ScienceDirect Publication: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Melatonin (Mel) synthesis in flounder skin involves an alternative pathway, not the classic one. The enzyme N-acetylserotonin O-methyltransferase like (ASMTL) methylates serotonin (5-HT) to 5-methoxytryptamine (5-MT), which is then acetylated by N-acetyltransferase (NAT) to Mel. This pathway is suggested by the presence of ASMTL and NAT activities in flounder skin homogenates. The classic pathway, involving the conversion of serotonin to N-acetylserotonin (NAS) and then to Mel, is not effective in Mel synthesis in flounder skin. This study provides new insights into Mel synthesis in vertebrates.