The metabolism of methylarsine oxide and sulfide

Abstract

Abstract Methylarsine oxide and sulfide are more toxic to Candida humicola than arsenite; the sulfide is rapidly metabolized to trimethylarsine (Me 3 As) and methylarsine (MeAsH 2 ) and the oxide to dimethylarsinic acid [Me 2 AsO(OH)]. Cell‐free extracts of C. humicola also convert the oxide to Me 2 AsO(OH). The glutathione (RSH) derivative Me 2 AsSR is metabolized by C. humicola to Me 3 As and Me 2 AsH, but some other Me 2 AsSR′ compounds are unaffected. Studies involving the interaction of the arsenic(III) compounds with natural ecosystems and other micro‐organisms such as Scopulariopsis brevicaulis , Straptococcus sanguis , Escherichia coli , and Veillonella alcalescens are described.