title: Micrococcus luteus correndonucleases. I. resolution and purification of two endonucleases specific for DNA containing pyrimidine dimers.
abstract: Five peaks of endonuclease activity showing a preference for ultraviolet-damaged DNA have been chromatographically identified from extracts of Micrococcus luteus. They are numerically designated as I to V in order of their elution from phosphocellulose (Whatman P-11) columns. The first two of these peaks have been highly purified by a combination of gel filtration and affinity chromatography and are catalytically homogeneous judging from their effect on transforming DNAs. Peak I, which has an isoelectric point of 4.7, is heat-stable, requires high ionic strength for optimal activity, acts with equal facility on ultraviolet-irradiated native and denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease I. Peak II which has a pI value of 8.7, is heat-labile, is inhibited by high ionic strength, acts on ultraviolet-irradiated native but not denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease II. Both enzymes are inhibited by Ca2+ and Zn2+, do not show any cofactor or sulfhydryl requirement, act optimally between pH 7.0 and 7.4, and have molecular weights between 11,000 and 15,000. Py pyrimidine dimer Py correndonuclease I requires a dose about 1.6 times that for Py pyrimidine dimers Py correndonuclease II for incision saturation of irradiated phiX174 RFI DNA.
mesh_terms: D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000528:radiation effects; D003851:Deoxyribonucleases / Q000302:isolation & purification* / Q000378:metabolism; D004720:Endonucleases / Q000302:isolation & purification* / Q000378:metabolism; D007525:Isoelectric Focusing; D008837:Micrococcus / Q000201:enzymology*; D011740:Pyrimidine Dimers; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; D004247:DNA; D003851:Deoxyribonucleases; D004720:Endonucleases