ENTRY       EC 3.5.4.16
NAME        GTP cyclohydrolase I
CLASS       Hydrolases
            Acting on carbon-nitrogen bonds, other than peptide bonds
            In cyclic amidines
SYSNAME     GTP 7,8-8,9-dihydrolase
REACTION    GTP + 2 H2O = Formate + 2-Amino-4-hydroxy-6-(erythro-
            $1,2,3-trihydroxypropyl)-dihydropteridine triphosphate
SUBSTRATE   GTP
            H2O
PRODUCT     Formate
            2-Amino-4-hydroxy-6-(erythro-1,2,3-trihydroxypropyl)-
            $dihydropteridine triphosphate
COMMENT     The reaction involves hydrolysis of two C-N bonds and
            isomerization of the pentose unit; the recyclization may
            by non-enzymic.
PATHWAY     PATH: MAP00790  Folate biosynthesis
DISEASE     MIM: 600225  GTP cyclohydrolase 1; Phenylketonuria, atypical, due
                         to GCH1 deficiency, 233910 (1); Dystonia,
                         DOPA-responsive, 128230 (3)
MOTIF       PS: PS00859  [DE]-[LIVM](2)-x-[LIVM]-[KRN]-D-[LIVM]-x(3)-S-x-C-E-H-H
            PS: PS00860  R-x-Q-[LIVM]-Q-E-R-[LIVM]-T
GENES       ECO: b2153(folE)
            HIN: HI1447(folE)
            HPY: HP0928(folE)
            BSU: mtrA
            SYN: slr0426(folE)
            SCE: YGR267C(FOL2)
            HSA: GCH1(GCH)
STRUCTURES  PDB: 1GTP  
DBLINKS     University of Geneva ENZYME DATA BANK: 3.5.4.16
            WIT (What Is There) Metabolic Reconstruction: 3.5.4.16
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