, 183 and 196 µM, respectively. Our results suggest that flavonoids are an excellent source of functional antihypertensive products. Furthermore, our structure-activity relationship studies show that the combination of sub-structures on the flavonoid skeleton that increase ACEI activity is made up of the following elements: (a) the catechol group in the B-ring, (b) the double bond between C2 and C3 at the C-ring, and (c) the cetone group in C4 at the C-ring. Protein-ligand docking studies are used to understand the molecular basis for these results. PMID:23185345

Binding affinity and adhesion force of organophosphate hydrolase enzyme with soil particles related to the isoelectric point of the enzyme.

PubMed

Islam, Shah Md Asraful; Yeasmin, Shabina; Islam, Md Saiful; Islam, Md Shariful

2017-07-01

The binding affinity of organophosphate hydrolase enzyme (OphB) with soil particles in relation to the isoelectric point (pI) was studied. Immobilization of OphB with soil particles was observed by confocal microscopy, Fourier transform infrared spectroscopy (FT-IR), and Atomic force microscopy (AFM). The calculated pI of OphB enzyme was increased from 8.69 to 8.89, 9.04 and 9.16 by the single, double and triple mutant of OphB enzyme, respectively through the replacement of negatively charged aspartate with positively charged histidine. Practically, the binding affinity was increased to 5.30%, 11.50%, and 16.80% for single, double and triple mutants, respectively. In contrast, enzyme activity of OphB did not change by the mutation of the enzyme. On the other hand, adhesion forces were gradually increased for wild type OphB enzyme (90 pN) to 96, 100 and 104 pN for single, double and triple mutants of OphB enzyme, respectively. There was an increasing trend of binding affinity and adhesion force by the increase of isoelectric point (pI) of OphB enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

Mutant α-galactosidase A enzymes identified in Fabry disease patients with residual enzyme activity: biochemical characterization and restoration of normal intracellular processing by 1-deoxygalactonojirimycin

PubMed Central

Ishii, Satoshi; Chang, Hui-Hwa; Kawasaki, Kunito; Yasuda, Kayo; Wu, Hui-Li; Garman, Scott C.; Fan, Jian-Qiang

2007-01-01

Fabry disease is a lysosomal storage disorder caused by the deficiency of α-Gal A (α-galactosidase A) activity. In order to understand the molecular mechanism underlying α-Gal A deficiency in Fabry disease patients with residual enzyme activity, enzymes with different missense mutations were purified from transfected COS-7 cells and the biochemical properties were characterized. The mutant enzymes detected in variant patients (A20P, E66Q, M72V, I91T, R112H, F113L, N215S, Q279E, M296I, M296V and R301Q), and those found mostly in mild classic patients (A97V, A156V, L166V and R356W) appeared to have normal Km and Vmax values. The degradation of all mutants (except E59K) was partially inhibited by treatment with kifunensine, a selective inhibitor of ER (endoplasmic reticulum) α-mannosidase I. Metabolic labelling and subcellular fractionation studies in COS-7 cells expressing the L166V and R301Q α-Gal A mutants indicated that the mutant protein was retained in the ER and degraded without processing. Addition of DGJ (1-deoxygalactonojirimycin) to the culture medium of COS-7 cells transfected with a large set of missense mutant α-Gal A cDNAs effectively increased both enzyme activity and protein yield. DGJ was capable of normalizing intracellular processing of mutant α-Gal A found in both classic (L166V) and variant (R301Q) Fabry disease patients. In addition, the residual enzyme activity in fibroblasts or lymphoblasts from both classic and variant hemizygous Fabry disease patients carrying a variety of missense mutations could be substantially increased by cultivation of the cells with DGJ. These results indicate that a large proportion of mutant enzymes in patients with residual enzyme activity are kinetically active. Excessive degradation in the ER could be responsible for the deficiency of enzyme activity in vivo, and the DGJ approach may be broadly applicable to Fabry disease patients with missense mutations. PMID:17555407

An investigation of the concomitant use of angiotensin-converting enzyme inhibitors, non-steroidal anti-inflammatory drugs and diuretics.

PubMed

Bucsa, C; Moga, D C; Farcas, A; Mogosan, C; Dumitrascu, D L

2015-08-01

To determine in retrospective data the prevalence at hospital discharge of co-prescribing angiotensin-converting enzyme inhibitors (ACE-I) and non-steroidal anti-inflammatory drugs (NSAIDs) and ACE-I/NSAIDs and diuretics and to identify factors associated with the co-prescription. Secondary, we evaluated the extent of serum creatinine and potassium monitoring in patients treated with ACE-I and these associations and determined the prevalence of values above the upper normal limit (UNL) in monitored patients. Hospitalized patients with ACE-I in their therapy at discharge were included in 3 groups as follows: ACE-I, DT (double therapy with ACE-I and NSAIDs) and TT (triple therapy with ACE-I, NSAIDs and diuretics) groups. We evaluated differences on demographic characteristics, co-morbidities, medications, laboratory monitoring and quantified the patients with serum creatinine and potassium levels above the UNL using descriptive statistics. Logistic regression analysis with backward elimination was performed to identify significant predictors of combination therapy. Of 9960 admitted patients, 1214 were prescribed ACE-I, 40 were prescribed ACE-I/NSAIDs and 22 were prescribed ACE-I/NSAIDs/diuretics (3.13% and 1.72%, respectively, of the patients prescribed with ACE-I). Serum creatinine and potassium were monitored for the great majority of patients from all groups. The highest percentage of hyperkalemia was found in the DT group (10% of the patients) and of serum creatinine above UNL in the TT group (45.45%). The logistic regression final model showed that younger patients and monitoring for potassium were significantly associated with combination therapy. The prevalence of patients receiving DT/TT was relatively low and their monitoring during hospitalization was high. Factors associated with the combinations were younger patients and patients not tested for serum potassium.

The influence of angiotensin-converting enzyme inhibitors on the aorta elastin metabolism in diet-induced hypercholesterolaemia in rabbits.

PubMed

Wojakowski, W; Gminski, J; Siemianowicz, K; Goss, M; Machalski, M

2001-03-01

Aortic elastin turnover is significantly accelerated in atherosclerosis, partly because of activation of the renin-angiotensin-aldosterone system caused by hypercholesterolaemia. We postulated that angiotensin-converting enzyme inhibitors (ACE-I) prevent the aortic elastin loss in experimental hypercholesterolaemia. Two doses of ACE-I (captopril, enalapril and quinapril) were used: a dose equivalent to that applied to human subjects and a dose 10 times higher. We found that the increase in serum and aortic elastolytic activity in cholesterol-fed rabbits was prevented by high-dose captopril. The elastin content in aorta homogenates from cholesterol-fed rabbits was significantly decreased. The higher dose of captopril, but no other ACE-I, prevented this decrease in aortic elastin content. In cholesterol-fed rabbits the elastin-bound calcium content was significantly elevated. The higher doses of captopril and enalapril lowered the elastin-bound calcium content. In serum and aortic homogenates of cholesterol-fed rabbits, ACE activity was elevated by 15% and 77%, respectively. Both doses of captopril, enalapril and quinapril prevented this cholesterol-induced increase in serum and aortic ACE activity. We conclude that: 1) administration of captopril at doses 10 times higher than those used in humans prevents hypercholesterolaemia increased aortic elastin loss. 2) higher doses of captopril and enalapril prevent the hypercholesterolaemia-induced increase in aortic elastin-bound calcium.

Effects of helix and fingertip mutations on the thermostability of xyn11A investigated by molecular dynamics simulations and enzyme activity assays.

PubMed

Sutthibutpong, Thana; Rattanarojpong, Triwit; Khunrae, Pongsak

2017-12-04

Local conformational changes and global unfolding pathways of wildtype xyn11A recombinant and its mutated structures were studied through a series of atomistic molecular dynamics (MD) simulations, along with enzyme activity assays at three incubation temperatures to investigate the effects of mutations at three different sites to the thermostability. The first mutation was to replace an unstable negatively charged residue at a surface beta turn near the active site (D32G) by a hydrophobic residue. The second mutation was to create a disulphide bond (S100C/N147C) establishing a strong connection between an alpha helix and a distal beta hairpin associated with the thermally sensitive Thumb loop, and the third mutation add an extra hydrogen bond (A155S) to the same alpha helix. From the MD simulations performed, MM/PBSA energy calculations of the unfolding energy were in a good agreement with the enzyme activities measured from the experiment, as all mutated structures demonstrated the improved thermostability, especially the S100C/N147C proved to be the most stable mutant both by the simulations and the experiment. Local conformational analysis at the catalytic sites and the xylan access region also suggested that mutated xyn11A structures could accommodate xylan binding. However, the analysis of global unfolding pathways showed that structural disruptions at the beta sheet regions near the N-terminal were still imminent. These findings could provide the insight on the molecular mechanisms underlying the enhanced thermostability due to mutagenesis and changes in the protein unfolding pathways for further protein engineering of the GH11 family xylanase enzymes.

Expression of androgen receptor through androgen-converting enzymes is associated with biological aggressiveness in prostate cancer.

PubMed

Wako, K; Kawasaki, T; Yamana, K; Suzuki, K; Jiang, S; Umezu, H; Nishiyama, T; Takahashi, K; Hamakubo, T; Kodama, T; Naito, M

2008-04-01

The association between the expression of androgen receptor (AR) or androgen-converting enzymes and malignant potential in prostate cancer (PCa) was examined. PCa specimens from 44 cases of stage II, 10 cases of stage III, four cases of stage IV and two recurrent cases were semi-quantitatively studied with immunohistochemistry for AR and androgen-converting enzymes. The expression scores for AR, 5alpha-reductase type 1 (SRD5A1), 5alpha-reductase type 2 (SRD5A2), and aldo-keto reductase family 1 member C3 (AKR1C3) in the metastatic lesion of stage IV or recurrent cancer (n = 6) were 284.2 (30.1), 300 (0.0), 279.2 (51) and 254.2 (74.9), respectively; these scores were significantly higher than the respective scores of 121.8 (82.1), 135.1 (59.7), 167.0 (66.4) and 150.5 (62.8) for stage II and III cancer (n = 54) (p<0.001, p<0.001, p = 0.002 and p = 0.018, respectively). The expression scores for AR and SRD5A1 in stage II and III cancer with Gleason score 7 (n = 19) were 128.7 (72.3) and 150.5 (52.9); these were significantly higher than the scores of 78.8 (67.2) and 100.0 (39.6), respectively, for cancers with a Gleason score of < or =6 (n = 20) (p = 0.032 and p = 0.002, respectively). The expression scores for AR, SRD5A1 and AKR1C3 in stage II and III cancer with primary Gleason pattern > or =4 (n = 21) were 158.1 (84.3), 158.3 (61.1) and 173.8 (64.8); these were significantly higher than the scores of 98.6 (72.8), 120.3 (54.7) and 135.6 (57.6), respectively, for cancers with primary Gleason pattern < or =3 (n = 33) (p = 0.011, p = 0.026 and p = 0.034, respectively). Within Gleason score 9 cancer, the expression scores for AR and SRD5A1 in the primary lesion of stage IV (n = 3) were 276.7 (5.8) and 283.3 (28.9); these scores were significantly higher than the scores of 182.1 (86.0) and 140.0 (56.6), respectively, for stage II and III cancer (n = 7) (p = 0.027 and p = 0.001, respectively). Both AR and androgen-converting enzymes were upregulated in high-grade or

Characterization of two Streptomyces enzymes that convert ferulic acid to vanillin.

PubMed

Yang, Wenwen; Tang, Hongzhi; Ni, Jun; Wu, Qiulin; Hua, Dongliang; Tao, Fei; Xu, Ping

2013-01-01

Production of flavors from natural substrates by microbial transformation has become a growing and expanding field of study over the past decades. Vanillin, a major component of vanilla flavor, is a principal flavoring compound used worldwide. Streptomyces sp. strain V-1 is known to be one of the most promising microbial producers of natural vanillin from ferulic acid. Although identification of the microbial genes involved in the biotransformation of ferulic acid to vanillin has been previously reported, purification and detailed characterization of the corresponding enzymes with important functions have rarely been studied. In this study, we isolated and identified 2 critical genes, fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, which are involved in the vanillin production from ferulic acid. Both genes were heterologously expressed in Escherichia coli, and the resting cell reactions for converting ferulic acid to vanillin were performed. The corresponding crucial enzymes, Fcs and Ech, were purified for the first time and the enzymatic activity of each purified protein was studied. Furthermore, Fcs was comprehensively characterized, at an optimal pH of 7.0 and temperature of 30°C. Kinetic constants for Fcs revealed the apparent Km, kcat, and Vmax values to be 0.35 mM, 67.7 s(-1), and 78.2 U mg(-1), respectively. The catalytic efficiency (kcat/Km) value of Fcs was 193.4 mM(-1) s(-1) for ferulic acid. The characterization of Fcs and Ech may be helpful for further research in the field of enzymatic engineering and metabolic regulation.

Mitochondrial respiratory chain enzyme assay and DNA analysis in peripheral blood leukocytes for the etiological study of Chinese children with Leigh syndrome due to complex I deficiency.

PubMed

Ma, Yan Yan; Wu, Tong Fei; Liu, Yu Peng; Wang, Qiao; Li, Xi Yuan; Zhang, Yao; Song, Jin Qing; Wang, Yu Jie; Yang, Yan Ling

2013-02-01

Mitochondrial respiratory chain complex I enzyme deficiency is the most commonly seen mitochondrial respiratory chain disorder. Although screening and diagnostic methods are available overseas, clinically feasible diagnostic methods have not yet been established in China. In this study, four Chinese boys with Leigh syndrome due to complex I deficiency were diagnosed by mitochondrial respiratory chain enzyme assay and DNA analysis using peripheral blood leukocytes. Four patients were admitted at the age of 5-14 years because of unexplained progressive neuromuscular symptoms, including motor developmental delay or regression, weakness, and seizures. Their cranial magnetic resonance imaging revealed typical finding as Leigh syndrome. Peripheral leukocyte mitochondrial respiratory chain complex I activities were found decreased to 9.6-33.1 nmol/min/mg mitochondrial protein(control 44.0 ± 5.4 nmol/min/mg). The ratios of complex I to citrate synthase activity were also decreased (8.9-19.8% in patients vs. control 48 ± 11%). Three mtDNA mutations were identified from three out of four patients, supporting the diagnosis of complex I deficiency. Point mutations m.10191T>C in mitochondrial ND3 gene, m.13513G>A in ND5 gene and m.14,453G>A in ND6 gene were detected in three patients.

Effects of angiotensin-converting enzyme inhibitor versus valsartan on cellular signaling events in heart transplant.

PubMed

White, Michel; Ross, Heather; Levesque, Sylvie; Whittom, Lucette; Pelletier, Guy B; Racine, Normand; Meloche, Sylvain; Voisin, Laure

2009-05-01

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) provide similar biologic effects in model systems and similar clinical impacts in humans. The changes in the cardiac angiotensin system signaling pathways in the human heart in response to ACE inhibitors versus ARBs have been incompletely studied. To investigate the effects of ACE inhibitors versus valsartan on the angiotensin II signal transduction pathways in the transplanted human heart. Twenty-seven stable cardiac transplant recipients were randomized to remain on ACE inhibitor therapy (n = 8) or to receive valsartan (n = 19). Two additional endomyocardial biopsy samples were obtained at baseline and after 9 months of therapy. The expression of cardiac angiotensin type I and II receptors and atrial natriuretic factor (ANF) was measured by quantitative polymerase chain reaction. The expression and phosphorylation levels of selected signal transduction pathways were analyzed by immunoblotting. The mean dose of valsartan was 114 +/- 41 mg/day. The use of valsartan resulted in a similar impact on blood pressure and biochemistry profile. There were no significant changes in the expression of angiotensin type I and II receptors and ANF with valsartan. Similarly, no significant changes in the expression and phosphorylation of Jun N-terminal kinase, extracellular signal-regulated kinase 1 and 2, and p38 mitogen-activated protein kinases or AKT, and mammalian target of rapamycin was observed in the valsartan-treated group. Valsartan use is associated with similar clinical and molecular cardiac effects as ACE inhibitor therapy in stable long-term cardiac transplant recipients.

Tuning and Switching Enantioselectivity of Asymmetric Carboligation in an Enzyme through Mutational Analysis of a Single Hot Spot.

PubMed

Wechsler, Cindy; Meyer, Danilo; Loschonsky, Sabrina; Funk, Lisa-Marie; Neumann, Piotr; Ficner, Ralf; Brodhun, Florian; Müller, Michael; Tittmann, Kai

2015-12-01

Enantioselective bond making and breaking is a hallmark of enzyme action, yet switching the enantioselectivity of the reaction is a difficult undertaking, and typically requires extensive screening of mutant libraries and multiple mutations. Here, we demonstrate that mutational diversification of a single catalytic hot spot in the enzyme pyruvate decarboxylase gives access to both enantiomers of acyloins acetoin and phenylacetylcarbinol, important pharmaceutical precursors, in the case of acetoin even starting from the unselective wild-type protein. Protein crystallography was used to rationalize these findings and to propose a mechanistic model of how enantioselectivity is controlled. In a broader context, our studies highlight the efficiency of mechanism-inspired and structure-guided rational protein design for enhancing and switching enantioselectivity of enzymatic reactions, by systematically exploring the biocatalytic potential of a single hot spot. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ocular Inserts for Sustained Release of the Angiotensin-Converting Enzyme 2 Activator, Diminazene Aceturate, to Treat Glaucoma in Rats

PubMed Central

Nogueira, José Carlos; Fulgêncio, Gustavo de Oliveira; Ribeiro, Tatiana Gomes; Castilho, Rachel Oliveira; Yoshida, Maria Irene; Fuscaldi, Leonardo Lima; Fernandes, Simone Odília Antunes; Cardoso, Valbert Nascimento; Cronemberger, Sebastião; Faraco, André Augusto Gomes; Ferreira, Anderson José

2015-01-01

The aim of this study was to develop and evaluate the effects of chitosan inserts for sustained release of the angiotensin-converting enzyme 2 (ACE2) activator, diminazene aceturate (DIZE), in experimental glaucoma. Monolayer DIZE loaded inserts (D+I) were prepared and characterized through swelling, attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and in vitro drug release. Functionally, the effects of D+I were tested in glaucomatous rats. Glaucoma was induced by weekly injections of hyaluronic acid (HA) into the anterior chamber and intraocular pressure (IOP) measurements were performed. Retinal ganglion cells (RGC) and optic nerve head cupping were evaluated in histological sections. Biodistribution of the drug was accessed by scintigraphic images and ex vivo radiation counting. We found that DIZE increased the swelling index of the inserts. Also, it was molecularly dispersed and interspersed in the polymeric matrix as a freebase. DIZE did not lose its chemical integrity and activity when loaded in the inserts. The functional evaluation demonstrated that D+I decreased the IOP and maintained the IOP lowered for up to one month (last week: 11.0±0.7 mmHg). This effect of D+I prevented the loss of RGC and degeneration of the optic nerve. No toxic effects in the eyes related to application of the inserts were observed. Moreover, biodistribution studies showed that D+I prolonged the retention of DIZE in the corneal site. We concluded that D+I provided sustained DIZE delivery in vivo, thereby evidencing the potential application of polymeric-based DIZE inserts for glaucoma management. PMID:26204514

Elevated serum angiotensin-converting enzyme (SACE) activity in acute pulmonary histoplasmosis.

