The modified amino acid, called
dihydroxyphenylalanine (DOPA), has two functions.
TH is a key enzyme and serves as the rate-limiting enzyme in DA production, as it could convert dietary tyrosine to L-
dihydroxyphenylalanine (L-DOPA), which may in turn be converted by aromatic amino acid decarboxylase (AADC) to the production of DA.
Tyr is known to be the rate-limiting enzyme affecting the production of melanin pigment [52], which oxidates tyrosine to
dihydroxyphenylalanine (DOPA) and determines which type of melanin could be synthesized [53].
It's been known for a number of years that a key ingredient of mussel glue is
dihydroxyphenylalanine (DOPA).
Catecholamines and
dihydroxyphenylalanine in metamorphosing larvae of the nudibranch Phestilla sibogae Bergh (Gastropoda: Opisthobranchia).
The bulk of the urinary dopamine may be from renal production and uptake of dopamine and decarboxylation of circulating
dihydroxyphenylalanine (dopa), [23, 24] which is in turn from hydrolysis of tyrosine.
