Endodeoxyribonuclease IV Endonuclease IV plays a role in DNA repair. It cleaves phosphodiester bonds at apurinic or apyrimidinic sites (AP sites) to produce new 5'-ends that are base-free deoxyribose 5-phosphate residues. It preferentially attacks modified AP sites created by bleomycin and neocarzinostatin (By similarity). END4_BACSU nfo Probable endonuclease 4 297 BSU25130 MLRIGSHVSMSGKHMLLAASQEAVSYGANTFMIYTGAPQNTRRKKIEDLNIEAGRAHMQENGIDEIIVHAPYIINIGNTTNPSTFELGVDFLRSEIERTAAIGAKQIVLHPGAHVGAGAEAGIKKIIEGLNEVIDPNQNVQIALETMAGKGSECGRSFEELAQIIEGVTHNEQLSVCFDTCHTHDAGYNIVEDFDGVLNEFDKIIGIDRIKVLHINDSKNVKGARKDRHENIGFGEIGFDALQYVVHHEQLKDIPKILETPYVGEDKKNKKPPYRFEIEMLKEKQFDDTLLEKILQQ Endonuclease IV yqfS