GTP Cyclohydrolase I Feedback Regulator Protein (GCHFR)

GTP cyclohydrolase I feedback regulatory protein binds to and mediates tetrahydrobiopterin inhibition of GTP cyclohydrolase I. The regulatory protein, GCHFR, consists of a homodimer. It is postulated that GCHFR may play a role in regulating phenylalanine metabolism in the liver and in the production of biogenic amine neurotransmitters and nitric oxide.

Milstien et al. (1996) used peptide sequences to clone the corresponding rat cDNA which encodes an 84-amino acid polypeptide. Northern blotting of rat tissues revealed that an 0.8-kb GFRP transcript was expressed at relatively high levels in liver and kidney and at somewhat lower levels in testis, heart, brain, and lung.GFRP may play a role in regulating phenylalanine metabolism in the liver and in the production of biogenic amine neurotransmitters and nitric oxide.