PubMed

Davies, S F; Rohrbach, M S; Thelen, V; Kuritsky, J; Gruninger, R; Simpson, M L; DeRemee, R A

1984-03-01

Serum angiotensin-converting enzyme (SACE) levels were measured in 44 subjects six weeks after acute pulmonary histoplasmosis. All patients were infected in a common-source outbreak of histoplasmosis which occurred on one day. All patients had both strictly defined clinical and serologic evidence of infection. The SACE activity was elevated at six weeks compared to normal controls, and seven of the 44 had levels more than 2 SD above the normal mean. SACE levels were also measured at three and 24 weeks after acute infection in a smaller number of the same subjects. Serial observations demonstrated that all subjects (including those with normal and elevated SACE at six weeks) had a rise and fall in SACE activity following symptomatic acute pulmonary histoplasmosis. Our findings suggest that elevated SACE does not reliably separate sarcoidosis from histoplasmosis, although elevations in histoplasmosis are much less common and may occur only briefly following acute pulmonary histoplasmosis. More important, it seems that SACE activity rises acutely in all patients with symptomatic acute histoplasmosis and then falls gradually toward baseline over several months, coinciding temporally with the granulomatous response.

Structural basis of glyphosate resistance resulting from the double mutation Thr97 -> Ile and Pro101 -> Ser in 5-enolpyruvylshikimate-3-phosphate synthase from Escherichia coli.

PubMed

Funke, Todd; Yang, Yan; Han, Huijong; Healy-Fried, Martha; Olesen, Sanne; Becker, Andreas; Schönbrunn, Ernst

2009-04-10

The shikimate pathway enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is the target of the broad spectrum herbicide glyphosate. The genetic engineering of EPSPS led to the introduction of glyphosate-resistant crops worldwide. The genetically engineered corn lines NK603 and GA21 carry distinct EPSPS enzymes. CP4 EPSPS, expressed in NK603 corn and transgenic soybean, cotton, and canola, belongs to class II EPSPS, glyphosate-insensitive variants of this enzyme isolated from certain Gram-positive bacteria. GA21 corn, on the other hand, was created by point mutations of class I EPSPS, such as the enzymes from Zea mays or Escherichia coli, which are sensitive to low glyphosate concentrations. The structural basis of the glyphosate resistance resulting from these point mutations has remained obscure. We studied the kinetic and structural effects of the T97I/P101S double mutation, the molecular basis for GA21 corn, using EPSPS from E. coli. The T97I/P101S enzyme is essentially insensitive to glyphosate (K(i) = 2.4 mm) but maintains high affinity for the substrate phosphoenolpyruvate (PEP) (K(m) = 0.1 mm). The crystal structure at 1.7-A resolution revealed that the dual mutation causes a shift of residue Gly(96) toward the glyphosate binding site, impairing efficient binding of glyphosate, while the side chain of Ile(97) points away from the substrate binding site, facilitating PEP utilization. The single site T97I mutation renders the enzyme sensitive to glyphosate and causes a substantial decrease in the affinity for PEP. Thus, only the concomitant mutations of Thr(97) and Pro(101) induce the conformational changes necessary to produce catalytically efficient, glyphosate-resistant class I EPSPS.

Defective complex I assembly due to C20orf7 mutations as a new cause of Leigh syndrome

PubMed Central

Gerards, M; Sluiter, W; van den Bosch, B J C; de Wit, L E A; Calis, C M H; Frentzen, M; Akbari, H; Schoonderwoerd, K; Scholte, H R; Jongbloed, R J; Hendrickx, A T M; de Coo, I F M

2009-01-01

Background Leigh syndrome is an early onset, progressive, neurodegenerative disorder with developmental and motor skills regression. Characteristic magnetic resonance imaging abnormalities consist of focal bilateral lesions in the basal ganglia and/or the brainstem. The main cause is a deficiency in oxidative phosphorylation due to mutations in an mtDNA or nuclear oxidative phosphorylation gene. Methods and results A consanguineous Moroccan family with Leigh syndrome comprise 11 children, three of which are affected. Marker analysis revealed a homozygous region of 11.5 Mb on chromosome 20, containing 111 genes. Eight possible mitochondrial candidate genes were sequenced. Patients were homozygous for an unclassified variant (p.P193L) in the cardiolipin synthase gene (CRLS1). As this variant was present in 20% of a Moroccan control population and enzyme activity was only reduced to 50%, this could not explain the rare clinical phenotype in our family. Patients were also homozygous for an amino acid substitution (p.L159F) in C20orf7, a new complex I assembly factor. Parents were heterozygous and unaffected sibs heterozygous or homozygous wild type. The mutation affects the predicted S-adenosylmethionine (SAM) dependent methyltransferase domain of C20orf7, possibly involved in methylation of NDUFB3 during the assembly process. Blue native gel electrophoresis showed an altered complex I assembly with only 30–40% of mature complex I present in patients and 70–90% in carriers. Conclusions A new cause of Leigh syndrome can be a defect in early complex I assembly due to C20orf7 mutations. PMID:19542079

Angiotensin-converting Enzyme Inhibition Improves the Effectiveness of Transcutaneous Carbon Dioxide Treatment

PubMed Central

NEMETH, BALAZS; KISS, ISTVAN; JENCSIK, TIMEA; PETER, IVAN; KRESKA, ZITA; KOSZEGI, TAMAS; MISETA, ATTILA; KUSTAN, PETER; BONCZ, IMRE; LACZO, ANDREA; AJTAY, ZENO

2017-01-01

Aim: To study the effect of carbon dioxide (CO2) therapy on the nitric oxide (NO) pathway by monitoring plasma asymmetric dimethylarginine (ADMA) concentrations. Patients and Methods: Forty-seven hypertensive patients who underwent transcutaneous CO2 therapy were enrolled. Thirty healthy individuals were recruited for the control group. Blood samples were taken one hour before, as well as one hour, 24 hours and 3 weeks after the first CO2 treatment. Controls did not undergo CO2 treatment. Plasma ADMA levels were measured by ELISA. Results: ADMA levels decreased significantly one hour after the first CO2 treatment compared to the baseline concentrations (p=0.003). Significantly greater reduction was found among patients in whom angiotensin converting enzyme inhibitors (ACEIs) were administered (p=0.019). Conclusion: The short- and long-term decrease of ADMA levels suggests that CO2 is not only a vasodilator, but also has a beneficial effect on the NO pathway. ACE inhibition seems to enhance the effect of CO2 treatment. PMID:28438873

The angiotensin converting enzyme D allele is an independent risk factor for early onset coronary artery disease.

PubMed

Vaisi-Raygani, Asad; Ghaneialvar, Hori; Rahimi, Zohreh; Nomani, Hamid; Saidi, Mohmadreza; Bahrehmand, Fariborz; Vaisi-Raygani, Aliakbar; Tavilani, Haidar; Pourmotabbed, Tayebeh

2010-10-01

The role of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in early onset coronary artery disease age < 55years (ECAD) is controversial. The aim of this study was to further evaluate the role of this ACE(I/D) gene polymorphism on the risk of premature CAD in patients from western Iran. The ACE(I/D) genotypes were detected by PCR-RFLP in 323 individuals undergoing their first coronary angiography. Patients were placed into two groups: ECAD and late onset CAD age ≥ 55years (LCAD). We found a statistically significant association of the ACE D allele, as homozygous or ACE ID plus DD genotypes (ID+DD), only in the ECAD subjects OR=1.35, p=0.015, OR=3.27, p=0.014, and OR=2.8, p=0.013, respectively. In addition, there was a significant association after adjustment for the absence of history of diabetes, presence of normolipidemia and absence of history of blood pressure [OR 1.38, p=0.017 and 2.35, p=0.02]. Our results indicated that the ACE D allele is a risk factor for early onset of CAD even after correcting for conventional risk factors. The incidence of triple vessel disease was significantly higher in individuals carrying ACE(D/D) genotype in ECAD patients compared to those who carried ACE(I/I) genotype (OR 3.38; p=0.019; 57.5% vs. 42.5%; p=0.013). The presence of D allele of ACE can be important independent risk factor in the onset of CAD patients less than 55 years old in a west population of Iran. Larger collaborative studies are needed to confirm these results. Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Characterization of Two Streptomyces Enzymes That Convert Ferulic Acid to Vanillin

PubMed Central

Yang, Wenwen; Tang, Hongzhi; Ni, Jun; Wu, Qiulin; Hua, Dongliang; Tao, Fei; Xu, Ping

2013-01-01

Production of flavors from natural substrates by microbial transformation has become a growing and expanding field of study over the past decades. Vanillin, a major component of vanilla flavor, is a principal flavoring compound used worldwide. Streptomyces sp. strain V-1 is known to be one of the most promising microbial producers of natural vanillin from ferulic acid. Although identification of the microbial genes involved in the biotransformation of ferulic acid to vanillin has been previously reported, purification and detailed characterization of the corresponding enzymes with important functions have rarely been studied. In this study, we isolated and identified 2 critical genes, fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, which are involved in the vanillin production from ferulic acid. Both genes were heterologously expressed in Escherichia coli, and the resting cell reactions for converting ferulic acid to vanillin were performed. The corresponding crucial enzymes, Fcs and Ech, were purified for the first time and the enzymatic activity of each purified protein was studied. Furthermore, Fcs was comprehensively characterized, at an optimal pH of 7.0 and temperature of 30°C. Kinetic constants for Fcs revealed the apparent K m, k cat, and V max values to be 0.35 mM, 67.7 s−1, and 78.2 U mg−1, respectively. The catalytic efficiency (k cat/K m) value of Fcs was 193.4 mM−1 s−1 for ferulic acid. The characterization of Fcs and Ech may be helpful for further research in the field of enzymatic engineering and metabolic regulation. PMID:23840666

[Risk for hyperkalemia during long-term treatment with angiotensin-converting enzyme inhibitors in insulin-dependent type 2 diabetics in relation to the glomerular filtration rate].

PubMed

Raml, A; Schmekal, B; Grafinger, P; Biesenbach, G

2001-11-23

The risk for hyperkalaemia during therapy with angiotensin-converting enzyme inhibitors is especially increased in the elderly diabetic because of a decrease in glomerular filtration rate (GFR), as well as the occurrence of hyporeninaemic hypoaldosteronism. We evaluated the risk for hyperkalaemia under long-term angiotensin-converting enyzme inhibition in 86 insulin-dependent type 2 diabetic patients in relation to their GFR. We compared the influence of a 3 to 6 months long treatment with angiotensin-converting enzyme inhibitors on the serum potassium levels, the creatinine clearance and the urinary albumin excretion in insulin-dependent type 2 diabetic patients with an initial creatinine clearance < 50 ml/min/1.73m(2) (n = 15, age 66 +/- 6 years) and >/= 50 ml/min/1.73m(2) respectively (n = 71, age 61 +/- 10 years). In addition, we also investigated the influence on the metabolic control and the blood pressure values in both groups of patients. In the patients with creatinine clearance >/= 50 ml/min/1,73m(2) the mean potassium level increased from 4.3 +/- 0.2 to 4.6 +/- 0.4 mmol/l (P < 0,01), while the incidence of a potassium level > 5 mmol/l was 17 %. In the group with a creatinine clearance < 50 ml/min/1.73m(2) the potassium level rose from 4.5 +/- 0.2 to 5.0 +/- 0.4 mmol/l (P < 0.01). The incidence of potassium levels > 5 mmol/l was 66 % (P < 0,01). In both patient groups the creatinine clearances did not change significantly during angiotensin-converting enzyme inhibition, and the urinary albumin excretion as well as the HbA(1c) values and blood pressure showed only a tendency towards a decrease. Long-term treatment with angiotensin-converting enzyme inhibitors in insulin-dependent type 2 diabetic patients leads to a significant increase in serum potassium. The incidence of hyperkalaemia with potassium levels > 5 mmol/l is significantly higher in the patients with initial creatinine clearance < 50 ml/min/1.73m(2). Severe hyperkalaemia with potassium levels

Real-time investigation of human topoisomerase I reaction kinetics using an optical sensor: a fast method for drug screening and determination of active enzyme concentrations

NASA Astrophysics Data System (ADS)

Kristoffersen, Emil L.; Jørgensen, Line A.; Franch, Oskar; Etzerodt, Michael; Frøhlich, Rikke; Bjergbæk, Lotte; Stougaard, Magnus; Ho, Yi-Ping; Knudsen, Birgitta R.

2015-05-01

Human DNA topoisomerase I (hTopI) is a nuclear enzyme that catalyzes relaxation of super helical tension that arises in the genome during essential DNA metabolic processes. This is accomplished through a common reaction mechanism shared among the type IB topoisomerase enzymes, including eukaryotic and poxvirus topoisomerase I. The mechanism of hTopI is specifically targeted in cancer treatment using camptothecin derivatives. These drugs convert the hTopI activity into a cellular poison, and hence the cytotoxic effects of camptothecin derivatives correlate with the hTopI activity. Therefore, fast and reliable techniques for high throughput measurements of hTopI activity are of high clinical interest. Here we demonstrate potential applications of a fluorophore-quencher based DNA sensor designed for measurement of hTopI cleavage-ligation activities, which are the catalytic steps affected by camptothecin. The kinetic analysis of the hTopI reaction with the DNA sensor exhibits a characteristic burst profile. This is the result of a two-step ping-pong reaction mechanism, where a fast first reaction, the one creating the signal, is followed by a slower second reaction necessary for completion of the catalytic cycle. Hence, the burst profile holds information about two reactions in the enzymatic mechanism. Moreover, it allows the amount of active enzyme in the reaction to be determined. The presented results pave the way for future high throughput drug screening and the potential of measuring active hTopI concentrations in clinical samples for individualized treatment.Human DNA topoisomerase I (hTopI) is a nuclear enzyme that catalyzes relaxation of super helical tension that arises in the genome during essential DNA metabolic processes. This is accomplished through a common reaction mechanism shared among the type IB topoisomerase enzymes, including eukaryotic and poxvirus topoisomerase I. The mechanism of hTopI is specifically targeted in cancer treatment using

Epitope mapping of the domains of human angiotensin converting enzyme.

PubMed

Kugaevskaya, Elena V; Kolesanova, Ekaterina F; Kozin, Sergey A; Veselovsky, Alexander V; Dedinsky, Ilya R; Elisseeva, Yulia E

2006-06-01

Somatic angiotensin converting enzyme (sACE), contains in its single chain two homologous domains (called N- and C-domains), each bearing a functional zinc-dependent active site. The present study aims to define the differences between two sACE domains and to localize experimentally revealed antigenic determinants (B-epitopes) in the recently determined three-dimensional structure of testicular tACE. The predicted linear antigenic determinants of human sACE were determined by peptide scanning ("PEPSCAN") approach. Essential difference was demonstrated between locations of the epitopes in the N- and C-domains. Comparison of arrangement of epitopes in the human domains with the corresponding sequences of some mammalian sACEs enabled to classify the revealed antigenic determinants as variable or conserved areas. The location of antigenic determinants with respect to various structural elements and to functionally important sites of the human sACE C-domain was estimated. The majority of antigenic sites of the C-domain were located at the irregular elements and at the boundaries of secondary structure elements. The data show structural differences between the sACE domains. The experimentally revealed antigenic determinants were in agreement with the recently determined crystal tACE structure. New potential applications are open to successfully produce mono-specific and group-specific antipeptide antibodies.

Angiotensin-Converting Enzyme Inhibition as an Adjunct to Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease

PubMed Central

Curtis, Katrina J.; Meyrick, Victoria M.; Mehta, Bhavin; Haji, Gulam S.; Li, Kawah; Montgomery, Hugh; Man, William D.-C.; Polkey, Michael I.

2016-01-01

Rationale: Epidemiological studies in older individuals have found an association between the use of angiotensin-converting enzyme (ACE) inhibition (ACE-I) therapy and preserved locomotor muscle mass, strength, and walking speed. ACE-I therapy might therefore have a role in the context of pulmonary rehabilitation (PR). Objectives: To investigate the hypothesis that enalapril, an ACE inhibitor, would augment the improvement in exercise capacity seen during PR. Methods: We performed a double-blind, placebo-controlled, parallel-group randomized controlled trial. Patients with chronic obstructive pulmonary disease, who had at least moderate airflow obstruction and were taking part in PR, were randomized to either 10 weeks of therapy with an ACE inhibitor (10 mg enalapril) or placebo. Measurements and Main Results: The primary outcome measurement was the change in peak power (assessed using cycle ergometry) from baseline. Eighty patients were enrolled, 78 were randomized (age 67 ± 8 years; FEV1 48 ± 21% predicted), and 65 completed the trial (34 on placebo, 31 on the ACE inhibitor). The ACE inhibitor–treated group demonstrated a significant reduction in systolic blood pressure (Δ, −16 mm Hg; 95% confidence interval [CI], −22 to −11) and serum ACE activity (Δ, −18 IU/L; 95% CI, −23 to −12) versus placebo (between-group differences, P < 0.0001). Peak power increased significantly more in the placebo group (placebo Δ, +9 W; 95% CI, 5 to 13 vs. ACE-I Δ, +1 W; 95% CI, −2 to 4; between-group difference, 8 W; 95% CI, 3 to 13; P = 0.001). There was no significant between-group difference in quadriceps strength or health-related quality of life. Conclusions: Use of the ACE inhibitor enalapril, together with a program of PR, in patients without an established indication for ACE-I, reduced the peak work rate response to exercise training in patients with chronic obstructive pulmonary disease. PMID:27248440

Angiotensin-Converting Enzyme ID Polymorphism in Patients with Heart Failure Secondary to Chagas Disease

PubMed Central

da Silva, Silene Jacinto; Rassi, Salvador; Pereira, Alexandre da Costa

2017-01-01

Background Changes in the angiotensin-converting enzyme (ACE) gene may contribute to the increase in blood pressure and consequently to the onset of heart failure (HF). The role of polymorphism is very controversial, and its identification in patients with HF secondary to Chagas disease in the Brazilian population is required. Objective To determine ACE polymorphism in patients with HF secondary to Chagas disease and patients with Chagas disease without systolic dysfunction, and to evaluate the relationship of the ACE polymorphism with different clinical variables. Methods This was a comparative clinical study with 193 participants, 103 of them with HF secondary to Chagas disease and 90 with Chagas disease without systolic dysfunction. All patients attended the outpatient department of the General Hospital of the Federal University of Goias general hospital. Alleles I and D of ACE polymorphism were identified by polymerase chain reaction of the respective intron 16 fragments in the ACE gene and visualized by electrophoresis. Results In the group of HF patients, 63% were male, whereas 53.6% of patients with Chagas disease without systolic dysfunction were female (p = 0,001). The time from diagnosis varied from 1 to 50 years. Distribution of DD, ID and II genotypes was similar between the two groups, without statistical significance (p = 0,692). There was no difference in clinical characteristics or I/D genotypes between the groups. Age was significantly different between the groups (p = 0,001), and mean age of patients with HF was 62.5 years. Conclusion No differences were observed in the distribution of (Insertion/Deletion) genotype frequencies of ACE polymorphism between the studied groups. The use of this genetic biomarker was not useful in detecting a possible relationship between ACE polymorphism and clinical manifestations in HF secondary to Chagas disease. PMID:28977050

Angiotensin-Converting Enzyme ID Polymorphism in Patients with Heart Failure Secondary to Chagas Disease.

