Purine imidazole-ring cyclase explained

purine imidazole-ring cyclase
Ec Number:	4.3.2.4
Cas Number:	95990-28-6
Go Code:	0050230

The enzyme purine imidazole-ring cyclase (EC 4.3.2.4) catalyzes the chemical reaction

DNA 4,6-diamino-5-formamidopyrimidine

\rightleftharpoons DNA adenine + H₂O

This enzyme belongs to the family of lyases, specifically amidine lyases. The systematic name of this enzyme class is DNA-4,6-diamino-5-formamidopyrimidine C⁸-N⁹-lyase (cyclizing DNA-adenine-forming). Other names in common use include DNA-4,6-diamino-5-formamidopyrimidine 8-C,9-N-lyase (cyclizing), DNA-4,6-diamino-5-formamidopyrimidine 8-C,9-N-lyase (cyclizing, DNA-adenine-forming).

References

• Chetsanga CJ, Grigorian C . 1985 . In situ enzymatic reclosure of opened imidazole rings of purines in DNA damaged by γ-irradiation . Proc. Natl. Acad. Sci. U.S.A. . 82 . 633 - 7 . 3856219 . 10.1073/pnas.82.3.633 . 3 . 397099 . 1985PNAS...82..633C . free .