GTP cyclohydrolase II

In enzymology, a GTP cyclohydrolase II (EC 3.5.4.25) is an enzyme that catalyzes the chemical reaction

GTP + 3 H₂O ${\displaystyle \rightleftharpoons }$ formate + 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine + diphosphate

GTP cyclohydrolase II
Identifiers
EC no.	3.5.4.25
CAS no.	56214-35-8
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

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

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