PubMed

Silva, Silene Jacinto da; Rassi, Salvador; Pereira, Alexandre da Costa

2017-10-01

Changes in the angiotensin-converting enzyme (ACE) gene may contribute to the increase in blood pressure and consequently to the onset of heart failure (HF). The role of polymorphism is very controversial, and its identification in patients with HF secondary to Chagas disease in the Brazilian population is required. To determine ACE polymorphism in patients with HF secondary to Chagas disease and patients with Chagas disease without systolic dysfunction, and to evaluate the relationship of the ACE polymorphism with different clinical variables. This was a comparative clinical study with 193 participants, 103 of them with HF secondary to Chagas disease and 90 with Chagas disease without systolic dysfunction. All patients attended the outpatient department of the General Hospital of the Federal University of Goias general hospital. Alleles I and D of ACE polymorphism were identified by polymerase chain reaction of the respective intron 16 fragments in the ACE gene and visualized by electrophoresis. In the group of HF patients, 63% were male, whereas 53.6% of patients with Chagas disease without systolic dysfunction were female (p = 0,001). The time from diagnosis varied from 1 to 50 years. Distribution of DD, ID and II genotypes was similar between the two groups, without statistical significance (p = 0,692). There was no difference in clinical characteristics or I/D genotypes between the groups. Age was significantly different between the groups (p = 0,001), and mean age of patients with HF was 62.5 years. No differences were observed in the distribution of (Insertion/Deletion) genotype frequencies of ACE polymorphism between the studied groups. The use of this genetic biomarker was not useful in detecting a possible relationship between ACE polymorphism and clinical manifestations in HF secondary to Chagas disease.

Expanding the phenotypic and mutational spectrum in microcephalic osteodysplastic primordial dwarfism type I.

PubMed

Abdel-Salam, Ghada M H; Abdel-Hamid, Mohamed S; Issa, Mahmoud; Magdy, Ahmed; El-Kotoury, Ahmed; Amr, Khalda

2012-06-01

Mutations in the RNU4ATAC gene cause microcephalic osteodysplastic primordial dwarfism type I. It encodes U4atac, a small nuclear RNA that is a component of the minor spliceosome. Six distinct mutations in 30 patients diagnosed as microcephalic osteodysplastic primordial dwarfism type I have been described. We report on three additional patients from two unrelated families presenting with a milder phenotype of microcephalic osteodysplastic primordial dwarfism type I and metopic synostosis. Patient 1 had two novel heterozygous mutations in the 3' prime stem-loop, g.66G > C and g.124G > A while Patients 2 and 3 had a homozygous mutation g.55G > A in the 5' prime stem-loop. Although they manifested the known spectrum of clinical features of microcephalic osteodysplastic primordial dwarfism type I, they lacked evidence of severe developmental delay and neurological symptoms. These findings expand the mutational and phenotypic spectrum of this syndrome. Copyright © 2012 Wiley Periodicals, Inc.

Identification and characterisation of the angiotensin converting enzyme-3 (ACE3) gene: a novel mammalian homologue of ACE

PubMed Central

Rella, Monika; Elliot, Joann L; Revett, Timothy J; Lanfear, Jerry; Phelan, Anne; Jackson, Richard M; Turner, Anthony J; Hooper, Nigel M

2007-01-01

Background Mammalian angiotensin converting enzyme (ACE) plays a key role in blood pressure regulation. Although multiple ACE-like proteins exist in non-mammalian organisms, to date only one other ACE homologue, ACE2, has been identified in mammals. Results Here we report the identification and characterisation of the gene encoding a third homologue of ACE, termed ACE3, in several mammalian genomes. The ACE3 gene is located on the same chromosome downstream of the ACE gene. Multiple sequence alignment and molecular modelling have been employed to characterise the predicted ACE3 protein. In mouse, rat, cow and dog, the predicted protein has mutations in some of the critical residues involved in catalysis, including the catalytic Glu in the HEXXH zinc binding motif which is Gln, and ESTs or reverse-transcription PCR indicate that the gene is expressed. In humans, the predicted ACE3 protein has an intact HEXXH motif, but there are other deletions and insertions in the gene and no ESTs have been identified. Conclusion In the genomes of several mammalian species there is a gene that encodes a novel, single domain ACE-like protein, ACE3. In mouse, rat, cow and dog ACE3, the catalytic Glu is replaced by Gln in the putative zinc binding motif, indicating that in these species ACE3 would lack catalytic activity as a zinc metalloprotease. In humans, no evidence was found that the ACE3 gene is expressed and the presence of deletions and insertions in the sequence indicate that ACE3 is a pseudogene. PMID:17597519

Budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme upon high-altitude exposure.

PubMed

Li, Hui-Jie; Zheng, Cheng-Rong; Chen, Guo-Zhu; Qin, Jun; Zhang, Ji-Hang; Yu, Jie; Zhang, En-Hao; Huang, Lan

2016-01-01

Inhaled budesonide is a novel approach to prevent acute mountain sickness (AMS). However, its mechanism is not completely understood. We aimed to investigate the effects of budesonide and dexamethasone on renin-angiotensin-aldosterone system in AMS prevention. Data were obtained from a randomised controlled trial including 138 participants. The participants were randomly assigned to receive budesonide, dexamethasone or placebo as prophylaxis before they travelled to 3450 m altitude from 400 m by car. Their plasma concentrations of renin, angiotensin-converting enzyme (ACE) and aldosterone were measured at both altitudes. All parameters were comparable among the three groups at 400 m. After high-altitude exposure of 3450, renin in all groups increased significantly; the ACE, aldosterone concentrations, as well as the aldosterone/renin ratio, rose markedly in the dexamethasone and placebo groups but not in the budesonide group. Moreover, the aldosterone/renin ratio correlated closely with ACE concentration. Upon acute high-altitude exposure, budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme. © The Author(s) 2016.

Budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme upon high-altitude exposure

PubMed Central

Li, Hui-Jie; Zheng, Cheng-Rong; Chen, Guo-Zhu; Qin, Jun; Zhang, Ji-Hang; Yu, Jie; Zhang, En-Hao; Huang, Lan

2016-01-01

Introduction: Inhaled budesonide is a novel approach to prevent acute mountain sickness (AMS). However, its mechanism is not completely understood. We aimed to investigate the effects of budesonide and dexamethasone on renin–angiotensin–aldosterone system in AMS prevention. Materials and methods: Data were obtained from a randomised controlled trial including 138 participants. The participants were randomly assigned to receive budesonide, dexamethasone or placebo as prophylaxis before they travelled to 3450 m altitude from 400 m by car. Their plasma concentrations of renin, angiotensin-converting enzyme (ACE) and aldosterone were measured at both altitudes. Results: All parameters were comparable among the three groups at 400 m. After high-altitude exposure of 3450, renin in all groups increased significantly; the ACE, aldosterone concentrations, as well as the aldosterone/renin ratio, rose markedly in the dexamethasone and placebo groups but not in the budesonide group. Moreover, the aldosterone/renin ratio correlated closely with ACE concentration. Conclusions: Upon acute high-altitude exposure, budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme. PMID:27317302

Germinal mosaicism of PAX3 mutation caused Waardenburg syndrome type I.

PubMed

Chen, Kaitian; Zhan, Yuan; Wu, Xuan; Zong, Ling; Jiang, Hongyan

2018-01-01

Waardenburg syndrome mutations are most often recurrent or de novo. The rate of familial recurrence is low and families with several affected children are extremely rare. In this study, we aimed to clarify the underlying hereditary cause of Waardenburg syndrome type I in two siblings in a Chinese family, with a mother affected by prelingual mild hearing loss and a father who was negative for clinical symptoms of Waardenburg syndrome and had a normal hearing threshold. Complete characteristic features of the family members were recorded and genetic sequencing and parent-child relationship analyses were performed. The two probands were found to share double mutations in the PAX3/GJB2 genes that caused concurrent hearing loss in Waardenburg syndrome type I. Their mother carried the GJB2 c.109G > A homozygous mutation; however, neither the novel PAX3 c.592delG mutation, nor the Waardenburg syndrome phenotype, was observed in either parent. These previously unreported digenic mutations in PAX3/GJB2 resulted in deafness associated with Waardenburg syndrome type I in this family. To our knowledge, this is the first report describing germinal mosaicism in Waardenburg syndrome. This concept is important because it complicates genetic counseling of this family regarding the risk of recurrence of the mutations in subsequent pregnancies. Copyright © 2017 Elsevier B.V. All rights reserved.

GTF2I mutation frequently occurs in more indolent thymic epithelial tumors and predicts better prognosis.

PubMed

Feng, Yanfen; Lei, Yiyan; Wu, Xiaoyan; Huang, Yuhua; Rao, Huilan; Zhang, Yu; Wang, Fang

2017-08-01

A missense mutation in GTF2I was previously identified in thymic epithelioid tumor (TET). However, the clinicopathological relevance of GTF2I mutation has not been illustrated. We studied the prognostic importance of GTF2I mutation as well as its relation to histological subtypes in a large number of TETs. TET samples from 296 patients with clinical and follow-up data were collected, and histological subtypes were classified. Analysis of the GTF2I (chromosome 7 c.74146970T>A) mutation was undertaken by using quantitative real time polymerase chain reaction (qPCR) and direct sequencing. The association of GTF2I mutation with clinicopathological features as well as prognosis was analyzed. One hundred twenty-four out of 296 (41.9%) patients harbored the GTF2I mutation (chromosome 7 c.74146970T>A). GTF2I mutation was observed in 20 (87.0%) cases of type A thymoma, 70 (78.7%) of type AB thymoma, and the frequency decreased with the degree of histological subtype aggressiveness, with the lowest rate in thymic carcinoma (7.7%). The difference of GTF2I mutation distribution in histological subtypes was statistically significant (p<0.001). The GTF2I mutation was found more frequently in patients with early Masaoka stage (I-II, n=112, 90.3%) than in those with advanced stage (III-IV) disease (n=12, 9.6%, p<0.001). However, only histological subtype significantly predicted the presence of the GTF2I mutation in patients with TETs. The presence of the GTF2I mutation correlated with better prognosis (90.0% compared to 72.0% 5-year survival, and 86% compared to 56% 10-year survival, respectively; log-rank p=0.001). Moreover, it was an independent prognostic factor [hazard ratio (HR), 0.35; 95% confidential interval (CI), 0.15-0.81; p=0.014)]. The frequency of the GTF2I mutation is higher in more indolent TETs, and correlates with better prognosis. Further studies are required to elucidate the role of the GTF2I mutation in TETs and its clinical application. Copyright © 2017

Mutation rates among RNA viruses

PubMed Central

Drake, John W.; Holland, John J.

1999-01-01

The rate of spontaneous mutation is a key parameter in modeling the genetic structure and evolution of populations. The impact of the accumulated load of mutations and the consequences of increasing the mutation rate are important in assessing the genetic health of populations. Mutation frequencies are among the more directly measurable population parameters, although the information needed to convert them into mutation rates is often lacking. A previous analysis of mutation rates in RNA viruses (specifically in riboviruses rather than retroviruses) was constrained by the quality and quantity of available measurements and by the lack of a specific theoretical framework for converting mutation frequencies into mutation rates in this group of organisms. Here, we describe a simple relation between ribovirus mutation frequencies and mutation rates, apply it to the best (albeit far from satisfactory) available data, and observe a central value for the mutation rate per genome per replication of μg ≈ 0.76. (The rate per round of cell infection is twice this value or about 1.5.) This value is so large, and ribovirus genomes are so informationally dense, that even a modest increase extinguishes the population. PMID:10570172

Necessity of angiotensin-converting enzyme-related gene for cardiac functions and longevity of Drosophila melanogaster assessed by optical coherence tomography

NASA Astrophysics Data System (ADS)

Liao, Fang-Tsu; Chang, Cheng-Yi; Su, Ming-Tsan; Kuo, Wen-Chuan

2014-01-01

Prior studies have established the necessity of an angiotensin-converting enzyme-related (ACER) gene for heart morphogenesis of Drosophila. Nevertheless, the physiology of ACER has yet to be comprehensively understood. Herein, we employed RNA interference to down-regulate the expression of ACER in Drosophila's heart and swept source optical coherence tomography to assess whether ACER is required for cardiac functions in living adult flies. Several contractile parameters of Drosophila heart, including the heart rate (HR), end-diastolic diameter (EDD), end-systolic diameter (ESD), percent fractional shortening (%FS), and stress-induced cardiac performance, are shown, which are age dependent. These age-dependent cardiac functions declined significantly when ACER was down-regulated. Moreover, the lifespans of ACER knock-down flies were significantly shorter than those of wild-type control flies. Thus, we posit that ACER, the Drosophila ortholog of mammalian angiotensin-converting enzyme 2 (ACE2), is essential for both heart physiology and longevity of animals. Since mammalian ACE2 controls many cardiovascular physiological features and is implicated in cardiomyopathies, our findings that ACER plays conserved roles in genetically tractable animals will pave the way for uncovering the genetic pathway that controls the renin-angiotensin system.

Pharmacokinetic interaction between cefdinir and two angiotensin-converting enzyme inhibitors in rats.

PubMed Central

Jacolot, A; Tod, M; Petitjean, O

1996-01-01

The pharmacokinetic interaction between cefdinir and an angiotensin-converting enzyme inhibitor (captopril or quinapril) was investigated in rats. The linearity of cefdinir pharmacokinetics was demonstrated in three groups of rats receiving 10, 20, or 40 mg of cefdinir per kg of body weight intravenously. Then, three other groups of rats were established as follows: group 1 (n = 5) received cefdinir (10 mg/kg) intravenously, and 12 blood samples per rat were drawn between 0 and 8 h after injection of the dose; group 2 (n = 5) was treated in the same way as group 1, but captopril (0.8 mg/kg) was coadministered by intraintestinal injection into all animals; group 3 (n = 6) was treated in the same way as group 2, but quinapril (0.8 mg/kg) replaced captopril. Plasma cefdinir concentrations were measured by liquid chromatography, and the data were analyzed by a noncompartmental method. Finally, three groups of four or five rats each were set up as described above, but the cefdinir dose was 20 mg/kg and the animals were sacrificed 1 h after drug injection to collect blood to determine the unbound cefdinir fraction (fu) by ultrafiltration. The angiotensin-converting enzyme inhibitors increased the mean cefdinir area under the concentration-time curve up to 8 h by a factor of 1.8 (captopril; P < 0.05) and a factor of 3.5 (quinapril; P < 0.05). With captopril, mean cefdinir clearance was decreased by a factor of 2, and the volume of distribution increased by the same factor, while the fu increased from 15.4% +/- 3.0% (cefdinir alone) to 22.8% +/- 10.9% (cefdinir plus captopril). Captopril increased the cefdinir half-life from 0.62 +/- 0.17 to 2.92 +/- 0.95 h. With quinapril, the interaction was so strong that no elimination phase was detectable in four of the six rats, and therefore, no pharmacokinetic parameter values other than the cefdinir fu could be calculated; the cefdinir fu increased to 25.1% +/- 11.1%. It is concluded that captopril and quinapril (and/or their

Novel whey-derived peptides with inhibitory effect against angiotensin-converting enzyme: in vitro effect and stability to gastrointestinal enzymes.

PubMed

Tavares, Tânia; Contreras, Maria Del Mar; Amorim, Manuela; Pintado, Manuela; Recio, Isidra; Malcata, F Xavier

2011-05-01

Whey protein concentrate (WPC) was subjected to enzymatic hydrolysis by proteases from the flowers of Cynara cardunculus, and the resulting angiotensin-converting enzyme (ACE)-inhibitory effect was monitored. The whole WPC hydrolysate exhibited an IC(50) value of 52.9 ± 2.9 μg/mL, whereas the associated peptide fraction with molecular weight below 3 kDa scored 23.6 ± 1.1 μg/mL. The latter fraction was submitted to RP-HPLC, and 6 fractions were resolved that exhibited ACE-inhibitory effects. Among the various peptides found, a total of 14 were identified via sequencing with an ion-trap mass spectrometer. Eleven of these peptides were synthesized de novo--to validate their ACE-inhibitory effect, and also to ascertain their stability when exposed to simulated gastrointestinal digestion. Among them, three novel, highly potent peptides were found, corresponding to α-lactalbumin f(16-26)--with the sequence KGYGGVSLPEW, α-lactalbumin f(97-104) with DKVGINYW, and β-lactoglobulin f(33-42) with DAQSAPLRVY; their IC(50) values were as low as 0.80 ± 0.1, 25.2 ± 1.0 and 13.0 ± 1.0 μg/mL, respectively. None of them remained stable in the presence of gastrointestinal enzymes: they were partially, or even totally hydrolyzed to smaller peptides--yet the observed ACE-inhibitory effects were not severely affected for two of those peptides. Copyright © 2011 Elsevier Inc. All rights reserved.

