Methylation of N-acetyl-5-HT to form melatonin Authored: Jassal, B, 2008-10-01 13:18:42 Edited: Jassal, B, 2008-05-28 09:06:10 Hydroxyindole-O-methyltransferase (HIOMT) catalyzes the last step in the synthesis of melatonin. Melatonin is synthesized and released by the pineal gland and is thought to control circadian rhythms. HIOMT has 3 isoforms and utilizes S-adenosyl-L-methionine (SAM) as the methyl donor in the conversion of N-acetyl-5HT to melatonin. Pubmed7989373 Reactome Database ID Release 43209821 Reactome, http://www.reactome.org ReactomeREACT_15383 Reviewed: D'Eustachio, P, 2008-05-28 08:30:54