What is "biopterin"

n. A coenzyme produced within the body, an oxidized degradation product of tetrahydrobiopterin. Defects in biopterin synthesis or regeneration can cause a form of hyperphenylalaninemia, and biopterin deficiency has been associated with dystonia and rabies.

Biopterins are pterin derivatives which function as endogenous enzyme cofactors in many species of animals and in some bacteria and fungi. Biopterins act as cofactors for aromatic amino acid hydroxylases (AAAH), which are involved in the synthesis a number of neurotransmitters including dopamine, norepinephrine, epinepherine, and serotonin, along with several trace amines; nitric oxide synthesis also utilizes biopterin derivatives as cofactors. In humans, tetrahydrobiopterin is the endogenous cofactor for AAAH enzymes.