Reaction: (1) S-adenosyl-L-methionine + arsenite = S-adenosyl-L-homocysteine + methylarsonate
(2) S-adenosyl-L-methionine + methylarsonite = S-adenosyl-L-homocysteine + dimethylarsinate
For diagram click here.
Other name(s): S-adenosyl-L-methionine:arsenic(III) methyltransferase; S-adenosyl-L-methionine:methylarsonite As-methyltransferase; methylarsonite methyltransferase
Systematic name: S-adenosyl-L-methionine:arsenite As-methyltransferase
Comments: An enzyme of the biotransformation pathway that forms dimethylarsinate from inorganic arsenite and arsenate. It methylates arsenite to form methylarsonate, Me-AsO3H2, which is reduced by EC 220.127.116.11, methylarsonate reductase, to methylarsonite, Me-As(OH)2. Methylarsonite is also a substrate for this enzyme (EC 18.104.22.168), which converts it into the much less toxic compound dimethylarsinate (cacodylate), Me2As(O)-OH.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, UM-BBD, CAS registry number: 167140-41-2
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