Enzyme Hydrolysates from Stichopus horrens as a New Source for Angiotensin-Converting Enzyme Inhibitory Peptides

PubMed Central

Forghani, Bita; Ebrahimpour, Afshin; Bakar, Jamilah; Abdul Hamid, Azizah; Hassan, Zaiton; Saari, Nazamid

2012-01-01

Stichopus horrens flesh was explored as a potential source for generating peptides with angiotensin-converting enzyme (ACE) inhibitory capacity using 6 proteases, namely alcalase, flavourzyme, trypsin, papain, bromelain, and protamex. Degree of hydrolysis (DH) and peptide profiling (SDS-PAGE) of Stichopus horrens hydrolysates (SHHs) was also assessed. Alcalase hydrolysate showed the highest DH value (39.8%) followed by flavourzyme hydrolysate (32.7%). Overall, alcalase hydrolysate exhibited the highest ACE inhibitory activity (IC50 value of 0.41 mg/mL) followed by flavourzyme hydrolysate (IC50 value of 2.24 mg/mL), trypsin hydrolysate (IC50 value of 2.28 mg/mL), papain hydrolysate (IC50 value of 2.48 mg/mL), bromelain hydrolysate (IC50 value of 4.21 mg/mL), and protamex hydrolysate (IC50 value of 6.38 mg/mL). The SDS-PAGE results showed that alcalase hydrolysate represented a unique pattern compared to others, which yielded potent ACE inhibitory peptides with molecular weight distribution lower than 20 kDa. The evaluation of the relationship between DH and IC50 values of alcalase and flavourzyme hydrolysates revealed that the trend between those parameters was related to the type of the protease used. We concluded that the tested SHHs would be used as a potential source of functional ACE inhibitory peptides for physiological benefits. PMID:22927875

Enzyme Hydrolysates from Stichopus horrens as a New Source for Angiotensin-Converting Enzyme Inhibitory Peptides.

PubMed

Forghani, Bita; Ebrahimpour, Afshin; Bakar, Jamilah; Abdul Hamid, Azizah; Hassan, Zaiton; Saari, Nazamid

2012-01-01

Stichopus horrens flesh was explored as a potential source for generating peptides with angiotensin-converting enzyme (ACE) inhibitory capacity using 6 proteases, namely alcalase, flavourzyme, trypsin, papain, bromelain, and protamex. Degree of hydrolysis (DH) and peptide profiling (SDS-PAGE) of Stichopus horrens hydrolysates (SHHs) was also assessed. Alcalase hydrolysate showed the highest DH value (39.8%) followed by flavourzyme hydrolysate (32.7%). Overall, alcalase hydrolysate exhibited the highest ACE inhibitory activity (IC(50) value of 0.41 mg/mL) followed by flavourzyme hydrolysate (IC(50) value of 2.24 mg/mL), trypsin hydrolysate (IC(50) value of 2.28 mg/mL), papain hydrolysate (IC(50) value of 2.48 mg/mL), bromelain hydrolysate (IC(50) value of 4.21 mg/mL), and protamex hydrolysate (IC(50) value of 6.38 mg/mL). The SDS-PAGE results showed that alcalase hydrolysate represented a unique pattern compared to others, which yielded potent ACE inhibitory peptides with molecular weight distribution lower than 20 kDa. The evaluation of the relationship between DH and IC(50) values of alcalase and flavourzyme hydrolysates revealed that the trend between those parameters was related to the type of the protease used. We concluded that the tested SHHs would be used as a potential source of functional ACE inhibitory peptides for physiological benefits.

High frequency of DD polymorphism of the angiotensin-converting enzyme gene in Turkish asthmatic patients.

PubMed

Urhan, Meral; Degirmenci, Irfan; Harmanci, Emel; Gunes, Hasan V; Metintas, Muzaffer; Basaran, Ayse

2004-01-01

The aim of this study is to detect the incidence of the angiotensin-converting enzyme (ACE) gene polymorphism in Turkish asthmatic patients and to examine whether there is an association between the disease and ACE gene polymorphism. In our study, the genomic DNA of 100 asthmatic patients and 88 healthy subjects was analyzed Genomic DNA was isolated from peripheral blood by using standard methods. The intron 16 of the ACE gene was amplified by the polymerase chain reaction (PCR) method using primers ACE and ACEX to examine the presence and absence of a 287-base pair (bp) DNA fragment that showed I/D polymorphism genotypes. PCR products were separated by agarose gel electrophoresis and were visualized by a charge-coupled device camera. Serum ACE activities were measured using an ACE kit. The results were evaluated statistically using the chi-square test and one-way analysis of variance. Although the population of patients with asthma was characterized by a higher frequency (30%) of the DD genotype of ACE, they were characterized by lower frequency (48%) of the ID genotype of ACE (DD, 16%, and ID, 64%, in healthy control subjects). The frequency of the I and D alleles of the ACE gene was not significantly different between asthmatic patients (0.46/0.54) and healthy controls (0.52/ 0.48). In addition, in both asthmatic patients and controls, there was a significant decrease of the levels of ACE activity in individuals that have II genotypes when compared with individuals that have DD genotypes. ACE activities were increased significantly in all asthmatic patients (67.20 +/- 1.95 IU/L) compared with all healthy controls (60.90 +/- 2.12 IU/L).

N-linked glycosylation of recombinant cellobiohydrolase I (Cel7A) from Penicillium verruculosum and its effect on the enzyme activity.

PubMed

Dotsenko, Anna S; Gusakov, Alexander V; Volkov, Pavel V; Rozhkova, Aleksandra M; Sinitsyn, Arkady P

2016-02-01

Cellobiohydrolase I from Penicillium verruculosum (PvCel7A) has four potential N-glycosylation sites at its catalytic module: Asn45, Asn194, Asn388, and Asn430. In order to investigate how the N-glycosylation influences the activity and other properties of the enzyme, the wild type (wt) PvCel7A and its mutant forms, carrying Asn to Ala substitutions, were cloned into Penicillium canescens PCA10 (niaD-) strain, a fungal host for production of heterologous proteins. The rPvCel7A-wt and N45A, N194A, N388A mutants were successfully expressed and purified for characterization, whereas the expression of N430A mutant was not achieved. The MALDI-TOF mass spectrometry fingerprinting of peptides, obtained as a result of digestion of rPvCel7A forms with specific proteases, showed that the N-linked glycans represent variable high-mannose oligosaccharides and the products of their sequential enzymatic trimming, according to the formula (Man)0-13 (GlcNAc)2 , or a single GlcNAc residue. Mutations had no notable effect on pH-optimum of PvCel7A activity and enzyme thermostability. However, the mutations influenced both the enzyme adsorption ability on Avicel and its activity against natural and synthetic substrates. In particular, the N45A mutation led to a significant increase in the rate of Avicel and milled aspen wood hydrolysis, while the substrate digestion rates in the case of N194A and N388A mutants were notably lower relative to rPvCel7A-wt. These data, together with data of 3D structural modeling of the PvCel7A catalytic module, indicate that the N-linked glycans are an important part of the processive catalytic machinery of PvCel7A. © 2015 Wiley Periodicals, Inc.

Activation of angiotensin-converting enzyme 2 (ACE2) attenuates allergic airway inflammation in rat asthma model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhawale, Vaibhav Shrirang; Amara, Venkateswara Rao

Angiotensin-I converting enzyme (ACE) is positively correlated to asthma, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS) and is highly expressed in lungs. ACE2, the counteracting enzyme of ACE, was proven to be protective in pulmonary, cardiovascular diseases. In the present study we checked the effect of ACE2 activation in animal model of asthma. Asthma was induced in male wistar rats by sensitization and challenge with ovalbumin and then treated with ACE2 activator, diminazene aceturate (DIZE) for 2 weeks. 48 h after last allergen challenge, animals were anesthetized, blood, BALF, femoral bone marrow lavage were collected for leucocytemore » count; trachea for measuring airway responsiveness to carbachol; lungs and heart were isolated for histological studies and western blotting. In our animal model, the characteristic features of asthma such as altered airway responsiveness to carbachol, eosinophilia and neutrophilia were observed. Western blotting revealed the increased pulmonary expression of ACE1, IL-1β, IL-4, NF-κB, BCL2, p-AKT, p-p38 and decreased expression of ACE2 and IκB. DIZE treatment prevented these alterations. Intraalveolar interstitial thickening, inflammatory cell infiltration, interstitial fibrosis, oxidative stress and right ventricular hypertrophy in asthma control animals were also reversed by DIZE treatment. Activation of ACE2 by DIZE conferred protection against asthma as evident from biochemical, functional, histological and molecular parameters. To the best of our knowledge, we report for the first time that activation of ACE2 by DIZE prevents asthma progression by altering AKT, p38, NF-κB and other inflammatory markers. - Highlights: • Diminazene aceturate (DIZE), an ACE2 activator prevents ovalbumin-induced asthma. • DIZE acted by upregulating ACE2, downregulating ACE1, MAPKs, markers of inflammation, apoptosis. • DIZE reduced airway inflammation, fibrosis, right ventricular

Hydrolysis of substance p and neurotensin by converting enzyme and neutral endopeptidase.

PubMed

Skidgel, R A; Engelbrecht, S; Johnson, A R; Erdös, E G

1984-01-01

Angiotensin I converting enzyme (ACE) and neutral endopeptidase ("enkephalinase"; NEP), were purified to homogeneity from human kidney. NEP cleaved substance P (SP) at Gln6-Phe7,-Phe8, and Gly9-Leu10 and neurotensin (NT) at Pro10-Tyr11 and Tyr11-Ile12. NEP hydrolyzed 0.1 mM SP, NT and their C-terminal fragments at the following rates (mumol/min/mg): SP1-11 = 7.8, SP4-11 = 11.7, SP5-11 = 15.4, SP6-11 = 15.6, SP8-11 = 6.7, NT1-13 = 2.9, and NT8-13 = 4.0. Purified ACE rapidly inactivated SP as measured in bioassay. HPLC analysis showed that ACE cleaved SP at Phe8-Gly9 and Gly9-Leu10 to release C-terminal tri- and dipeptide (ratio = 4:1). The hydrolysis was Cl- dependent and inhibited by captopril. ACE released mainly C-terminal tripeptide from SP methyl ester, but only dipeptide from SP free acid. Modification of arginine residues in ACE with cyclohexanedione or butanedione similarly inhibited hydrolysis of SP, bradykinin and Bz-Gly-Phe-Arg (80-93%) indicating an active site arginine is required for hydrolysis of SP. ACE hydrolyzed NT at Tyr11-Ile12 to release Ile12-Leu13. SP, NT and their derivatives (0.1 mM) were cleaved by ACE at the following rates (mumol/min/mg): SP1-11 = 1.2, SP methyl ester = 0.7, SP free acid = 8.5, SP4-11 = 2.4, SP5-11 = 0.9, SP6-11 = 1.4, SP8-11 = 0, NT1-13 = 0.2, and NT8-13 = 1.3. Peptide substrates were used as inhibitors of ACE (substrate = FA-Phe-Gly-Gly) and NEP (substrate = Leu5-enkephalin).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin converting enzyme (ACE) gene expression in experimentally induced liver cirrhosis in rats.

PubMed

Shahid, Syed Muhammad; Fatima, Syeda Nuzhat; Mahboob, Tabassum

2013-09-01

Angiotensin converting enzyme (ACE) is a key player of Renin Angiotensin System (RAS), involved in conversion of active product, angiotensin-II. Alterations in RAS have been implicated in the pathophysiology of various diseases involving heart, kidney, lung and liver. This study is designed to investigate the association of ACE gene expression in induction of liver cirrhosis in rats. Total 12 male albino Wistar rats were selected and divided in two groups. Control group received 0.9% NaCl, where as Test group received thioacidamide (TAA), dissolved in 0.9%NaCl, injected intraperitoneally at a dosage of 200mg/Kg of body weight, twice a week for 12 weeks. The rats were decapitated and blood sample was collected at the end of experimental period and used for liver functions, enzyme activity, antioxidant enzymes and lipid peroxidation estimations. Genomic DNA was isolated from excised tissue determine the ACE genotypes using specific primers. The ACE gene expression in liver tissue was assessed using the quantitative RT-PCR method. The activity of ALT, total and direct bilirubin, SOD and CAT levels were significantly high (p<0.05) and level of MDA was significantly low (p<0.05) in TAA treated rats as compared to control rats. The ACE gene expression after 12 weeks TAA treatment in cirrhotic rats was significantly increased (p<0.05) in comparison to controls. This study describes the importance of RAS in the development of hepatic fibrosis and the benefits of modulation of this system ACE gene expression. The finding of major up-regulation of ACE in the experimental rat liver provides further insight into the complexities of the RAS and its regulation in liver injury. The development of specific modulators of ACE activity and function, in future, will help determine the role of ACE and its genetic variants in the pathophysiology of liver disease.

Angiotensin-converting enzyme gene polymorphism in arrhythmogenic right ventricular dysplasia: is DD genotype helpful in predicting syncope risk?

PubMed

Ozben, Beste; Altun, Ibrahim; Sabri Hancer, Veysel; Bilge, Ahmet Kaya; Tanrikulu, Azra Meryem; Diz-Kucukkaya, Reyhan; Fak, Ali Serdar; Yilmaz, Ercument; Adalet, Kamil

2008-12-01

Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable disorder characterised by fibrofatty replacement of right ventricular myocytes and increased risk of ventricular arrhythmias and sudden cardiac death. Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism affects myocardial ACE levels. DD genotype favours myocardial fibrosis and is associated with malignant ventricular tachycardia. The aim of this study was to explore ACE gene polymorphism in ARVD patients. Twenty-nine patients with ARVD and 24 controls were included. All ARVD patients had documented sustained ventricular tachycardia. Thirteen patients had syncopal episodes. Six patients were resuscitated from sudden cardiac death. ACE gene polymorphism was identified by polymerase chain reaction technique. There was no significant difference in DD genotype frequency between ARVD patients and controls (44.8% vs. 45.8%, p=0.94). However, DD genotype frequency was significantly higher in ARVD patients with syncopal episodes compared to those without syncope (69.2% vs. 25.0%, p=0.017, odds ratio:6.750, 95% confidence interval: 1.318-34.565). DD genotype was detected in higher frequency also in patients with a family history of sudden cardiac death (66.7% vs. 39.1%,p=0.36). High prevalence of DD genotype in ARVD patients with syncope suggests that ACE I/D polymorphism might be useful in identifying high-risk patients for syncope.

The Relay/Converter Interface Influences Hydrolysis of ATP by Skeletal Muscle Myosin II*

PubMed Central

Bloemink, Marieke J.; Melkani, Girish C.; Bernstein, Sanford I.; Geeves, Michael A.

2016-01-01

The interface between relay and converter domain of muscle myosin is critical for optimal myosin performance. Using Drosophila melanogaster indirect flight muscle S1, we performed a kinetic analysis of the effect of mutations in the converter and relay domain. Introduction of a mutation (R759E) in the converter domain inhibits the steady-state ATPase of myosin S1, whereas an additional mutation in the relay domain (N509K) is able to restore the ATPase toward wild-type values. The R759E S1 construct showed little effect on most steps of the actomyosin ATPase cycle. The exception was a 25–30% reduction in the rate constant of the hydrolysis step, the step coupled to the cross-bridge recovery stroke that involves a change in conformation at the relay/converter domain interface. Significantly, the double mutant restored the hydrolysis step to values similar to the wild-type myosin. Modeling the relay/converter interface suggests a possible interaction between converter residue 759 and relay residue 509 in the actin-detached conformation, which is lost in R759E but is restored in N509K/R759E. This detailed kinetic analysis of Drosophila myosin carrying the R759E mutation shows that the interface between the relay loop and converter domain is important for fine-tuning myosin kinetics, in particular ATP binding and hydrolysis. PMID:26586917

A null mutation in the first enzyme of flavonoid biosynthesis does not affect male fertility in Arabidopsis.

PubMed Central

Burbulis, I E; Iacobucci, M; Shirley, B W

1996-01-01

Flavonoids are a major class of secondary metabolites that serves a multitude of functions in higher plants, including a recently discovered role in male fertility. Surprisingly, Arabidopsis plants deficient in flavonoid biosynthesis appear to be fully fertile. Using RNA gel blot analysis and polymerase chain reaction-based assays, we have shown that a mutation at the 3' splice acceptor site in the Arabidopsis chalcone synthase gene completely disrupts synthesis of the active form of the enzyme. We also confirmed that this enzyme, which catalyzes the first step of flavonoid biosynthesis, is encoded by a single-copy gene. HPLC analysis of whole flowers and stamens was used to show that plants homozygous for the splice site mutation are completely devoid of flavonoids. This work provides compelling evidence that despite the high levels of these compounds in the pollen of most plant species, flavonoids are not universally required for fertility. The role of flavonoids in plant reproduction may therefore offer an example of convergent functional evolution in secondary metabolism. PMID:8672888

[The effect of esmolol on corrected-QT interval, corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients taking an angiotensin-converting enzyme inhibitor].

PubMed

Ceker, Zahit; Takmaz, Suna Akın; Baltaci, Bülent; Başar, Hülya

2015-01-01

The importance of minimizing the exaggerated sympatho-adrenergic responses and QT interval and QT interval dispersion changes that may develop due to laryngoscopy and tracheal intubation during anesthesia induction in the hypertensive patients is clear. Esmolol decreases the hemodynamic response to laryngoscopy and intubation. However, the effect of esmolol in decreasing the prolonged QT interval and QT interval dispersion as induced by laryngoscopy and intubation is controversial. We investigated the effect of esmolol on the hemodynamic, and corrected-QT interval and corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients using angiotensin converting enzyme inhibitors. 60 ASA I-II patients, with essential hypertension using angiotensin converting enzyme inhibitors were included in the study. The esmolol group received esmolol at a bolus dose of 500mcg/kg followed by a 100mcg/kg/min infusion which continued until the 4th min after intubation. The control group received 0.9% saline similar to the esmolol group. The mean blood pressure, heart rate values and the electrocardiogram records were obtained as baseline values before the anesthesia, 5min after esmolol and saline administration, 3min after the induction and 30s, 2min and 4min after intubation. The corrected-QT interval was shorter in the esmolol group (p=0.012), the corrected-QT interval dispersion interval was longer in the control group (p=0.034) and the mean heart rate was higher in the control group (p=0.022) 30s after intubation. The risk of arrhythmia frequency was higher in the control group in the 4-min period following intubation (p=0.038). Endotracheal intubation was found to prolong corrected-QT interval and corrected-QT interval dispersion, and increase the heart rate during anesthesia induction with propofol in hypertensive patients using angiotensin converting enzyme inhibitors. These effects were prevented with esmolol (500mcg/kg bolus, followed by

ANGIOTENSIN-CONVERTING ENZYME 2 ACTIVATION IMPROVES ENDOTHELIAL FUNCTION

PubMed Central

Fraga-Silva, Rodrigo A.; Costa-Fraga, Fabiana P.; Murça, Tatiane M.; Moraes, Patrícia L.; Lima, Augusto Martins; Lautner, Roberto Q.; Castro, Carlos H.; Soares, Célia Maria A.; Borges, Clayton L.; Nadu, Ana Paula; Oliveira, Marilene L.; Shenoy, Vinayak; Katovich, Michael J.; Santos, Robson A.S.; Raizada, Mohan K.; Ferreira, Anderson J.

