ASMT is a member of the methyltransferase superfamily. ASMT participates in melatonin biosynthesis. ASMT Expressed in brain, retina and pineal gland, ASMT utilities to catalyze the final reaction in the synthesis of melatonin, particularly the conversion of S-adenosyl-L-methionine and N-acetylserotonin to S-adenosyl-Lhomocysteine and melatonin.