title: Endonuclease from Micrococcus luteus which has activity toward ultraviolet-irradiated deoxyribonucleic acid: purification and properties.
abstract: An endonuclease purified approximately 3,200-fold from Micrococcus luteus is active on native ultraviolet-irradiated deoxyribonucleic acid (DNA), but is inactive on unirradiated native or denatured DNA and has no activity toward irradiated denatured DNA. The major type of lesion for the nucleolytic activity is the cyclobutane pyrimidine dimer. The enzyme makes a number of single-strand breaks approximately equal to the number of dimers, but dimers are not excised. This endonuclease-a small molecular weight protein-therefore has all the attributes hypothesized for the first enzyme in the sequential steps in repair of DNA in vivo. Another paper shows that the endonuclease is able to reactivate ultraviolet-irradiated transforming DNA.
mesh_terms: D002247:Carbon Isotopes; D002845:Chromatography; D002850:Chromatography, Gel; D004269:DNA, Bacterial / Q000378:metabolism* / Q000528:radiation effects; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli; D008836:Micrococcal Nuclease / Q000302:isolation & purification; D008837:Micrococcus / Q000201:enzymology*; D008970:Molecular Weight; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification*; D010759:Phosphorus Isotopes; D011743:Pyrimidines / Q000378:metabolism; D013936:Thymidine; D014316:Tritium; D014466:Ultraviolet Rays
chemical_list: D002247:Carbon Isotopes; D004269:DNA, Bacterial; D010759:Phosphorus Isotopes; D011743:Pyrimidines; D014316:Tritium; D003851:Deoxyribonucleases; D010744:Phosphoric Monoester Hydrolases; D008836:Micrococcal Nuclease; D013936:Thymidine