ENTRY       EC 4.3.2.4
NAME        Purine imidazole-ring cyclase
CLASS       Lyases
            Carbon-nitrogen lyases
            Amidine-lyases
SYSNAME     DNA-4,6-diamino-5-formamidopyrimidine C8-N9-lyase (cyclizing)
REACTION    DNA 4,6-diamino-5-formamidopyrimidine = DNA adenine + H2O
SUBSTRATE   DNA 4,6-diamino-5-formamidopyrimidine
PRODUCT     DNA adenine
            H2O
COMMENT     Also acts on 2,6-diamino-5-formamido-3,4-dihydro-4-oxopyrimidine
            residues. Brings about the reclosure of the imidazole rings of
            purine residues damaged by gamma-rays.
DBLINKS     University of Geneva ENZYME DATA BANK: 4.3.2.4
            WIT (What Is There) Metabolic Reconstruction: 4.3.2.4
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