Biopterin

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.