In enzyme|lang=en terms the difference between methyltransferase and monomethyltransferase
is that methyltransferase is (enzyme) any enzyme that catalyzes transmethylation while monomethyltransferase is (enzyme) any methyltransferase that transfers a single methyl group.
As nouns the difference between methyltransferase and monomethyltransferase
is that methyltransferase is (enzyme) any enzyme that catalyzes transmethylation while monomethyltransferase is (enzyme) any methyltransferase that transfers a single methyl group.