an enzyme which catalyzes the initial step in the biosynthesis of serotonin. It utilizes tetrahydrobiopterin as a component enzyme to modify the dietary amino acid i-tryptophan to 5-hydroxytryptophan. This response is the rate-restricting step in serotonin synthesis, inhibited by amounts of tryptophan within the brain in addition to by amount of activity of neurons which utilize serotonin as a neurotransmitter.

TRYPTOPHAN HYDROXYLASE: "Tryptophan hydroxylase levels are far below what the physician would like."
Cite this page: N., Pam M.S., "TRYPTOPHAN HYDROXYLASE," in, April 29, 2013, (accessed October 15, 2021).