scholarly journals Functional characterization of the chlorzoxazone 6-hydroxylation activity of human cytochrome P450 2E1 allelic variants in Han Chinese

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9628
Author(s):  
Ting Wang ◽  
Huihui Du ◽  
Jingsong Ma ◽  
Lu Shen ◽  
Muyun Wei ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cytochrome P450 ◽  
Genetic Polymorphisms ◽  
Han Chinese ◽  
Enzyme Function ◽  
Wild Type ◽  
Coding Region ◽  
Allelic Variants ◽  
Hydroxylation Activity

Backgrounds Cytochrome P450 (P450) 2E1 is one of the primary enzymes responsible for the metabolism of xenobiotics, such as drugs and environmental carcinogens. The genetic polymorphisms of the CYP2E1 gene in promoter and coding regions have been identified previously in the Han Chinese population from four different geographic areas of Mainland China. Methods To investigate whether genetic variants identified in the CYP2E1 coding region affect enzyme function, the enzymes of four single nucleotide polymorphism (SNP) variants in the coding region (novel c.1009C>T, causing p.Arg337X, where X represents the translational stop codon; c.227G>A, causing p.Arg76His; c.517G>A, yielding p.Gly173Ser; and c.1263C>T, presenting the highest allele frequency), two novel alleles (c.[227G>A;1263C>T] and c.[517G>A;1263C>T]), and the wild-type CYP2E1 were heterologously expressed in COS-7 cells and functionally characterized in terms of expression level and chlorzoxazone 6-hydroxylation activity. The impact of the CYP2E1 variant sequence on enzyme activity was predicted with three programs: Polyphen 2, PROVEAN and SIFT. Results The prematurely terminated p.Arg337X variant enzyme was undetectable by western blotting and inactive toward chlorzoxazone 6-hydroxylation. The c.1263C>T and c.[517G>A;1263C>T] variant enzymes exhibited properties similar to those of the wild-type CYP2E1. The CYP2E1 variants c.227G>A and c.[227G>A;1263C>T] displayed significantly reduced enzyme activity relative to that of the wild-type enzyme (decreased by 42.8% and 32.8%, respectively; P < 0.01). The chlorzoxazone 6-hydroxylation activity of the c.517G>A transfectant was increased by 31% compared with the wild-type CYP2E1 enzyme (P < 0.01). Positive correlations were observed between the protein content and enzyme activity for CYP2E1 (P = 0.0005, r2 = 0.8833). The characterization of enzyme function allelic variants in vitro was consistent with the potentially deleterious effect of the amino acid changes as determined by prediction tools. Conclusions These findings indicate that the genetic polymorphisms of CYP2E1, i.e., c.1009C>T (p.Arg337X), c.227G>A (p.Arg76His), and c.517G>A (p.Gly173Ser), could influence the metabolism of CYP2E1 substrates, such as chlorzoxazone.

Functional Characterization of Wild-type and 49 CYP2D6 Allelic Variants for N-Desmethyltamoxifen 4-Hydroxylation Activity

2014 ◽  
Vol 29 (5) ◽  
pp. 360-366 ◽  
Author(s):  
Yuka Muroi ◽  
Takahiro Saito ◽  
Masamitsu Takahashi ◽  
Kanako Sakuyama ◽  
Yui Niinuma ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Wild Type ◽  
Allelic Variants ◽  
Hydroxylation Activity

scholarly journals Distributive characteristics of the CYP2C9 and AGTR1 genetic polymorphisms in Han Chinese hypertensive patients: a retrospective study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Keping Chen ◽  
Peng Xiao ◽  
Guochun Li ◽  
Chunling Wang ◽  
Chuankun Yang
Keyword(s):  
Genetic Polymorphisms ◽  
Venous Blood ◽  
Gene Chip ◽  
Han Chinese ◽  
Genotype Frequency ◽  
Wild Type ◽  
Angiotensin Ii Receptor ◽  
Hypertensive Patients ◽  
Genotype Frequencies ◽  
Combined Genotypes

