Grossman L
Natl Cancer Inst Monogr. 1981 Dec(58):189-92.
DNA repair proficiency in cells is expressed by various enzymes which can recognize damaged sites arising from exogenous agents or endogenous conditions. Either a damaged base is recognized by DNA glycosylases, partially removed by hemi-DNA glycosylases acting on diadduct damage, or direct incision of the phosphodiester bond near the damaged site. Incision at those apurinic or apyrimidinic sites arising from depurination-depyrimidination or glycosylase reactions is effected by apurinic or apyrimidinic endonucleases. Excision of damaged sites is catalyzed by unique exonucleases followed by DNA polymerase catalyzed reinsertion of nucleotides. The integrity of the strands is restored by polynucleotide ligase when a juxtaposed nucleotide is properly reinserted.
细胞中的DNA修复能力由多种酶来体现，这些酶能够识别由外源性因素或内源性条件引起的损伤位点。受损碱基要么被DNA糖基化酶识别，通过作用于双加合物损伤的半DNA糖基化酶部分去除，要么在损伤位点附近直接切割磷酸二酯键。由脱嘌呤 - 脱嘧啶或糖基化酶反应产生的无嘌呤或无嘧啶位点的切割由无嘌呤或无嘧啶内切核酸酶完成。受损位点的切除由独特的外切核酸酶催化，随后由DNA聚合酶催化核苷酸的重新插入。当相邻核苷酸正确重新插入时，多核苷酸连接酶可恢复链的完整性。