2013-01-01

Diminished release and function of endothelium-derived nitric oxide (NO) coupled with increases in reactive oxygen species (ROS) production is critical in endothelial dysfunction. Recent evidences have shown that activation of the protective axis of the renin-angiotensin system composed by angiotensin-converting enzyme2 (ACE2), Angiotensin-(1-7) [Ang-(1-7)] and Mas receptor promotes many beneficial vascular effects. This has led us to postulate that activation of intrinsic ACE2 would improve endothelial function by decreasing the ROS production. In the present study, we tested 1-[[2-(dimetilamino)etil]amino]-4-(hidroximetil)-7-[[(4-metilfenil)sulfonil]oxi]-9H-xantona-9 (XNT), a small molecule ACE2 activator, on endothelial function to validate this hypothesis. In vivo treatment with XNT (1mg/kg/day for 4 weeks) improved the endothelial function of spontaneously hypertensive rats and of streptozotocin-induced diabetic rats when evaluated through the vasorelaxant responses to acetylcholine/sodium nitroprusside. Acute in vitro incubation with XNT caused endothelial-dependent vasorelaxation in aortic rings of rats. This vasorelaxation effect was attenuated by the Mas antagonist D-pro7-Ang-(1-7) and it was reduced in Mas knockout mice. These effects were associated with reduction in ROS production. In addition, Ang II-induced ROS production in human aortic endothelial cells was attenuated by pre-incubation with XNT. These results showed that chronic XNT administration improves the endothelial function of hypertensive and diabetic rat vessels by attenuation of the oxidative stress. Moreover, XNT elicits an endothelial-dependent vasorelaxation response, which was mediated by Mas. Thus, this study indicated that ACE2 activation promotes beneficial effects on the endothelial function and it is a potential target for treating cardiovascular disease. PMID:23608648

Four new type I restriction enzymes identified in Escherichia coli clinical isolates

PubMed Central

Kasarjian, Julie K. A.; Kodama, Yoshiaki; Iida, Masatake; Matsuda, Katsura; Ryu, Junichi

2005-01-01

Using a plasmid transformation method and the RM search computer program, four type I restriction enzymes with new recognition sites and two isoschizomers (EcoBI and Eco377I) were identified in a collection of clinical Escherichia coli isolates. These new enzymes were designated Eco394I, Eco826I, Eco851I and Eco912I. Their recognition sequences were determined to be GAC(5N)RTAAY, GCA(6N)CTGA, GTCA(6N)TGAY and CAC(5N)TGGC, respectively. A methylation sensitivity assay, using various synthetic oligonucleotides, was used to identify the adenines that prevent cleavage when methylated (underlined). These results suggest that type I enzymes are abundant in E.coli and many other bacteria, as has been inferred from bacterial genome sequencing projects. PMID:16040596

Association of Angiotensin-Converting Enzyme (ACE) Gene Polymorphism with Inflammation and Cellular Cytotoxicity in Vitiligo Patients.

PubMed

Rashed, Laila; Abdel Hay, Rania; Mahmoud, Rania; Hasan, Nermeen; Zahra, Amr; Fayez, Salwa

2015-01-01

Vitiligo is a disorder with profound heterogeneity in its aetio-pathophysiology. Angiotensin converting enzyme (ACE) plays an important role in the physiology of the vasculature, blood pressure and inflammation. An insertion/deletion (I/D) polymorphism of the ACE gene was reported be associated with the development of vitiligo. Our aim was to evaluate the ACE I/D polymorphism in vitiligo patients and controls. Our second aim was to find a possible association between ACE gene polymorphism and inflammatory mediators (as interleukin (IL)-6) and/or cellular cytotoxicity induced by serum nitrite (as a breakdown product of the cytotoxic nitric oxide) in vitiligo patients. This case-control study included 74 vitiligo patients and 75 apparently healthy controls. The distribution of ACE gene I/D genotype was investigated using PCR. Serum ACE, IL-6 and nitrite were measured by colorimetric method, ELISA and Griess assay respectively. The ACE allele frequency was significantly different between vitiligo patients and healthy controls (P = 0.026). However there was no significant difference between the ACE genotyping frequency in both groups (P = 0.115). There were statistically significant higher VIDA score (P = 0.007), and serum IL-6 (P < 0.001) in patients with the DD genotype when compared to other genotypes. Serum nitrite in patients with the DD genotype was significantly higher (P = 0.007) when compared to patients with II genotype. Serum levels of ACE, IL-6 and nitrite in vitiligo patients were statistically significantly higher than those in controls. As a conclusion, ACE gene polymorphism might grant susceptibility to develop vitiligo. Serum IL-6 and nitrite levels might have an important role in the pathogenesis of vitiligo. Targeting these two factors might have an implication in the treatment of some resistant cases.

N- vs. C-Domain Selectivity of Catalytic Inactivation of Human Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

PubMed Central

Hocharoen, Lalintip; Joyner, Jeff C.; Cowan, J. A.

2014-01-01

The N- and C-terminal domains of human somatic Angiotensin I Converting Enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates were tested for both reversible binding and irreversible catalytic inactivation of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of the M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and orientation factors (double-filter effect). PMID:24228790

N- versus C-domain selectivity of catalytic inactivation of human angiotensin converting enzyme by lisinopril-coupled transition metal chelates.

PubMed

Hocharoen, Lalintip; Joyner, Jeff C; Cowan, J A

2013-12-27

The N- and C-terminal domains of human somatic angiotensin I converting enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates was tested for both reversible binding and irreversible catalytic inactivation of each domain of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and catalytic factors (double-filter effect).

STRUCTURAL AND FUNCTIONAL CONSEQUENCES OF CIRCULAR PERMUTATION ON THE ACTIVE SITE OF OLD YELLOW ENZYME.

PubMed

Daugherty, Ashley B; Horton, John R; Cheng, Xiaodong; Lutz, Stefan

2015-02-06

Circular permutation of the NADPH-dependent oxidoreductase Old Yellow Enzyme from Saccharomyces pastorianus (OYE1) can significantly enhance the enzyme's catalytic performance. Termini relocation into four regions of the protein (sectors I-IV) near the active site has proven effective in altering enzyme function. To better understand the structural consequences and rationalize the observed functional gains in these OYE1 variants, we selected representatives from sectors I-III for further characterization by biophysical methods and X-ray crystallography. These investigations not only show trends in enzyme stability and quaternary structure as a function of termini location, but also provide a possible explanation for the catalytic gains in our top-performing OYE variant (new N-terminus at residue 303; sector III). Crystallographic analysis indicates that termini relocation into sector III affects the loop β6 region (amino acid positions: 290-310) of OYE1 which forms a lid over the active site. Peptide backbone cleavage greatly enhances local flexibility, effectively converting the loop into a tether and consequently increasing the environmental exposure of the active site. Interestingly, such active site remodeling does not negatively impact the enzyme's activity and stereoselectivity, nor does it perturb the conformation of other key active site residues with the exception of Y375. These observations were confirmed in truncation experiments, deleting all residues of the loop β6 region in our OYE variant. Intrigued by the finding that circular permutation leaves most of the key catalytic residues unchanged, we also tested OYE permutants for possible additive or synergistic effects of amino acid substitutions. Distinct functional changes in these OYE variants were detected upon mutations at W116, known in native OYE1 to cause inversion of diastereo-selectivity for ( S )-carvone reduction. Our findings demonstrate the contribution of loop β6 toward determining the

The linkage disequilibrium pattern of the angiotensin converting enzyme gene in Arabic and Asian population groups.

PubMed

Kharrat, Najla; Abdelmouleh, Wafa; Abdelhedi, Rania; Alfadhli, Suad; Rebai, Ahmed

2012-01-01

DNA variations within the Angiotensin-Converting Enzyme (ACE) gene have been shown to be involved in the aetiology of several common diseases and the therapeutic response. This study reports a comparison of haplotype analysis of five SNPs in the ACE gene region using a sample of 100 healthy subjects derived from five different populations (Tunisian, Iranian, Kuwaiti, Bahraini and Indian). Strong linkage disequilibrium was found among all SNPs studied for all populations. Two SNPs (rs1800764 and rs4340) were identified as key SNPs for all populations. These SNPs will be valuable for future effective association studies of the ACE gene polymorphisms in Arab and Asian populations.

Bacillus subtilis mutant LicT antiterminators exhibiting enzyme I- and HPr-independent antitermination affect catabolite repression of the bglPH operon.

PubMed

Lindner, Cordula; Hecker, Michael; Le Coq, Dominique; Deutscher, Josef

2002-09-01

The Bacillus subtilis antiterminator LicT regulates the expression of bglPH and bglS, which encode the enzymes for the metabolism of aryl-beta-glucosides and the beta-glucanase BglS. The N-terminal domain of LicT (first 55 amino acids) prevents the formation of rho-independent terminators on the respective transcripts by binding to target sites overlapping these terminators. Proteins of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) regulate the antitermination activity of LicT by phosphorylating histidines in its two PTS regulation domains (PRDs). Phosphorylation at His-100 in PRD-1 requires the PTS proteins enzyme I and HPr and the phosphorylated permease BglP and inactivates LicT. During transport and phosphorylation of aryl-beta-glucosides, BglP is dephosphorylated, which renders LicT active and thus leads to bglPH and bglS induction. In contrast, phosphorylation at His-207 and/or His-269 in PRD-2, which requires only enzyme I and HPr, is absolutely necessary for LicT activity and bglPH and bglS expression. We isolated spontaneous licT mutants expressing bglPH even when enzyme I and HPr were absent (as indicated by the designation "Pia" [PTS-independent antitermination]). Introduced in a ptsHI(+) strain, two classes of licT(Pia) mutations could be distinguished. Mutants synthesizing LicT(Pia) antiterminators altered in PRD-2 still required induction by aryl-beta-glucosides, whereas mutations affecting PRD-1 caused constitutive bglPH expression. One of the two carbon catabolite repression (CCR) mechanisms operative for bglPH requires the rho-independent terminator and is probably prevented when LicT is activated by P approximately His-HPr-dependent phosphorylation in PRD-2 (where the prefix "P approximately " stands for "phospho"). During CCR, the small amount of P approximately His-HPr present in cells growing on repressing PTS sugars probably leads to insufficient phosphorylation at PRD-2 of LicT and therefore to reduced bglPH expression

Bacillus subtilis Mutant LicT Antiterminators Exhibiting Enzyme I- and HPr-Independent Antitermination Affect Catabolite Repression of the bglPH Operon

PubMed Central

Lindner, Cordula; Hecker, Michael; Le Coq, Dominique; Deutscher, Josef

2002-01-01

The Bacillus subtilis antiterminator LicT regulates the expression of bglPH and bglS, which encode the enzymes for the metabolism of aryl-β-glucosides and the β-glucanase BglS. The N-terminal domain of LicT (first 55 amino acids) prevents the formation of ρ-independent terminators on the respective transcripts by binding to target sites overlapping these terminators. Proteins of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) regulate the antitermination activity of LicT by phosphorylating histidines in its two PTS regulation domains (PRDs). Phosphorylation at His-100 in PRD-1 requires the PTS proteins enzyme I and HPr and the phosphorylated permease BglP and inactivates LicT. During transport and phosphorylation of aryl-β-glucosides, BglP is dephosphorylated, which renders LicT active and thus leads to bglPH and bglS induction. In contrast, phosphorylation at His-207 and/or His-269 in PRD-2, which requires only enzyme I and HPr, is absolutely necessary for LicT activity and bglPH and bglS expression. We isolated spontaneous licT mutants expressing bglPH even when enzyme I and HPr were absent (as indicated by the designation “Pia” [PTS-independent antitermination]). Introduced in a ptsHI+ strain, two classes of licT(Pia) mutations could be distinguished. Mutants synthesizing LicT(Pia) antiterminators altered in PRD-2 still required induction by aryl-β-glucosides, whereas mutations affecting PRD-1 caused constitutive bglPH expression. One of the two carbon catabolite repression (CCR) mechanisms operative for bglPH requires the ρ-independent terminator and is probably prevented when LicT is activated by P∼His-HPr-dependent phosphorylation in PRD-2 (where the prefix “P∼” stands for “phospho”). During CCR, the small amount of P∼His-HPr present in cells growing on repressing PTS sugars probably leads to insufficient phosphorylation at PRD-2 of LicT and therefore to reduced bglPH expression. In agreement with this concept

Resistance to AFN-1252 Arises from Missense Mutations in Staphylococcus aureus Enoyl-acyl Carrier Protein Reductase (FabI)*

PubMed Central

Yao, Jiangwei; Maxwell, John B.; Rock, Charles O.

2013-01-01

AFN-1252 is a potent antibiotic against Staphylococcus aureus that targets the enoyl-acyl carrier protein reductase (FabI). A thorough screen for AFN-1252-resistant strains was undertaken to identify the spectrum of mechanisms for acquired resistance. A missense mutation in fabI predicted to encode FabI(M99T) was isolated 49 times, and a single isolate was predicted to encode FabI(Y147H). AFN-1252 only bound to the NADPH form of FabI, and the close interactions between the drug and Met-99 and Tyr-147 explained how the mutations would result in resistant enzymes. The clone expressing FabI(Y147H) had a pronounced growth defect that was rescued by exogenous fatty acid supplementation, and the purified protein had less than 5% of the enzymatic activity of FabI. FabI(Y147F) was also catalytically defective but retained its sensitivity to AFN-1252, illustrating the importance of the conserved Tyr-147 hydroxyl group in FabI function. The strains expressing FabI(M99T) exhibited normal growth, and the biochemical properties of the purified protein were indistinguishable from those of FabI. The AFN-1252 Kiapp increased from 4 nm in FabI to 69 nm in FabI(M99T), accounting for the increased resistance of the corresponding mutant strain. The low activity of FabI(Y147H) precluded an accurate Ki measurement. The strain expressing FabI(Y147H) was also resistant to triclosan; however, the strain expressing FabI(M99T) was more susceptible. Strains with higher levels of AFN-1252 resistance were not obtained. The AFN-1252-resistant strains remained sensitive to submicromolar concentrations of AFN-1252, which blocked growth through inhibition of fatty acid biosynthesis at the FabI step. PMID:24189061

Effects of angiotensin-converting enzyme inhibition on transient ischemia: the Quinapril Anti-Ischemia and Symptoms of Angina Reduction (QUASAR) trial.

PubMed

Pepine, Carl J; Rouleau, Jean-Lucien; Annis, Karen; Ducharme, Anique; Ma, Patrick; Lenis, Jacques; Davies, Richard; Thadani, Udho; Chaitman, Bernard; Haber, Harry E; Freedman, S Ben; Pressler, Milton L; Pitt, Bertram

2003-12-17

We sought to determine whether angiotensin-converting enzyme inhibition (ACE-I) (i.e., quinapril) prevents transient ischemia (exertional and spontaneous) in patients with coronary artery disease (CAD). It is known that ACE-I reduces the risk of death, myocardial infarction (MI), and other CAD-related outcomes in high-risk patients. Numerous studies have confirmed that ACE-I improves coronary flow and endothelial function. Whether ACE-I also decreases transient ischemia is unclear, because no studies have been adequately designed or sufficiently powered to evaluate this issue. Using a randomized, double-blinded, placebo-controlled, multicenter design, we enrolled 336 CAD patients with stable angina. None had uncontrolled hypertension, left ventricular (LV) dysfunction, or recent MI, and all developed electrocardiographic (ECG) evidence of ischemia during exercise. They were randomly assigned to one of two groups: 40 mg/day quinapril (n = 177) or placebo (n = 159) for 8 weeks. Patients then entered an additional eight-week treatment phase to examine the full dose range. Those assigned to 40 mg quinapril continued that dose and those assigned to placebo were titrated to 80 mg/day. Treadmill testing, the Seattle Angina Questionnaire, and ambulatory ECG monitoring were used to assess responses at baseline and at 8 and 16 weeks. The groups did not differ significantly at entry or in terms of indexes assessing myocardial ischemia at 8 or 16 weeks of treatment. In this low-risk population, ACE-I was not associated with serious adverse events. Our findings suggest short-term ACE-I in CAD patients without hypertension, LV dysfunction, or acute MI is not associated with significant effects on transient ischemia.

Use of mutation spectra analysis software.

PubMed

Rogozin, I; Kondrashov, F; Glazko, G

2001-02-01

The study and comparison of mutation(al) spectra is an important problem in molecular biology, because these spectra often reflect on important features of mutations and their fixation. Such features include the interaction of DNA with various mutagens, the function of repair/replication enzymes, and properties of target proteins. It is known that mutability varies significantly along nucleotide sequences, such that mutations often concentrate at certain positions, called "hotspots," in a sequence. In this paper, we discuss in detail two approaches for mutation spectra analysis: the comparison of mutation spectra with a HG-PUBL program, (FTP: sunsite.unc.edu/pub/academic/biology/dna-mutations/hyperg) and hotspot prediction with the CLUSTERM program (www.itba.mi.cnr.it/webmutation; ftp.bionet.nsc.ru/pub/biology/dbms/clusterm.zip). Several other approaches for mutational spectra analysis, such as the analysis of a target protein structure, hotspot context revealing, multiple spectra comparisons, as well as a number of mutation databases are briefly described. Mutation spectra in the lacI gene of E. coli and the human p53 gene are used for illustration of various difficulties of such analysis. Copyright 2001 Wiley-Liss, Inc.

