ENTRY       EC 3.5.4.25
NAME        GTP cyclohydrolase II
CLASS       Hydrolases
            Acting on carbon-nitrogen bonds, other than peptide bonds
            In cyclic amidines
SYSNAME     GTP 7,8-8,9-dihydrolase (pyrophosphate-forming)
REACTION    GTP + 3 H2O = Formate +
            2,5-Diamino-6-hydroxy-4-(5'-phosphoribosylamino)-pyrimidine +
            Pyrophosphate
SUBSTRATE   GTP
            H2O
PRODUCT     Formate
            2,5-Diamino-6-hydroxy-4-(5'-phosphoribosylamino)-pyrimidine
            Pyrophosphate
COMMENT     Two C-N bonds are hydrolysed, releasing formate, with
            simultaneous removal of the terminal pyrophosphate.
PATHWAY     PATH: MAP00740  Riboflavin metabolism
GENES       MJA: MJ0055
            MTH: MTH1499
            ECO: b1277(ribA)
            HIN: HI0212(ribA)
            HPY: HP0802(ribA) HP0804
            BSU: ribA
            SYN: sll1894(ribA)
            SCE: YBL033C(RIB1)
DBLINKS     University of Geneva ENZYME DATA BANK: 3.5.4.25
            WIT (What Is There) Metabolic Reconstruction: 3.5.4.25
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