Protein arginine methyl transferase (PRMT) family of enzymes catalyzes the methylation of arginine during post translational modification. These enzymes transfer the methyl group from S-adenosyl-L-methionine to the guanidino nitrogen atoms of an arginine residue. PRMTs are divided in two major types, I and II. Both types catalyze the formation of monomethylarginine, but differs in th at Type I (including PRMT1, 3, 4, and 6) catalyzes the formation of asymmetric dimethylarginine, whereas type II (PRMT5) catalyzes the formation of symmetric dimethylarginine. Proteins involved in the metabolism of RNA like 68-kDa Src-associated substrate in mitosis (Sam68) are substrates for PRMT1.