Bioengineering Anabolic Vitamin D-25-Hydroxylase Activity into the Human Vitamin D Catabolic Enzyme, Cytochrome P450 CYP24A1, by a V391L Mutation*

PubMed Central

Kaufmann, Martin; Prosser, David E.; Jones, Glenville

2011-01-01

CYP24A1 is a mitochondrial cytochrome P450 (CYP) that catabolizes 1α,25-dihydroxyvitamin D3 (1α,25-(OH)2D3) to different products: calcitroic acid or 1α,25-(OH)2D3-26,23-lactone via multistep pathways commencing with C24 and C23 hydroxylation, respectively. Despite the ability of CYP24A1 to catabolize a wide range of 25-hydroxylated analogs including 25-hydroxyvitamin D3, the enzyme is unable to metabolize the synthetic prodrug, 1α-hydroxyvitamin D3 (1α-OH-D3), presumably because it lacks a C25-hydroxyl. In the current study we show that a single V391L amino acid substitution in the β3a-strand of human CYP24A1 converts this enzyme from a catabolic 1α,25-(OH)2D3-24-hydroxylase into an anabolic 1α-OH-D3-25-hydroxylase, thereby forming the hormone, 1α,25-(OH)2D3. Furthermore, because the mutant enzyme retains its basal ability to catabolize 1α,25-(OH)2D3 via C24 hydroxylation, it can also make calcitroic acid. Previous work has shown that an A326G mutation is responsible for the regioselectivity differences observed between human (primarily C24-hydroxylating) and opossum (C23-hydroxylating) CYP24A1. When the V391L and A326G mutations were combined (V391L/A326G), the mutant enzyme continued to form 1α,25-(OH)2D3 from 1α-OH-D3, but this initial product was diverted via the C23 hydroxylation pathway into the 26,23-lactone. The relative position of Val-391 in the β3a-strand of a homology model and the crystal structure of rat CYP24A1 is consistent with hydrophobic contact of Val-391 and the substrate side chain near C21. We interpret that the substrate specificity of V391L-modified human CYP24A1 toward 1α-OH-D3 is enabled by an altered contact with the substrate side chain that optimally positions C25 of the 1α-OH-D3 above the heme for hydroxylation. PMID:21697097

Quantitative assessment of the association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive system cancer risk.

PubMed

Wang, J; Yang, S; Guo, F H; Mao, X; Zhou, H; Dong, Y Q; Wang, Z M; Luo, F

2015-11-13

The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been reported to be associated with digestive system cancer; however, the results from previous studies have been conflicting. The present study aimed to investigate the association between the ACE I/D polymorphism and the risk of digestive system cancer using a meta-analysis of previously published studies. Databases were systematically searched to identify relevant studies published prior to December 2014. We estimated the pooled OR with its 95%CI to assess the association. The meta-analysis consisted of thirteen case-control studies that included 2557 patients and 4356 healthy controls. Meta-analysis results based on all the studies showed no significant association between the ACE I/D polymorphism and the risk of digestive system cancer (DD vs II: OR = 0.85, 95%CI = 0.59-1.24; DI vs II: OR = 0.94, 95%CI = 0.78-1.15; dominant model: OR = 0.96, 95%CI = 0.81- 1.15; recessive model: OR = 1.06, 95%CI = 0.76-1.48). Subgroup analyses by race and cancer type did not detect an association between the ACE I/D polymorphism and digestive system cancer risk. However, when the analyses were restricted to smaller studies (N < 500 patients), the summary OR of DI vs II was 0.80 (95%CI = 0.66-0.97). Our analyses detected a possibility of publication bias with a misestimate of the true association by smaller studies. Overall, meta-analysis results suggest the ACE I/D polymorphism might not be associated with susceptibility to digestive system cancer. Further large and well-designed studies are needed to confirm these conclusions.

Angiotensin converting enzyme insertion/deletion polymorphism is associated with increased adiposity and blood pressure in obese children and adolescents.

PubMed

Lemes, Vinícius A F; Neves, Ana Luísa; Guazzelli, Isabel C; Frazzatto, Eliana; Nicolau, Christiane; Corrêa-Giannella, Maria Lúcia; Velho, Gilberto; Villares, Sandra M F

2013-12-15

The insertion/deletion polymorphism in the gene encoding the angiotensin-converting enzyme (ACE I/D) was associated with arterial hypertension and obesity in adults, but the data in children are scarce and yielded contrasting results. We assessed the impact of the ACE I/D on blood pressure and obesity related traits in a Brazilian cohort of obese children and adolescents. ACE I/D was genotyped in 320 obese children and adolescents (64% of girls) aged 7-16years, referred for a weight-loss program. We observed an association of the D-allele with blood pressure and with pre-hypertension/hypertension in boys (odds ratio 2.44, 95% C.I. 1.34-4.68, p=0.005 for a codominant model). The D-allele, insulin resistance and body fat mass had independent and additive effects and explained 14% of the variance of pre-hypertension/hypertension. The BMI, waist circumference, and body fat mass were significantly higher in DD/ID boys than in II boys (p<0.005). Allelic associations with obesity related traits were independent of the association with blood pressure. No genotype associations were observed in girls. The D-allele of the ACE I/D polymorphism was associated with arterial hypertension and with obesity related traits in boys, but not in girls, in a cohort of obese children and adolescents. These associations were independent of each other, as well as of the effects of other confounding traits such as insulin secretion, insulin sensitivity and glucose tolerance. Our results are in agreement with experimental evidences suggesting that the renin-angiotensin system plays a role in the regulation of visceral adipose tissue accumulation. © 2013.

Angiotensin-converting enzyme gene polymorphism (insertion/deletion) and liver fibrosis in Turkish patients from the western Black Sea region, Turkey.

PubMed

Turhan, N K; Ilikhan, S Uygun; Hamamcioglu, A C; Ustundag, Y; Dursun, A; Kokturk, F

2015-12-16

Chronic viral hepatitis B, chronic viral hepatitis C, non-alcoholic steatohepatitis, alcoholic liver disease, autoimmune hepatitis, primary biliary cirrhosis, and secondary biliary cirrhosis are important health issues worldwide. While an association between angiotensin-converting enzyme gene insertion/deletion (ACE gene I/D) polymorphism and liver fibrosis has been demonstrated in rat studies, the results of clinical studies area have been contradictory. The aim of this study was to assess the possible association between ACE gene I/D polymorphism and liver fibrosis in a large group of Turkish patients from the western Black Sea region. In 418 patients with different etiologies, ACE gene I/D polymorphism and serum ACE levels were investigated. The distribution of the "DD", "ID", "II" genotypes of the ACE gene were 32.5, 48.8, and 18.7% in the mild to moderate fibrosis group (N = 246, F:1-3 according to Ishak's score) and 39.0, 44.2, and 16.9% in the advanced fibrosis group (N = 172, F:4-6 according to Ishak's score). A significant correlation between serum ACE levels and ACE gene alleles was identified (P < 0.001): serum ACE levels of patients with D alleles were higher than those of patients with I alleles [44 (min 7-max 101) versus 29 (min 7-max 96)]. Patients with advanced fibrosis were also found to be older than those with mild to moderate fibrosis (P < 0.001). No significant association was noted between the patient gender and fibrosis severity. We conclude that ACE I/D polymorphism is not associated with the degree of liver fibrosis.

Angiotensin-converting Enzyme Inhibition Improves the Effectiveness of Transcutaneous Carbon Dioxide Treatment.

PubMed

Nemeth, Balazs; Kiss, Istvan; Jencsik, Timea; Peter, Ivan; Kreska, Zita; Koszegi, Tamas; Miseta, Attila; Kustan, Peter; Boncz, Imre; Laczo, Andrea; Ajtay, Zeno

2017-01-01

To study the effect of carbon dioxide (CO 2 ) therapy on the nitric oxide (NO) pathway by monitoring plasma asymmetric dimethylarginine (ADMA) concentrations. Forty-seven hypertensive patients who underwent transcutaneous CO 2 therapy were enrolled. Thirty healthy individuals were recruited for the control group. Blood samples were taken one hour before, as well as one hour, 24 hours and 3 weeks after the first CO 2 treatment. Controls did not undergo CO 2 treatment. Plasma ADMA levels were measured by ELISA. ADMA levels decreased significantly one hour after the first CO2 treatment compared to the baseline concentrations (p=0.003). Significantly greater reduction was found among patients in whom angiotensin converting enzyme inhibitors (ACEIs) were administered (p=0.019). The short- and long-term decrease of ADMA levels suggests that CO 2 is not only a vasodilator, but also has a beneficial effect on the NO pathway. ACE inhibition seems to enhance the effect of CO 2 treatment. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Substrate metabolism, hormone interaction, and angiotensin-converting enzyme inhibitors in left ventricular hypertrophy.

PubMed

Zhu, Y C; Zhu, Y Z; Spitznagel, H; Gohlke, P; Unger, T

1996-01-01

Left ventricular hypertrophy is considered to be an independent risk factor giving rise to ischemia, arrhythmias, and left ventricular dysfunction. Slow movement of intracellular calcium contributes to the impaired contraction and relaxation function of hypertrophied myocardium. Myofibril content may also be shifted to fetal-type isoforms with decreased contraction and relaxation properties in left ventricular hypertrophy. Myocyte hypertrophy and interstitial fibrosis are regulated independently by mechanical and neurohumoral mechanisms. In severely hypertrophied myocardium, capillary density is reduced, the diffusion distance for oxygen, nutrients, and metabolites is increased, and the ratio of energy-production sites to energy-consumption sites is decreased. The metabolic state of severely hypertrophied myocardium is anaerobic, as indicated by the shift of lactate dehydrogenase marker enzymes. Therefore, the hypertrophied myocardium is more vulnerable to ischemic events. As a compensatory response to severe cardiac hypertrophy and congestive heart failure, the ADP/ATP carrier is activated and atrial natriuretic peptide is released to increase high-energy phosphate production and reduce cardiac energy consumption by vasodilation and sodium and fluid elimination. However, in severely hypertrophied and failing myocardium, vasoconstrictor and sodium- and fluid-retaining factors, such as the renin-angiotensin system, aldosterone, and sympathetic nerve activity, play an overwhelming role. Angiotensin-converting enzyme inhibitors (ACEIs) are able to prevent cardiac hypertrophy and improve cardiac function and metabolism. Under experimental conditions, these beneficial effects can be ascribed mainly to bradykinin potentiation, although a contribution of the ACEI-induced angiotensin II reduction cannot be excluded.

Impact of angiotensin and endothelin converting enzymes and related bradykinin on renal functions in L-NAME hypertensive rats

NASA Astrophysics Data System (ADS)

Omar, Ali Zainal; Maulood, Ismail M.

2017-09-01

The renin-angiotensin system (RAS), one of the most important hormonal systems, controls the kidney functions by regulating fluid volume, and electrolyte balance. The current study included the effects of kinin-kallikrein system (KKS) and its interaction with both angiotensin converting enzyme (ACE) and endothelin converting enzyme (ECE) on some of kidney function test parameters. In the present experiment, rats were divided into six groups, the first group was infused with normal saline, the second group was L-NG-Nitroarginine methyl ester (L-NAME) treated rats, third group was bradykinin (BK), forth group was captopril (ACEi), fifth group was phosphoramidon (ECEi), sixth group was a combination of BK with phosphoramidon. L-NAME was intravenously infused for one hour to develop systematic hypertension in male rats. After one hour of infusion, the results showed that L-NAME significantly increased serum creatinine. While, it decreased glomerular filtration rate (GFR), and K+ excretion rate. Moreover, BK increased packed cell volume PCV%, serum creatinine and K+ ion concentration. While, it reduced GFR, serum Ca+2 ion concentration, K+ and Na+ excretion rates. On the other hand, captopril infusion showed its effect by reduction in GFR, serum Ca+2 ion and electrolyte excretion rates. Phosphoramidon an ECEi dramatically reduced serum Ca+2 ion, but it increased pH, GFR and Ca+2 excretion rate. The results suggested that BK and Captopril each alone severely reduces GFR value. Interestingly, inhibition of ET-1 production via phosphoramidon could markedly elevate GFR values.

Structural Basis of Glyphosate Resistance Resulting from the Double Mutation Thr97 → Ile and Pro101 → Ser in 5-Enolpyruvylshikimate-3-phosphate Synthase from Escherichia coli*S⃞

PubMed Central

Funke, Todd; Yang, Yan; Han, Huijong; Healy-Fried, Martha; Olesen, Sanne; Becker, Andreas; Schönbrunn, Ernst

2009-01-01

The shikimate pathway enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is the target of the broad spectrum herbicide glyphosate. The genetic engineering of EPSPS led to the introduction of glyphosate-resistant crops worldwide. The genetically engineered corn lines NK603 and GA21 carry distinct EPSPS enzymes. CP4 EPSPS, expressed in NK603 corn and transgenic soybean, cotton, and canola, belongs to class II EPSPS, glyphosate-insensitive variants of this enzyme isolated from certain Gram-positive bacteria. GA21 corn, on the other hand, was created by point mutations of class I EPSPS, such as the enzymes from Zea mays or Escherichia coli, which are sensitive to low glyphosate concentrations. The structural basis of the glyphosate resistance resulting from these point mutations has remained obscure. We studied the kinetic and structural effects of the T97I/P101S double mutation, the molecular basis for GA21 corn, using EPSPS from E. coli. The T97I/P101S enzyme is essentially insensitive to glyphosate (Ki = 2.4 mm) but maintains high affinity for the substrate phosphoenolpyruvate (PEP) (Km = 0.1 mm). The crystal structure at 1.7-Å resolution revealed that the dual mutation causes a shift of residue Gly96 toward the glyphosate binding site, impairing efficient binding of glyphosate, while the side chain of Ile97 points away from the substrate binding site, facilitating PEP utilization. The single site T97I mutation renders the enzyme sensitive to glyphosate and causes a substantial decrease in the affinity for PEP. Thus, only the concomitant mutations of Thr97 and Pro101 induce the conformational changes necessary to produce catalytically efficient, glyphosate-resistant class I EPSPS. PMID:19211556

The Relay/Converter Interface Influences Hydrolysis of ATP by Skeletal Muscle Myosin II.

PubMed

Bloemink, Marieke J; Melkani, Girish C; Bernstein, Sanford I; Geeves, Michael A

2016-01-22

The interface between relay and converter domain of muscle myosin is critical for optimal myosin performance. Using Drosophila melanogaster indirect flight muscle S1, we performed a kinetic analysis of the effect of mutations in the converter and relay domain. Introduction of a mutation (R759E) in the converter domain inhibits the steady-state ATPase of myosin S1, whereas an additional mutation in the relay domain (N509K) is able to restore the ATPase toward wild-type values. The R759E S1 construct showed little effect on most steps of the actomyosin ATPase cycle. The exception was a 25-30% reduction in the rate constant of the hydrolysis step, the step coupled to the cross-bridge recovery stroke that involves a change in conformation at the relay/converter domain interface. Significantly, the double mutant restored the hydrolysis step to values similar to the wild-type myosin. Modeling the relay/converter interface suggests a possible interaction between converter residue 759 and relay residue 509 in the actin-detached conformation, which is lost in R759E but is restored in N509K/R759E. This detailed kinetic analysis of Drosophila myosin carrying the R759E mutation shows that the interface between the relay loop and converter domain is important for fine-tuning myosin kinetics, in particular ATP binding and hydrolysis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Preparation of lisinopril-capped gold nanoparticles for molecular imaging of angiotensin-converting enzyme

NASA Astrophysics Data System (ADS)

Li, Yuan; Baeta, Cesar; Aras, Omer; Daniel, Marie-Christine

2009-05-01

Overexpression of angiotensin-converting enzyme (ACE) has been associated with the pathophysiology of cardiac and pulmonary fibrosis. Moreover, the prescription of ACE inhibitors, such as lisinopril, has shown a favorable effect on patient outcome for patients with heart failure or systemic hypertension. Thus targeted imaging of the ACE would be of crucial importance for monitoring tissue ACE activity as well as the treatment efficacy in heart failure. In this respect, lisinopril-coated gold nanoparticles were prepared to provide a new type of probe for targeted molecular imaging of ACE by tuned K-edge computed tomography (CT) imaging. The preparation involved non-modified lisinopril, using its primary amine group as the anchoring function on the gold nanoparticles surface. The stable lisinopril-coated gold nanoparticles obtained were characterized by UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM). Their zeta potential was also measured in order to assess the charge density on the modified gold nanoparticles (GNPs).

EGFR T790M mutation testing within the osimertinib AURA Phase I study.

PubMed

Dearden, Simon; Brown, Helen; Jenkins, Suzanne; Thress, Kenneth S; Cantarini, Mireille; Cole, Rebecca; Ranson, Malcolm; Jänne, Pasi A

2017-07-01

Reliable epidermal growth factor receptor (EGFR) mutation testing techniques are required to identify eligible patients with EGFR mutation/T790M positive advanced non-small cell lung cancer (NSCLC), for treatment with osimertinib (AZD9291), an oral, potent, irreversible EGFR tyrosine kinase inhibitor (TKI) selective for EGFR-TKI-sensitizing and T790M resistance mutations over wild-type EGFR. There is no current consensus regarding the best method to detect EGFR T790M mutations. The aim of this study was to describe the concordance between local testing, which used a variety of methods, and central testing, using the cobas ® EGFR Mutation Test, for EGFR-sensitizing mutations and the T790M resistance mutation. Tumor samples were obtained from all patients screened for inclusion onto the osimertinib Phase I expansion component of the AURA Phase I/II study (NCT01802632). Samples underwent central laboratory testing for EGFR-sensitizing mutations and T790M resistance mutation using the cobas ® EGFR Mutation Test. Results were compared with local laboratory test results, based on other testing methodologies including Sanger sequencing, therascreen ® , PNAClamp™, and Sequenom MassARRAY ® . Central laboratory testing was successful in 99% of samples passing histopathology review and testing success rates were comparable across the three central laboratories. Concordance between central and local testing for common sensitizing mutations was high (>98%) and concordance for the T790M mutation was also high (>90%). Tumor heterogeneity, along with other technical factors may have influenced this result. Within the osimertinib AURA Phase I study, EGFR mutation testing across three centralized laboratories using the cobas ® EGFR Mutation Test was feasible and successful, with strong concordance between local and central laboratory results, including for T790M. The cobas ® EGFR Mutation Test has subsequently been approved as the companion diagnostic test for osimertinib in

Angiotensin I-converting-enzyme-inhibitory and antibacterial peptides from Lactobacillus helveticus PR4 proteinase-hydrolyzed caseins of milk from six species.

