MtaA_CmuA_like family. MtaA/CmuA, also MtsA, or methyltransferase 2 (MT2) MT2-A and MT2-M isozymes, are methylcobamide:Coenzyme M methyltransferases, which play a role in metabolic pathways of methane formation from various substrates, such as methylated amines and methanol. Coenzyme M, 2-mercaptoethylsulfonate or CoM, is methylated during methanogenesis in a reaction catalyzed by three proteins. A methyltransferase methylates the corrinoid cofactor, which is bound to a second polypeptide, a corrinoid protein. The methylated corrinoid protein then serves as a substrate for MT2-A and related enzymes, which methylate CoM.