Abstract Background There is an individual variation in response to antihypertensive effect of the angiotensin II receptor antagonist. This study aimed to determine the allele and genotype frequencies of CYP2C9 and AGTR1 genetic polymorphisms and explore the potential role of these polymorphisms in guiding the selection of angiotensinIIreceptor antagonist in Han Chinese hypertensive patients. Methods Totally 2419 Han Chinese hypertensive patients and 126 normotensive controls were recruited in this study. Venous blood samples were collected from each patient, and the genetic polymorphisms of CYP2C9 and AGTR1 were assessed using a gene chip platform. The allele and genotype frequency of each gene and the combined genotypes in this study were analyzed respectively. Results The gene chip analysis identified an allelic frequency of 96.51% for CYP2C9*1 and 3.49% for CYP2C9*3 in the cohort of Han Chinese hypertensive patients. Statistical analysis showed that the frequency of wild-type homozygous for CYP2C9*1/*1 was 93.30%, while the frequency of heterozygous for *1/*3 or mutant homozygous for *3/*3 was 6.41% or 0.29%. Meanwhile, we detected allelic frequencies of 95.06% and 4.94% for the A and C allele of AGTR1, respectively. While the genotype frequency of wild-type homozygous for AA was 90.41%, the frequency of heterozygous for AC or mutant homozygous for CC was 9.30% or 0.29%. Notably, we observed that 84.66% (2048/2419) of the subjects exhibited a combined genotype of CYP2C9 and AGTR1 as *1/*1 + AA, while the combined genotypes *3/*3 + AC or *3/*3 + CC were not detected in hypertension patients. Besides, no significant association was found between normotensive controls and hypertensive patients, or among the three grades of hypertensive patients. Conclusions These data revealed the polymorphisms characteristics of CYP2C9 and AGTR1 in Han Chinese hypertensive patients, providing valuable information for genotype-based antihypertension therapy in prospective clinical studies in the future.

Genetic polymorphisms of cytochrome P450 2B6 gene in Han Chinese

2006 ◽  
Vol 29 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Su Guan ◽  
Min Huang ◽  
Eli Chan ◽  
Xiao Chen ◽  
Wei Duan ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Genetic Polymorphisms ◽  
Han Chinese ◽  
Cytochrome P450 2B6

Influence of genetic polymorphisms in cytochrome P450 oxidoreductase on the variability in stable warfarin maintenance dose in Han Chinese

2016 ◽  
Vol 72 (11) ◽  
pp. 1327-1334 ◽  
Author(s):  
Wu-Tao Zeng ◽  
Qing Xu ◽  
Cheng-Hsun Li ◽  
Wei-Yan Chen ◽  
Xiu-Ting Sun ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Genetic Polymorphisms ◽  
Maintenance Dose ◽  
Han Chinese ◽  
P450 Oxidoreductase ◽  
Cytochrome P450 Oxidoreductase ◽  
Warfarin Maintenance Dose

scholarly journals Characterization of Medicago truncatula (barrel medic) hydroperoxide lyase (CYP74C3), a water-soluble detergent-free cytochrome P450 monomer whose biological activity is defined by monomer–micelle association

2006 ◽  
Vol 395 (3) ◽  
pp. 641-652 ◽  
Author(s):  
Richard K. Hughes ◽  
Eric J. Belfield ◽  
Mylrajan Muthusamay ◽  
Anuja Khan ◽  
Arthur Rowe ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cytochrome P450 ◽  
Medicago Truncatula ◽  
Water Soluble ◽  
Hydroperoxide Lyase ◽  
Cytochrome P450 Enzyme ◽  
Cytochrome P450 Enzymes ◽  
P450 Enzyme ◽  
Detergent Micelles

We describe the detailed biochemical characterization of CYP74C3 (cytochrome P450 subfamily 74C3), a recombinant plant cytochrome P450 enzyme with HPL (hydroperoxide lyase) activity from Medicago truncatula (barrel medic). Steady-state kinetic parameters, substrate and product specificities, RZ (Reinheitszahl or purity index), molar absorption coefficient, haem content, and new ligands for an HPL are reported. We show on the basis of gel filtration, sedimentation velocity (sedimentation coefficient distribution) and sedimentation equilibrium (molecular mass) analyses that CYP74C3 has low enzyme activity as a detergent-free, water-soluble, monomer. The enzyme activity can be completely restored by re-activation with detergent micelles, but not detergent monomers. Corresponding changes in the spin state equilibrium, and probably co-ordination of the haem iron, are novel for cytochrome P450 enzymes and suggest that detergent micelles have a subtle effect on protein conformation, rather than substrate presentation, which is sufficient to improve substrate binding and catalytic-centre activity by an order of magnitude. The kcat/Km of up to 1.6×108 M−1·s−1 is among the highest recorded, which is remarkable for an enzyme whose reaction mechanism involves the scission of a C–C bond. We carried out both kinetic and biophysical studies to demonstrate that this effect is a result of the formation of a complex between a protein monomer and a single detergent micelle. Association with a detergent micelle rather than oligomeric state represents a new mechanism of activation for membrane-associated cytochrome P450 enzymes. Highly concentrated and monodispersed samples of detergent-free CYP74C3 protein may be well suited for the purposes of crystallization and structural resolution of the first plant cytochrome P450 enzyme.

