Enzymatic excision from gamma-irradiated polydeoxyribonucleotides of adenine residues whose imidazole rings have been ruptured.
AUTOR(ES)
Breimer, L H
RESUMO
The main forms of base damage in polydeoxyadenylic acid gamma-irradiated under hypoxic conditions are due to saturation and fragmentation of the adenine imidazole ring. An irradiated polymer was annealed with an equimolar amount of poly (dT) to generate a double-stranded polydeoxyribonucleotide containing scattered damaged base residues. On incubation of the latter with partially purified cell extracts of E.coli, imidazole ring-opened adenine, i.e. 4,6-diamino-5-formamidopyrimidine, was released in free form by a DNA glycosylase activity. The enzyme has been purified 4,500-fold, has Mr = 29,000, and appears to be identical with the previously described DNA repair enzyme formamidopyrimidine-DNA glycosylase.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=320082Documentos Relacionados
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