GTP cyclohydrolase I feedback regulatory protein (GFRP) is encoded by the gene GCHFR. GFRP mediates feedback inhibition of GTP cyclohydrolase I activity by tetrahydrobiopterin. GFRP also acts as a mediator for the stimulatory effect of phenylalanine on enzyme activity. L-phenylalanine reverses this inhibition. The molecular weight of GFRP is approximately 9.5 kDa although cross-linking experiments have shown that GFRP is usually found as a homodimer or as a pentamer. 15q15.
Synonyms: GCHFR, GFRP, GFRP_HUMAN, GTP cyclohydrolase 1 feedback regulatory protein, GTP cyclohydrolase I feedback regulator, GTP cyclohydrolase I feedback regulatory protein, HsT16933, MGC138467, MGC138469, p35.