Relationship between Genetic Polymorphism of Arsenic(+3 oxidation state) Methyltransferase(AS3MT)and Profile of Urinary Arsenic Compounds in Vietnamese

Abstract

We investigated genetic polymorphism of 287Met>Thr(Met-to-Thr substitution at amino acid base 287)in arsenic(+3 oxidation state)methyltransferase(AS3MT),which is an S-adenosyl-L-methionine-dependent enzyme that catalyzes the methylation of arsenite(As^III)and methylated As, and its relation to urinary arsenic profile in 100 individuals from the Red River Delta, Vietnam. Allele mutation frequency(2%)in this population was similar to that in other Asian populations, but relatively lower than those in Caucasians and Africans. Dimethylarsinic acid was the predominant compound in urine, followed by arsenobetaine. Low levels of inorganic arsenic(IA)and monomethylarsonic acid(MMA)were also detected. Concentration ratio of urinary MMA/IA for TC heterozygote was significantly higher than that for TT homozygote, suggesting higher methylation capacity from IA to MMA in individuals with TC.