Functional characterization of genetic polymorphisms identified in the human cytochrome P450 4F12 (CYP4F12) promoter region

2004 ◽  
Vol 67 (12) ◽  
pp. 2231-2238 ◽  
Author(s):  
Christelle Cauffiez ◽  
Florian Klinzig ◽  
Emmanuel Rat ◽  
Gilles Tournel ◽  
Delphine Allorge ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Genetic Polymorphisms ◽  
Promoter Region ◽  
Functional Characterization ◽  
Human Cytochrome

scholarly journals Functional Characterization of Allelic Variants of Polymorphic Human Cytochrome P450 2A6 (CYP2A6*5, *7, *8, *18, *19, and *35)

2012 ◽  
Vol 35 (3) ◽  
pp. 394-399 ◽  
Author(s):  
Songhee Han ◽  
Seunghye Choi ◽  
Young-Jin Chun ◽  
Chul-Ho Yun ◽  
Chang Hoon Lee ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Functional Characterization ◽  
Allelic Variants ◽  
Human Cytochrome ◽  
Cytochrome P450 2A6

Genetic finding and functional characterization of cytochrome P450 4F11 genetic polymorphisms in a Korean population

2017 ◽  
Vol 32 (1) ◽  
pp. S87-S88
Author(s):  
Myeongjin Yi ◽  
Sung Eun Yoo ◽  
Sun-Ah Cho ◽  
Dong-Hyun Kim ◽  
Jae-Gook Shin ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Genetic Polymorphisms ◽  
Functional Characterization ◽  
Korean Population ◽  
Genetic Finding

scholarly journals Characterization of glutamine synthetase from the ammonium-excreting strain HM053 of Azospirillum brasilense

2022 ◽  
Vol 82 ◽  
Author(s):  
Fernanda Ghenov ◽  
Edileusa Cristina Marques Gerhardt ◽  
Luciano Fernandes Huergo ◽  
Fabio Oliveira Pedrosa ◽  
Roseli Wassem ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Glutamine Synthetase ◽  
Affinity Chromatography ◽  
Azospirillum Brasilense ◽  
Nitrogen Assimilation ◽  
Atp Hydrolysis ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
E Coli

Abstract Glutamine synthetase (GS), encoded by glnA, catalyzes the conversion of L-glutamate and ammonium to L-glutamine. This ATP hydrolysis driven process is the main nitrogen assimilation pathway in the nitrogen-fixing bacterium Azospirillum brasilense. The A. brasilense strain HM053 has poor GS activity and leaks ammonium into the medium under nitrogen fixing conditions. In this work, the glnA genes of the wild type and HM053 strains were cloned into pET28a, sequenced and overexpressed in E. coli. The GS enzyme was purified by affinity chromatography and characterized. The GS of HM053 strain carries a P347L substitution, which results in low enzyme activity and rendered the enzyme insensitive to adenylylation by the adenilyltransferase GlnE.

scholarly journals Sequence Characterization of theMC1RGene in Yak (Poephagus grunniens) Breeds with Different Coat Colors

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Shi-Yi Chen ◽  
Yi Huang ◽  
Qing Zhu ◽  
Luca Fontanesi ◽  
Yong-Gang Yao ◽  
...  
Keyword(s):  
Coat Color ◽  
Extracellular Loop ◽  
Wild Type ◽  
Coding Region ◽  
Functional Effect ◽  
Nucleotide Substitutions ◽  
Melanocortin 1 Receptor ◽  
Sequence Characterization ◽  
Potential Association

Melanocortin 1 receptor (MC1R) gene plays a key role in determining coat color in several species, including the cattle. However, up to now there is no report regarding theMC1Rgene and the potential association of its mutations with coat colors in yak (Poephagus grunniens). In this study, we sequenced the encoding region of theMC1Rgene in three yak breeds with completely white (Tianzhu breed) or black coat color (Jiulong and Maiwa breeds). The predicted coding region of the yakMC1Rgene resulted of 954 bp, the same to that of the wild-type cattle sequence, with >99% identity. None of the mutation events reported in cattle was found. Comparing the yak obtained sequences, five nucleotide substitutions were detected, which defined three haplotypes (EY1,EY2, andEY3). Of the five mutations, two, characterizing theEY1haplotype, were nonsynonymous substitutions (c.340C>A and c.871G>A) causing amino acid changes located in the first extracellular loop (p.Q114K) and in the seventh transmembrane region (p.A291T).In silicoprediction might indicate a functional effect of the latter substitution. However, all three haplotypes were present in the three yak breeds with relatively consistent frequency distribution, despite of their distinguished coat colors, which suggested that there was no across-breed association between haplotypes or genotypes and black/white phenotypes, at least in the investigated breeds. Other genes may be involved in affecting coat color in the analyzed yaks.

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