Enzymology and toxicity of inorganic arsenic

Publisher Summary The biotransformation of inorganic arsenate to dimethylarsinic acid (DMA) involves a series of enzymatic steps. Recent studies based on amino acid homology and other properties demonstrate that the human liver arsenate reductase and the human purine nucleoside phosphorylase (PNP) are identical proteins. The reaction requires inosine and dihydrolipoic acid. Dihydrolipoic acid is the most potent naturally occurring dithiol in this reaction. PNP is an essential enzyme involved in purine and nucleic acid metabolism. Arsenate reductase/PNP will not reduce monomethylarsonous acid (MMA V ).