Term Name:	GTP cyclohydrolase IIa activity
Synonyms:	GTP 8,9-dihydrolase (phosphate-forming), GTP 8,9-hydrolase (phosphate-forming), GTP cyclohydrolase III activity
Definition:	Catalysis of the reaction: GTP + 3 H2O = 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + 2 H+ + 2 phosphate.
Ontology:	GO: Molecular Function [GO:0043740]    QuickGO    AmiGO