You are here:
PATHWAY OF INORGANIC ARSENIC METABOLISM
Citation:
THOMAS, D. J. PATHWAY OF INORGANIC ARSENIC METABOLISM. Presented at U.S. EPA Workshop on Research and Risk Assessment for Arsenic, Shepherdstown, WV, May 31 - June 02, 2006.
Description:
A remarkable aspect of the metabolism of inorganic arsenic in humans is its conversion to methylated metabolites. These metabolites account for most of the arsenic found in urine after exposure to inorganic arsenic. At least some of the adverse health effects attributed to inorganic arsenic are probably mediated by methylated arsenicals. Steps in formation of methylated arsenicals from inorganic arsenic are enzymatically catalyzed. In humans, arsenic (+3 oxidation state) methyltransferase catalyzes all reactions required to convert arsenite into methylated and dimethylated species. Two conceptual models have been developed to describe function of this enzyme in the pathway that leads from inorganic arsenic to methylated products. Recent studies of a common polymorphism of arsenic (+3 oxidation state) methyltransferase provide additional insights into the role of this enzyme in methylation of inorganic arsenic. In sum, it is now possible to develop a coherent picture of the enzymatic basis of the metabolism of inorganic arsenic and to describe how metabolism is linked to actions of arsenicals as toxins and carcinogens. (This abstract does not reflect U.S. EPA policy.)