Acetylserotonin-O-Methyltransferase (ASMT)

N-Acetylserotonin O-methyltransferase is an enzyme that catalyzes the final reaction in melatonin biosynthesis, converting Normelatonin to melatonin. This reaction is embedded in the more general tryptophan metabolism pathway. The enzyme also catalyzes a second reaction in tryptophan metabolism: the conversion of 5-hydroxy-indoleacetate to 5-methoxy-indoleacetate.Acetylserotonin O-methyltransferase is an enzyme that is coded for by genes located on the PAR region of the X and Y chromosome, and is most abundantly found in the pineal gland and retina of humans. Although the exact structure of N- Acetylserotonin O-methyltransferase has yet to be determined by X-Ray diffraction, the crystal structure of the Maf domain of human N-Acetylserotonin O-methyltransferase-like protein has been found.