GSTO1 is a member of the theta class glutathione Stransferase-like (GSTTL) protein family. GSTO1 is expressed in a wide range of human tissues and exhibits glutathione-dependent thiol transferase and dehydroascorbate reductase activities and also catalyzes the reduction of monomethylarsonate, an intermediate in the pathway of arsenic biotransformation. GSTO1 protects from oxidative stress, a risk factor for Alzheimer disease, vascular dementia and stroke. Several polymorphisms in the coding regions of the human GSTO1 have been identified. A polymorphism causing an alanine-toaspartate (A140D) substitution in amino acid 140 produces a variant with lowered enzyme activities in the arsenic biotransformation.
