GTP cyclohydrolase II

From Wikipedia, the free encyclopedia
Jump to: navigation, search
GTP cyclohydrolase II
EC number
CAS number 56214-35-8
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO

In enzymology, a GTP cyclohydrolase II (EC is an enzyme that catalyzes the chemical reaction

GTP + 3 H2O formate + 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine + diphosphate

Thus, the two substrates of this enzyme are GTP and H2O, whereas its 3 products are formate, 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine, and diphosphate.

This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. The systematic name of this enzyme class is GTP 7,8-8,9-dihydrolase (diphosphate-forming). Other names in common use include guanosine triphosphate cyclohydrolase II, and GTP-8-formylhydrolase. This enzyme participates in riboflavin metabolism.

Structural studies[edit]

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 2BZ0 and 2BZ1.


  • Foor F, Brown GM (1975). "Purification and properties of guanosine triphosphate cyclohydrolase II from Escherichia coli". J. Biol. Chem. 250 (9): 3545–51. PMID 235552.