[Analysis of the activity of Micrococcus luteus endonucleases with respect to gamma-irradiated DNA].
Endonucleases from Micrococcus luteus that induce single-strand breaks in gamma-irradiated DNA have been separated chromatographycally into two groups. The first group involves two different enzymes: AP-endonuclease II (mol. weight 30 000) and AP, UV-endonuclease I (mol. weight 15 000) that recognize alkali-labile lesions in gamma-irradiated DNA and apurinic sites in DNA heated at 70 degrees C, pH 6.08 AP-endonuclease II in cooperation with DNA polymerase from M. luteus and T4 phage-induced polynucleotide ligase is capable of carrying out in vitro complete excision repair of alkali-labile lesins in gamma-irradiated DNA. The second group involves gamma-endonucleases X and Y that act on alkalistable gamma-ray lesions. gamma-endonucleases X and Y can be separated by chromatography on DEAE-cellulose but possess similar properties. Activity of gamma-endonucleases toward gamma-irradiated DNA is inhibited by only heavily UV-irradiated DNA (15 000 ergs/mm2). The data are consistent with the hypothesis that gamma-endonucleases are specific for thymine glycols (t' and tUV) in UV- and gamma-irradiated DNA.
D004247:DNA / Q000378:metabolism* / Q000528:radiation effects; D004355:Drug Stability; D004720:Endonucleases / Q000378:metabolism*; D005720:Gamma Rays; D006863:Hydrogen-Ion Concentration; D008836:Micrococcal Nuclease / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008970:Molecular Weight; D011118:Polynucleotide Ligases / Q000378:metabolism; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays
D004247:DNA; D004720:Endonucleases; D008836:Micrococcal Nuclease; D011118:Polynucleotide Ligases
Analiz aktivnosti éndonukleaz kletok Micrococcus luteus po otnosheniiu K gamma-obluchennoĭ DNK.