PubMed

Minervini, F; Algaron, F; Rizzello, C G; Fox, P F; Monnet, V; Gobbetti, M

2003-09-01

Sodium caseinates prepared from bovine, sheep, goat, pig, buffalo or human milk were hydrolyzed by a partially purified proteinase of Lactobacillus helveticus PR4. Peptides in each hydrolysate were fractionated by reversed-phase fast-protein liquid chromatography. The fractions which showed the highest angiotensin I-converting-enzyme (ACE)-inhibitory or antibacterial activity were sequenced by mass spectrum and Edman degradation analyses. Various ACE-inhibitory peptides were found in the hydrolysates: the bovine alpha(S1)-casein (alpha(S1)-CN) 24-47 fragment (f24-47), f169-193, and beta-CN f58-76; ovine alpha(S1)-CN f1-6 and alpha(S2)-CN f182-185 and f186-188; caprine beta-CN f58-65 and alpha(S2)-CN f182-187; buffalo beta-CN f58-66; and a mixture of three tripeptides originating from human beta-CN. A mixture of peptides with a C-terminal sequence, Pro-Gly-Pro, was found in the most active fraction of the pig sodium caseinate hydrolysate. The highest ACE-inhibitory activity of some peptides corresponded to the concentration of the ACE inhibitor (S)-N-(1-[ethoxycarbonyl]-3-phenylpropyl)-ala-pro maleate (enalapril) of 49.253 micro g/ml (100 micro mol/liter). Several of the above sequences had features in common with other ACE-inhibitory peptides reported in the literature. The 50% inhibitory concentration (IC(50)) of some of the crude peptide fractions was very low (16 to 100 micro g/ml). Some identified peptides were chemically synthesized, and the ACE-inhibitory activity and IC(50)s were confirmed. An antibacterial peptide corresponding to beta-CN f184-210 was identified in human sodium caseinate hydrolysate. It showed a very large spectrum of inhibition against gram-positive and -negative bacteria, including species of potential clinical interest, such as Enterococcus faecium, Bacillus megaterium, Escherichia coli, Listeria innocua, Salmonella spp., Yersinia enterocolitica, and Staphylococcus aureus. The MIC for E. coli F19 was ca. 50 micro g/ml. Once generated

Angiotensin I-Converting-Enzyme-Inhibitory and Antibacterial Peptides from Lactobacillus helveticus PR4 Proteinase-Hydrolyzed Caseins of Milk from Six Species

PubMed Central

Minervini, F.; Algaron, F.; Rizzello, C. G.; Fox, P. F.; Monnet, V.; Gobbetti, M.

2003-01-01

Sodium caseinates prepared from bovine, sheep, goat, pig, buffalo or human milk were hydrolyzed by a partially purified proteinase of Lactobacillus helveticus PR4. Peptides in each hydrolysate were fractionated by reversed-phase fast-protein liquid chromatography. The fractions which showed the highest angiotensin I-converting-enzyme (ACE)-inhibitory or antibacterial activity were sequenced by mass spectrum and Edman degradation analyses. Various ACE-inhibitory peptides were found in the hydrolysates: the bovine αS1-casein (αS1-CN) 24-47 fragment (f24-47), f169-193, and β-CN f58-76; ovine αS1-CN f1-6 and αS2-CN f182-185 and f186-188; caprine β-CN f58-65 and αS2-CN f182-187; buffalo β-CN f58-66; and a mixture of three tripeptides originating from human β-CN. A mixture of peptides with a C-terminal sequence, Pro-Gly-Pro, was found in the most active fraction of the pig sodium caseinate hydrolysate. The highest ACE-inhibitory activity of some peptides corresponded to the concentration of the ACE inhibitor (S)-N-(1-[ethoxycarbonyl]-3-phenylpropyl)-ala-pro maleate (enalapril) of 49.253 μg/ml (100 μmol/liter). Several of the above sequences had features in common with other ACE-inhibitory peptides reported in the literature. The 50% inhibitory concentration (IC50) of some of the crude peptide fractions was very low (16 to 100 μg/ml). Some identified peptides were chemically synthesized, and the ACE-inhibitory activity and IC50s were confirmed. An antibacterial peptide corresponding to β-CN f184-210 was identified in human sodium caseinate hydrolysate. It showed a very large spectrum of inhibition against gram-positive and -negative bacteria, including species of potential clinical interest, such as Enterococcus faecium, Bacillus megaterium, Escherichia coli, Listeria innocua, Salmonella spp., Yersinia enterocolitica, and Staphylococcus aureus. The MIC for E. coli F19 was ca. 50 μg/ml. Once generated, the bioactive peptides were resistant to further

Molecular dynamics investigation of the ionic liquid/enzyme interface: application to engineering enzyme surface charge.

PubMed

Burney, Patrick R; Nordwald, Erik M; Hickman, Katie; Kaar, Joel L; Pfaendtner, Jim

2015-04-01

Molecular simulations of the enzymes Candida rugosa lipase and Bos taurus α-chymotrypsin in aqueous ionic liquids 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium ethyl sulfate were used to study the change in enzyme-solvent interactions induced by modification of the enzyme surface charge. The enzymes were altered by randomly mutating lysine surface residues to glutamate, effectively decreasing the net surface charge by two for each mutation. These mutations resemble succinylation of the enzyme by chemical modification, which has been shown to enhance the stability of both enzymes in ILs. After establishing that the enzymes were stable on the simulated time scales, we focused the analysis on the organization of the ionic liquid substituents about the enzyme surface. Calculated solvent charge densities show that for both enzymes and in both solvents that changing positively charged residues to negative charge does indeed increase the charge density of the solvent near the enzyme surface. The radial distribution of IL constituents with respect to the enzyme reveals decreased interactions with the anion are prevalent in the modified systems when compared to the wild type, which is largely accompanied by an increase in cation contact. Additionally, the radial dependence of the charge density and ion distribution indicates that the effect of altering enzyme charge is confined to short range (≤1 nm) ordering of the IL. Ultimately, these results, which are consistent with that from prior experiments, provide molecular insight into the effect of enzyme surface charge on enzyme stability in ILs. © 2015 Wiley Periodicals, Inc.

Improvement of enzyme activity of β-1,3-1,4-glucanase from Paenibacillus sp. X4 by error-prone PCR and structural insights of mutated residues.

PubMed

Baek, Seung Cheol; Ho, Thien-Hoang; Lee, Hyun Woo; Jung, Won Kyeong; Gang, Hyo-Seung; Kang, Lin-Woo; Kim, Hoon

2017-05-01

β-1,3-1,4-Glucanase (BGlc8H) from Paenibacillus sp. X4 was mutated by error-prone PCR or truncated using termination primers to improve its enzyme properties. The crystal structure of BGlc8H was determined at a resolution of 1.8 Å to study the possible roles of mutated residues and truncated regions of the enzyme. In mutation experiments, three clones of EP 2-6, 2-10, and 5-28 were finally selected that exhibited higher specific activities than the wild type when measured using their crude extracts. Enzyme variants of BG 2-6 , BG 2-10 , and BG 5-28 were mutated at two, two, and six amino acid residues, respectively. These enzymes were purified homogeneously by Hi-Trap Q and CHT-II chromatography. Specific activity of BG 5-28 was 2.11-fold higher than that of wild-type BG wt , whereas those of BG 2-6 and BG 2-10 were 0.93- and 1.19-fold that of the wild type, respectively. The optimum pH values and temperatures of the variants were nearly the same as those of BG wt (pH 5.0 and 40 °C, respectively). However, the half-life of the enzyme activity and catalytic efficiency (k cat /K m ) of BG 5-28 were 1.92- and 2.12-fold greater than those of BG wt at 40 °C, respectively. The catalytic efficiency of BG 5-28 increased to 3.09-fold that of BG wt at 60 °C. These increases in the thermostability and catalytic efficiency of BG 5-28 might be useful for the hydrolysis of β-glucans to produce fermentable sugars. Of the six mutated residues of BG 5-28 , five residues were present in mature BGlc8H protein, and two of them were located in the core scaffold of BGlc8H and the remaining three residues were in the substrate-binding pocket forming loop regions. In truncation experiments, three forms of C-terminal truncated BGlc8H were made, which comprised 360, 286, and 215 amino acid residues instead of the 409 residues of the wild type. No enzyme activity was observed for these truncated enzymes, suggesting the complete scaffold of the α 6 /α 6 -double-barrel structure is

Attenuation of insulin-resistance-based hepatocarcinogenesis and angiogenesis by combined treatment with branched-chain amino acids and angiotensin-converting enzyme inhibitor in obese diabetic rats.

PubMed

Yoshiji, Hitoshi; Noguchi, Ryuichi; Kaji, Kosuke; Ikenaka, Yasuhide; Shirai, Yusaku; Namisaki, Tadashi; Kitade, Mitsuteru; Tsujimoto, Tatsuhiro; Kawaratani, Hideto; Fukui, Hiroshi

2010-04-01

Insulin resistance (IR) is reportedly involved in the progression of hepatocellular carcinoma (HCC). Because neovascularization plays an important role in HCC, including hepatocarcinogenesis, an angiostatic therapy would be a promising approach for chemoprevention against HCC. The aim of the present study was to examine the combined effect of clinically used branched-chain amino acids (BCAAs) and an angiotensin-converting enzyme inhibitor (ACE-I), in conjunction with neovascularization, on hepatocarcinogenesis under the condition of IR. The combined effect of the treatment on the development of liver enzyme-altered preneoplastic lesions, angiogenesis, and several indices was elucidated in obese diabetic rats. We also performed several sets of in vitro experiments to examine the mechanisms involved. When used individually, both BCAAs and ACE-I at clinically comparable low doses significantly attenuated the development of preneoplastic lesions, along with the suppression of both angiogenesis and vascular endothelial growth factor (VEGF) expression. The combination treatment with both agents exerted a more potent inhibitory effect than that of either single agent. Our in vitro study showed a similar combined effect on endothelial cell tubule formation. This combination regimen showed a marked chemopreventive effect against hepatocarcinogenesis, along with suppression of neovascularization and VEGF expression, in obese diabetic rats. Because both BCAAs and ACE-Is are widely used in clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against IR-based HCC in the future.

Expression, functional analysis and mutation of a novel neutral zearalenone-degrading enzyme.

PubMed

Wang, Meixing; Yin, Lifeng; Hu, Huizhen; Selvaraj, Jonathan Nimal; Zhou, Yuling; Zhang, Guimin

2018-06-24

The crops and grains were often contaminated by high level of mycotoxin zearalenone (ZEN). In order to remove ZEN and keep food safe, ZEN-degrading or detoxifying enzymes are urgently needed. Here, a newly identified lactonohydrolase responsible for the detoxification of ZEN, annotated as Zhd518, was expressed and characterized. Zhd518 showed 65% amino acid identity with Zhd101, which was widely studied for its ZEN-degrading ability. A detailed activity measurement method of ZEN-degrading enzyme was provided. Biochemical analysis indicated that the purified recombinant Zhd518 from E. coli exhibited a high activity against ZEN (207.0 U/mg), with the optimal temperature and pH of 40 °C and 8.0, respectively. The Zhd518 can degrade ZEN derivatives, and the specific activities against α-Zearalenol, β-Zearalenol, α-Zearalanol and β-Zearalanol were 23.0 U/mg, 64.7 U/mg, 119.8 U/mg and 66.5 U/mg, respectively. The active sites of Zhd518 were predicted by structure modeling and determined by mutation analysis. A point mutant N156H exhibited 3.3-fold activity against α-Zearalenol comparing to Zhd518. Zhd518 is the first reported neutral and the second characterized ZEN-degrading enzyme, which provides a new and more excellent candidate for ZEN detoxifying in food and feed industry. Copyright © 2018. Published by Elsevier B.V.

Effects of Cordyceps militaris (L.) Fr. fermentation on the nutritional, physicochemical, functional properties and angiotensin I converting enzyme inhibitory activity of red bean (Phaseolus angularis [Willd.] W.F. Wight.) flour.

PubMed

Xiao, Yu; Sun, Mingmei; Zhang, Qiuqin; Chen, Yulian; Miao, Junqing; Rui, Xin; Dong, Mingsheng

2018-04-01

The effects of solid-state fermentation with Cordyceps militaris (L.) Fr. on the nutritional, physicochemical, and functional properties as well as angiotensin I converting enzyme (ACE) inhibitory activity of red bean ( Phaseolus angularis [Willd.] W.F. Wight.) flour were determined. Fermentation increased the amount of small peptides but significantly decreased large peptides. Fermentation also increased proteins and essential amino acids (by 9.31 and 13.89%, respectively) and improved the in vitro protein digestibility (6.54%) of red beans. Moreover, fermentation increased the water holding capacity (from 2.36 to 2.59 mL/g), fat absorption capacity (from 84.65 to 114.55%), emulsion activity (from 10.96 to 52.77%), emulsion stability (from 5.43 to 53.82%), and foaming stability (from 11.95 to 20.68%). Fermented red bean flour achieved a lower least gelation concentration of 14% than that of the control (18%). In contrast to the non-fermented red bean, the fermented red bean showed ACE inhibitory activity, with IC 50 value of 0.63 mg protein/mL. Overall, fermentation improved the nutritional, physicochemical, and functional properties as well as the biological activity of red bean flour. Thus, fermented red bean flour may serve as a novel nutritional and functional ingredient for applications in food design.

Immobilized enzymes to convert N-sulfo, N-acetyl heparosan to a critical intermediate in the production of bioengineered heparin.

PubMed

Xiong, Jian; Bhaskar, Ujjwal; Li, Guoyun; Fu, Li; Li, Lingyun; Zhang, Fuming; Dordick, Jonathan S; Linhardt, Robert J

2013-09-10

Heparin is a critically important anticoagulant drug that is prepared from pig intestine. In 2007-2008, there was a crisis in the heparin market when the raw material was adulterated with the toxic polysaccharide, oversulfated chondroitin sulfate, which was associated with 100 deaths in the U.S. alone. As the result of this crisis, our laboratory and others have been actively pursuing alternative sources for this critical drug, including synthetic heparins and bioengineered heparin. In assessing the bioengineering processing costs it has become clear that the use of both enzyme-catalyzed cofactor recycling and enzyme immobilization will be needed for commercialization. In the current study, we examine the use of immobilization of C₅-epimerase and 2-O-sulfotransferase involved in the first enzymatic step in the bioengineered heparin process, as well as arylsulfotransferase-IV involved in cofactor recycling in all three enzymatic steps. We report the successful immobilization of all three enzymes and their use in converting N-sulfo, N-acetyl heparosan into N-sulfo, N-acetyl 2-O-sulfo heparin. Copyright © 2013 Elsevier B.V. All rights reserved.

Citrullinemia type I, classical variant. Identification of ASS-p~G390R (c.1168G>A) mutation in families of a limited geographic area of Argentina: a possible population cluster.

PubMed

Laróvere, Laura E; Angaroni, Celia J; Antonozzi, Sandra L; Bezard, Miriam B; Shimohama, Mariko; de Kremer, Raquel Dodelson

2009-07-01

Citrullinemia type I (CTLN1) is an urea cycle defect caused by mutations in the argininosuccinate synthetase gene. We report the first identification in Argentina of patients with CTLN1 in a limited geographic area. Molecular analysis in patient/relatives included PCR, sequencing and restriction enzyme assay. The studied families showed the same mutation: ASS~p.G390R, associated with the early-onset/severe phenotype. We postulate a possible population cluster. A program to know the carrier frequency in that population is in progress.

Genetic Polymorphism of Angiotensin-Converting Enzyme and Chronic Obstructive Pulmonary Disease Risk: An Updated Meta-Analysis

PubMed Central

Kang, Sang Wook; Kim, Su Kang; Jung, Hee-Jae; Kim, Kwan-Il; Kim, Jinju

2016-01-01

The relationship between polymorphism of the angiotensin I converting enzyme (ACE) gene and chronic obstructive pulmonary disease (COPD) has been examined in many previous studies. However, their results were controversial. Therefore, we performed a meta-analysis to evaluate the relationship between the ACE gene and the risk of COPD. Fourteen case-control studies were included in this meta-analysis. The pooled p value, odds ratio (OR), and 95% confidence interval (95% CI) were used to investigate the strength of the association. The meta-analysis was performed using comprehensive meta-analysis software. Our meta-analysis results revealed that ACE polymorphisms were not related to the risk of COPD (p > 0.05 in each model). In further analyses based on ethnicity, we observed an association between insertion/deletion polymorphism of the ACE gene and risk of COPD in the Asian population (codominant 2, OR = 3.126, 95% CI = 1.919–5.093, p < 0.001; recessive, OR = 3.326, 95% CI = 2.190–5.050, p < 0.001) but not in the Caucasian population (p > 0.05 in each model). In conclusion, the present meta-analysis indicated that the insertion/deletion polymorphism of the ACE gene may be associated with susceptibility to COPD in the Asian population but not in the Caucasian population. However, the results of the present meta-analysis need to be confirmed in a larger sample. PMID:27830153

Rapid conversion of angiotensin I to angiotensin II by neutrophil and mast cell proteinases.

PubMed

Reilly, C F; Tewksbury, D A; Schechter, N M; Travis, J

1982-08-10

Human neutrophil cathepsin G and human skin mast cell chymase rapidly convert angiotensin I to angiotensin II with only minor cleavage elsewhere in the molecule. The rate of cleavage is consistent with a potential role for either or both of these enzymes in an alternate pathway for angiotensin II synthesis. Since neither enzyme in inhibited by captopril, an angiotensin converting enzyme inactivator, it is possible that leukocyte and mast cell enzymes may play a significant role in the development of abnormally high local concentrations of angiotensin II, associated with various inflammatory processes.

AID-initiated purposeful mutations in immunoglobulin genes.

PubMed

Goodman, Myron F; Scharff, Matthew D; Romesberg, Floyd E

2007-01-01

Exposure brings risk to all living organisms. Using a remarkably effective strategy, higher vertebrates mitigate risk by mounting a complex and sophisticated immune response to counter the potentially toxic invasion by a virtually limitless army of chemical and biological antagonists. Mutations are almost always deleterious, but in the case of antibody diversification there are mutations occurring at hugely elevated rates within the variable (V) and switch regions (SR) of the immunoglobulin (Ig) genes that are responsible for binding to and neutralizing foreign antigens throughout the body. These mutations are truly purposeful. This chapter is centered on activation-induced cytidine deaminase (AID). AID is required for initiating somatic hypermutation (SHM) in the V regions and class switch recombination (CSR) in the SR portions of Ig genes. By converting C --> U, while transcription takes place, AID instigates a cascade of mutational events involving error-prone DNA polymerases, base excision and mismatch repair enzymes, and recombination pathways. Together, these processes culminate in highly mutated antibody genes and the B cells expressing antibodies that have achieved optimal antigenic binding undergo positive selection in germinal centers. We will discuss the biological role of AID in this complex process, primarily in terms of its biochemical properties in relation to SHM in vivo. The chapter also discusses recent advances in experimental methods to characterize antibody dynamics as a function of SHM to help elucidate the role that the AID-induced mutations play in tailoring molecular recognition. The emerging experimental techniques help to address long-standing conundrums concerning evolution-imposed constraints on antibody structure and function.

