Anti-ASMT antibodies are used in the immunodetection of the protein acetylserotonin O-methyltransferase. In humans, the canonical protein has a reported length of 345 amino acid residues and a mass of 38.5 kDa. Alternative splicing is reported to yield 3 different isoforms for this protein. It is reported to be expressed in the pineal gland. A member of a the Cation-independent O-methyltransferase protein family, ASMT is known to catalyze the transfer of a methyl group onto N-acetylserotonin, producing melatonin (N-acetyl-5-methoxytryptamine). Synonyms for this target antigen include HIOMT, HIOMTY, acetylserotonin N-methyltransferase, acetylserotonin methyltransferase (Y chromosome), hydroxyindole O-methyltransferase, and ASMTY.