Tags: Protein.
GTP cyclohydrolase I (GTPCH) (EC 3.5.4.16) is a member of the GTP cyclohydrolase family of enzymes. GTPCH is part of the folate and biopterin biosynthesis pathways. It is responsible for the hydrolysis of guanosine triphosphate (GTP) to form 78-dihydroneopterin triphosphate (78-DHNP-3′-TP 78-NH2-3′-TP).