Presence of angiotensin converting enzyme isoforms in larval lepidoptera (Spodoptera littoralis).

PubMed

Lemeire, E; Van Camp, J; Smagghe, G

2007-01-01

In this research the presence of angiotensin converting enzyme (ACE) in larvae of the lepidopteran Spodoptera littoralis was evaluated. Making use of the substrate Abz-FRK-(Dnp)P-OH and the specific inhibitor captopril at 10 microM, ACE activity was determined in a fluorescence assay for intact larvae, hemolymph, head, midgut and dorsal tissue. In dorsal tissue and hemolymph, ACE activity was highest. These data are consistent with a possible role for ACE in contractions of the dorsal vessel and metabolism of circulating peptide hormones in the hemolymph. After the presence of ACE was confirmed, a sequential procedure of anion exchange and size exclusion chromatography was applied to purify ACE from whole wandering larvae (last stage). With this procedure, three different ACE pools were collected that cleaved the fluorogenic substrate Abz-FRK-(Dnp)P-OH. Activity could be inhibited by a final concentration of 2.5 microM captopril. In addition, two out of three samples eluted at different salt concentration and thus ACE 1, 2 and 3 represent at least two different ACE isoforms. These data reveal that ACE is present in S. littoralis and that at least two out of three isolated ACE forms are truly isoforms.

Renin angiotensin system blockage associates with insertion/deletion polymorphism of angiotensin-converting enzyme in patients with hypertensive emergency.

PubMed

Vilela-Martin, José F; Vaz-de-Melo, Renan O; Cosenso-Martin, Luciana N; Kuniyoshi, Cristina H; Yugar-Toledo, Juan C; Pinhel, Marcela A S; de Souza, Gisele F; Souza, Dorotéia R S; Pimenta, Eduardo; Moreno, Heitor; Cipullo, José P

2013-09-01

Hypertensive crisis (HC) stands out as a form of acute elevation of blood pressure (BP). It can manifest itself as hypertensive emergency (HE) or hypertensive urgency (HU), which is usually accompanied with levels of diastolic BP ≥120 mmHg. Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism may influence manifestations of HC. Thus, this study evaluated the influence of ACE I/D polymorphism in individuals with HC. A total of 187 patients admitted with HC (HU [n=69] and HE [n=118]) and 75 normotensive individuals were included in the study. Peripheral blood was drawn for a biochemical and genetic analysis of the ACE I/D polymorphism by Polymerase Chain Reaction. HC group showed higher systolic BP, body mass index (BMI), glycemia, creatinine, and lower high-density lipoprotein (HDL) cholesterol compared with normotensive individuals. The use of renin-angiotensin system (RAS) blockers was more frequent in the HU group than in the HE group (p=0.020). The II genotype was more predominant in normotensive and HU individuals than among HE individuals (18.7%, 11.6%, and 2.5%, respectively; p=0.004). Higher BMI and glycemia were associated with HC in the logistic regression model. ACE II genotype (odds ratio [OR] 0.14; 95% confidence interval [CI] 0.04-0.51) and HDL cholesterol were protective for the development of HE. ACE II genotype was present in the HU group, compared with the HE group (OR 0.18; 95% CI 0.04-0.88). This study shows an association between the low prevalence of ACE I/D polymorphism II genotype and a greater occurrence of HE in Brazilian individuals. The lower blockage of RAS, which was detected in the HE group, may interact with the low frequency of II genotype, conferring an increased risk for HE.

Cellobiohydrolase I enzymes

DOEpatents

Adney, William S; Himmel, Michael E; Decker, Stephen R; Knoshaug, Eric P; Nimlos, Mark R; Crowley, Michael F; Jeoh, Tina

2014-01-28

Provided herein is an isolated Cel7A polypeptide comprising mutations in the catalytic domain of the polypeptide relative to the catalytic domain of a wild type Cel7A polypeptide, wherein the mutations reduce N-linked glycosylation of the isolated polypeptide relative to the wild type polypeptide. Also provided herein is an isolated Cel7A polypeptide comprising increased O-linked glycosylation of the linker domain relative to a linker domain of a wild type Cel7A polypeptide. The increased O-linked glycosylation is a result of the addition of and/or substitution of one or more serine and/or threonine residues to the linker domain relative to the linker domain of the wild type polypeptide. In some embodiments, the isolated Cel7A polypeptide comprising mutations in the catalytic domain of the polypeptide relative to the catalytic domain of a wild type Cel7A polypeptide further comprises increased O-linked glycosylation of the linker domain relative to a linker domain of a wild type Cel7A polypeptide. The mutations in the catalytic domain reduce N-linked glycosylation of the isolated polypeptide relative to the wild type polypeptide. The addition of and/or substitution of one or more serine and/or threonine residues to the linker domain relative to the linker domain of the wild type polypeptide increases O-linked glycosylation of the isolated polypeptide. Further provided are compositions comprising such polypeptides and nucleic acids encoding such polypeptides. Still further provided are methods for making such polypeptides.

The HIV-1 protease resistance mutation I50L is associated with resistance to atazanavir and susceptibility to other protease inhibitors in multiple mutational contexts.

PubMed

Sista, P; Wasikowski, B; Lecocq, P; Pattery, T; Bacheler, L

2008-08-01

The HIV-1 protease mutation I50 L causes atazanavir resistance but increases susceptibility to other PIs. Predicted phenotypic FC values were obtained from viral genotypes, using the virtual Phenotype-LM bioinformatics tool (powering vircoTYPE). To evaluate I50 L's effect on susceptibility to 8 PIs, in a large genotype database. I50 L containing routine clinical isolate samples in Virco's genotype database were paired with samples having like patterns (or profiles) of IAS-USA-defined primary PI mutations, but lacking I50 L. Using vircoTYPE (version 4.1), the median predicted FC for each mutational profile was determined. I50 L-associated shifts in FC were evaluated using drug-specific CCOs. We selected 307 and 37098 samples with and without I50 L. These corresponded to 31 mutation patterns of > or =3 samples each. I50 L caused resistance to atazanavir in all 31 mutation contexts, but was associated with higher susceptibility for other PIs. The largest I50 L-associated shifts in median predicted FC were: 1.2 to 42.4 (atazanavir), 10.2 to 3.2 (amprenavir), 3.3 to 0.5 (darunavir), 13 to 0.5 (indinavir), 34.9 to 1.3 (lopinavir), 22.3 to 1.3 (nelfinavir), 5.2 to 0.3 (saquinavir) and 29.9 to 5.2 (tipranavir). The PI mutation I50 L causes clinically relevant resistance and increased susceptibility to atazanavir and other PIs respectively.

Association of insertion/deletion polymorphism of angiotensin-converting enzyme gene among Malay male hypertensive subjects in response to ACE inhibitors.

PubMed

Heidari, Farzad; Vasudevan, Ramachandran; Mohd Ali, Siti Zubaidah; Ismail, Patimah; Etemad, Ali; Pishva, Seyyed Reza; Othman, Fauziah; Abu Bakar, Suhaili

2015-12-01

Several studies show that the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been associated with hypertension in various populations. The present study sought to determine the association of the I/D gene polymorphism among Malay male essential hypertensive subjects in response to ACE inhibitors (enalapril and lisinopril). A total of 72 patients with newly diagnosed hypertension and 72 healthy subjects were recruited in this study. Blood pressure was recorded from 0 to 24 weeks of treatment with enalapril or lisinopril. Genotyping of the I/D polymorphism was carried out using a standard PCR method. Statistically significant association of the D allele of the ACE gene was observed between the case and control subjects (p < 0.01). There was a decrease in blood pressure in the patients carrying the DD genotype (SBP=18.5±8.1 mmHg, DBP=15.29±7.1 mmHg) rather than the ID (SBP=4.1±3.3 mmHg, DBP=9.1±3.5 mmHg) and II genotypes (SBP= 3.0±0.2 mmHg, DBP 0.11±6.1 mmHg) of the ACE gene. Patients carrying the DD genotype had higher blood pressure-lowering response when treated with ACE inhibitors enalapril or lisinopril than those carrying ID and II genotypes, suggesting that the D allele may be a possible genetic marker for essential hypertension among Malay male subjects. © The Author(s) 2014.

Circulating angiotensin-converting enzyme 2 activity in kidney transplantation: a longitudinal pilot study.

PubMed

Soler, María José; Riera, Marta; Crespo, Marta; Mir, Marisa; Márquez, Eva; Pascual, María José; Puig, Josep M; Pascual, Julio

2012-01-01

Angiotensin-converting enzyme 2 (ACE2) is the only known active homologue of ACE, and degrades angiotensin (Ang) II and Ang I to Ang(1-7) and Ang(1-9), respectively. The role of ACE2 in kidney transplant (KT) is unknown. Our objective was to investigate circulating ACE2 activity in KT patients, and the relationship between serum ACE2 activity and age, gender, graft function and cardiovascular risk markers in KT patients. 113 KT patients with stable graft function were included in this cross-sectional study. Circulating ACE2 activity was assessed using a fluorescent assay. Circulating ACE2 activity was detectable in KT patients and was increased in KT with ischemic heart disease as compared to KT without ischemic heart disease (105.9 ± 8.7 vs. 97.1 ± 7.05 relative fluorescence units (RFU)/µl/h, p < 0.05). ACE2 activity was increased in male KT as compared to females (105.2 ± 9.1 vs. 84.7 ± 6.9 RFU/µl/h, p = 0.05). ACE2 activity correlated positively with serum creatinine (r = 0.27), serum urea (r = 0.29), age (r = 0.24), aspartate transaminase (r = 0.39), alanine transaminase (r = 0.48), γ-glutamyl transferase (γ-GT) (r = 0.52), age (r = 0.24), and glycosylated hemoglobin (r = 0.19) (p < 0.05). By multiple regression analysis, age, serum creatinine, and serum γ-GT were independent predictors of serum ACE2 activity (r = 0.66, p < 0.001). Circulating ACE2 activity is measurable in KT patients and directly correlates with age, renal allograft and liver function parameters. These findings suggest that measurement of serum ACE2 may be used as a non-invasive marker to understand the role of the renin-angiotensin system in KT patients. Copyright © 2012 S. Karger AG, Basel.

Saccharomyces boulardii CNCM I-745 Improves Intestinal Enzyme Function: A Trophic Effects Review

PubMed Central

Moré, Margret I; Vandenplas, Yvan

2018-01-01

Several properties of the probiotic medicinal yeast Saccharomyces boulardii CNCM I-745 contribute to its efficacy to prevent or treat diarrhoea. Besides immunologic effects, pathogen-binding and anti-toxin effects, as well as positive effects on the microbiota, S boulardii CNCM I-745 also has pronounced effects on digestive enzymes of the brush border membrane, known as trophic effects. The latter are the focus of this review. Literature has been reviewed after searching Medline and PMC databases. All relevant non-clinical and clinical studies are summarized. S. boulardii CNCM I-745 synthesizes and secretes polyamines, which have a role in cell proliferation and differentiation. The administration of polyamines or S. boulardii CNCM I-745 enhances the expression of intestinal digestive enzymes as well as nutrient uptake transporters. The signalling mechanisms leading to enzyme activation are not fully understood. However, polyamines have direct nucleic acid–binding capacity with regulatory impact. S. boulardii CNCM I-745 induces signalling via the mitogen-activated protein kinase pathway. In addition, effects on the phosphatidylinositol-3 kinase (PI3K) pathway have been reported. As an additional direct effect, S. boulardii CNCM I-745 secretes certain enzymes, which enhance nutrient acquisition for the yeast and the host. The increased availability of digestive enzymes seems to be one of the mechanisms by which S. boulardii CNCM I-745 counteracts diarrhoea; however, also people with certain enzyme deficiencies may profit from its administration. More studies are needed to fully understand the mechanisms of trophic activation by the probiotic yeast. PMID:29449779

Saccharomyces boulardii CNCM I-745 Improves Intestinal Enzyme Function: A Trophic Effects Review.

PubMed

Moré, Margret I; Vandenplas, Yvan

2018-01-01

Several properties of the probiotic medicinal yeast Saccharomyces boulardii CNCM I-745 contribute to its efficacy to prevent or treat diarrhoea. Besides immunologic effects, pathogen-binding and anti-toxin effects, as well as positive effects on the microbiota, S boulardii CNCM I-745 also has pronounced effects on digestive enzymes of the brush border membrane, known as trophic effects. The latter are the focus of this review. Literature has been reviewed after searching Medline and PMC databases. All relevant non-clinical and clinical studies are summarized. S. boulardii CNCM I-745 synthesizes and secretes polyamines, which have a role in cell proliferation and differentiation. The administration of polyamines or S. boulardii CNCM I-745 enhances the expression of intestinal digestive enzymes as well as nutrient uptake transporters. The signalling mechanisms leading to enzyme activation are not fully understood. However, polyamines have direct nucleic acid-binding capacity with regulatory impact. S. boulardii CNCM I-745 induces signalling via the mitogen-activated protein kinase pathway. In addition, effects on the phosphatidylinositol-3 kinase (PI3K) pathway have been reported. As an additional direct effect, S. boulardii CNCM I-745 secretes certain enzymes, which enhance nutrient acquisition for the yeast and the host. The increased availability of digestive enzymes seems to be one of the mechanisms by which S. boulardii CNCM I-745 counteracts diarrhoea; however, also people with certain enzyme deficiencies may profit from its administration. More studies are needed to fully understand the mechanisms of trophic activation by the probiotic yeast.

Relative lipophilicities and structural-pharmacological considerations of various angiotensin-converting enzyme (ACE) inhibitors.

PubMed

Ranadive, S A; Chen, A X; Serajuddin, A T

1992-11-01

Lipophilicities of seven structurally diverse angiotensin-converting enzyme (ACE) inhibitors, viz., captopril, zofenoprilat, enalaprilat, ramiprilat, lisinopril, fosinoprilat, and ceronapril (SQ29852), were compared by determining their octanol-water distribution coefficients (D) under physiological pH conditions. The distribution co-efficients of zofenopril, enalapril, ramipril and fosinopril, which are the prodrug forms of zofenoprilat, enalaprilat, ramiprilat, and fosinoprilat, respectively, were also determined. Attempts were made to correlate lipophilicities with the reported data for oral absorption, protein binding, ACE inhibitory activity, propensity for biliary excretion, and penetration across the blood-brain barrier for these therapeutic entities. Better absorption of prodrugs compared to their respective active forms is in agreement with their greater lipophilicities. Captopril, lisinopril, and ceronapril are orally well absorbed despite their low lipophilicities, suggesting involvement of other factors such as a carrier-mediated transport process. Of all the compounds studied, the two most lipophilic ACE inhibitors, fosinoprilat and zofenoprilat, exhibit a rank-order correlation with respect to biliary excretion. This may explain the dual routes of elimination (renal and hepatic) observed with fosinoprilat in humans. The more lipophilic compounds also exhibit higher protein binding. Both the lipophilicity and a carrier-mediated process may be involved in penetration of some of these drugs into brain. For structurally similar compounds, in vitro ACE inhibitory activity increased with the increase in lipophilicity. However, no clear correlation between lipophilicity and ACE inhibitory activity emerged when different types of inhibitors are compared, possibly because their interactions with enzymes are primarily ionic in nature.

Mutations in mitochondrial enzyme GPT2 cause metabolic dysfunction and neurological disease with developmental and progressive features

PubMed Central

Ouyang, Qing; Nakayama, Tojo; Baytas, Ozan; Davidson, Shawn M.; Yang, Chendong; Schmidt, Michael; Lizarraga, Sofia B.; Mishra, Sasmita; EI-Quessny, Malak; Niaz, Saima; Gul Butt, Mirrat; Imran Murtaza, Syed; Javed, Afzal; Chaudhry, Haroon Rashid; Vaughan, Dylan J.; Hill, R. Sean; Partlow, Jennifer N.; Yoo, Seung-Yun; Lam, Anh-Thu N.; Nasir, Ramzi; Al-Saffar, Muna; Barkovich, A. James; Schwede, Matthew; Nagpal, Shailender; Rajab, Anna; DeBerardinis, Ralph J.; Housman, David E.; Mochida, Ganeshwaran H.; Morrow, Eric M.

2016-01-01

Mutations that cause neurological phenotypes are highly informative with regard to mechanisms governing human brain function and disease. We report autosomal recessive mutations in the enzyme glutamate pyruvate transaminase 2 (GPT2) in large kindreds initially ascertained for intellectual and developmental disability (IDD). GPT2 [also known as alanine transaminase 2 (ALT2)] is one of two related transaminases that catalyze the reversible addition of an amino group from glutamate to pyruvate, yielding alanine and α-ketoglutarate. In addition to IDD, all affected individuals show postnatal microcephaly and ∼80% of those followed over time show progressive motor symptoms, a spastic paraplegia. Homozygous nonsense p.Arg404* and missense p.Pro272Leu mutations are shown biochemically to be loss of function. The GPT2 gene demonstrates increasing expression in brain in the early postnatal period, and GPT2 protein localizes to mitochondria. Akin to the human phenotype, Gpt2-null mice exhibit reduced brain growth. Through metabolomics and direct isotope tracing experiments, we find a number of metabolic abnormalities associated with loss of Gpt2. These include defects in amino acid metabolism such as low alanine levels and elevated essential amino acids. Also, we find defects in anaplerosis, the metabolic process involved in replenishing TCA cycle intermediates. Finally, mutant brains demonstrate misregulated metabolites in pathways implicated in neuroprotective mechanisms previously associated with neurodegenerative disorders. Overall, our data reveal an important role for the GPT2 enzyme in mitochondrial metabolism with relevance to developmental as well as potentially to neurodegenerative mechanisms. PMID:27601654

Antioxidation, angiotensin converting enzyme inhibition activity, nattokinase, and antihypertension of Bacillus subtilis (natto)-fermented pigeon pea.

PubMed

Lee, Bao-Hong; Lai, Yi-Syuan; Wu, She-Ching

2015-12-01