APEX1（apurinic/apyrimidinic endodeoxyribonuclease 1），癌症关联基因，基因ID：328，无嘌呤/无嘧啶（AP）位点经常出现在DNA分子中，通过自发水解、DNA损伤剂或DNA糖基化酶去除特定的异常碱基AP位点是可以阻止正常DNA复制的突变前损伤，因此细胞含有识别和修复这些位点的系统II类AP内切酶将磷酸二酯主链5'切割到AP位点。该基因编码人类细胞中的主要AP内切酶这个基因的剪接变异体已经被发现，它们都编码相同的蛋白质。[由RefSeq提供，2008年7月]Apurinic/apyrimidinic (AP) sites occur frequently in DNA molecules by spontaneous hydrolysis， by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. AP sites are pre-mutagenic lesions that can prevent normal DNA replication so the cell contains systems to identify and repair such sites. Class II AP endonucleases cleave the phosphodiester backbone 5' to the AP site. This gene encodes the major AP endonuclease in human cells. Splice variants have been found for this gene; all encode the same protein. [provided by RefSeq， Jul 2008]。