GTP cyclohydrolase IIa activity
Catalysis of the reaction: GTP + 3 H2O = 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + 2 H+ + 2 phosphate.
GO:0003933
GTP cyclohydrolase activity
is_a
GTP 8,9-dihydrolase (phosphate-forming)
related
GTP 8,9-hydrolase (phosphate-forming)
exact
GTP cyclohydrolase III activity
narrow