Precursor to metabolite: Tryptophan to 5-hydroxytryptophan

Tryptophan is converted to 5-hydroxytryptophan by tryptophan hydroxylase.

Tryptophan mascot — mnemonic cartoon — Visual mnemonic: Tryptophan mascot

The pair

Tryptophan — Dietary serotonin precursor; sleep/mood supplement.
5-hydroxytryptophan — Serotonin precursor (5-HTP); OTC supplement, no receptor action of its own.

Tryptophan · 5-hydroxytryptophan · Open Tryptophan in the interactive console ↗