Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Figure 1. Synthesis of melatonin in the skin. It is involved sequential transformation of tryptophan in a cascade of enzymatic reactions catalyzed by tryptophan hydroxylase (TPH1, TPH2), amino acid decarboxylase (AAD), arylalkylamine N-acetyltransferase (AANAT), arylamine N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT).
