Tetrahydrobiopterin is required for the metabolism of
THB is a cofactor for Aromatic amino acid (Tryptophan, Phenylalanine & Tyrosine) hydroxylases (See Fig)* Nitric acid synthase Serotonin synthesis Non-classical phenylketonuria types are due to defect in the synthesis or recycling of THB. Tetrahydrobiopterin (THB) is a nucleotide cofactor derived from Guanosine triphosphate.
Alanine
Lysine
Phenylalanine
Serine
Cofactor and prosthetic groups