Detection and biochemical characterisation of a novel polymorphism in the human GSTP1 gene.
The glutathione transferases (GSTs) mediate the detoxification of a broad spectrum of electrophilic chemicals. We report here the identification and characterisation of a novel naturally occurring transition that changes codon 169 from GGC (Gly) to GAC (Asp) in the human Pi class GST, GSTP1. Expression of the variant in human HepG2 cells led to a small increase in 1-chloro-2,4-dinitrobenzene (CDNB) conjugation compared to the wild-type protein. Asp(169) GSTP1-1 expressed at high levels in Escherichia coli displayed a small but significant increase in specific activity towards CDNB compared to Gly(169) GSTP1-1. The catalytic efficiency with CDNB was higher for Asp(169) GSTP1-1 compared to the wild-type enzyme, although the kinetic constants of the mutant and the wild-type enzyme towards glutathione were not different. Modelling indicated that the mutation does not appear to change protein conformation. The distribution of the genotypes in a normal healthy population (217 individuals) was 94.3% for the Gly/Gly genotype and 5.7% for the Gly/Asp genotype; no Asp/Asp genotypes were detected in this population. The frequency of the Asp(169) allele in the only oxidative stress-linked pathology that we have studied to date, i.e. alcoholic liver disease, was not significantly different from healthy controls. In conclusion, we have detected and characterised a novel SNP in GSTP1 that may play a role in modulating the activity of GSTP1-1.
Kitteringham
Neil R
NR
Department of Pharmacology and Therapeutics, School of Biomedical Sciences, The University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, Merseyside, UK.
Palmer
Luke
L
Owen
Andrew
A
Lian
Lu-Yun
LY
Jenkins
Roz
R
Dowdall
Sam
S
Gilmore
Ian
I
Park
B Kevin
BK
Goldring
Chris E
CE
D000483:Alleles; D019943:Amino Acid Substitution; D001224:Aspartic Acid / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000473:pathology; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D004137:Dinitrochlorobenzene / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005787:Gene Frequency; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000145:classification / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008108:Liver Diseases, Alcoholic / Q000235:genetics / Q000473:pathology; D008113:Liver Neoplasms / Q000473:pathology; D008958:Models, Molecular; D011110:Polymorphism, Genetic; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013696:Temperature
D004137:Dinitrochlorobenzene; D011994:Recombinant Proteins; D001224:Aspartic Acid; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase