Arsenite methyltransferase (EC 2.1.1.137, S-adenosyl-L-methionine:arsenic(III) methyltransferase, S-adenosyl-L-methionine:methylarsonite As-methyltransferase, methylarsonite methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:arsenite As-methyltransferase. This enzyme catalyses the following chemical reaction Arsenite methyltransferase (EC 2.1.1.137, S-adenosyl-L-methionine:arsenic(III) methyltransferase, S-adenosyl-L-methionine:methylarsonite As-methyltransferase, methylarsonite methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:arsenite As-methyltransferase. This enzyme catalyses the following chemical reaction