Properties of an endonuclease activity in Micrococcus luteus acting on gamma-irradiated DNA and on apurinic DNA
| Autor: | P. Haas, G. Schäfer, U. Hagen, Th. Coquerelle |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
DNA
Bacterial Size-exclusion chromatography DNA-Directed DNA Polymerase Micrococcus Endonuclease chemistry.chemical_compound Centrifugation Density Gradient Escherichia coli Nucleotide AP site Magnesium chemistry.chemical_classification biology X-Rays Dose-Response Relationship Radiation General Medicine biology.organism_classification Endonucleases Molecular biology Enzyme chemistry Biochemistry Sephadex Gamma Rays Purines biology.protein Chromatography Gel Micrococcus luteus DNA |
| Zdroj: | International journal of radiation biology and related studies in physics, chemistry, and medicine. 37(1) |
| ISSN: | 0020-7616 |
| Popis: | A protein fraction from Micrococcus luteus with endonuclease activity against gamma-irradiated DNA was isolated and characterized. An additional activity on apurinic sites could not be separated, either by sucrose gradient sedimentation or by gel filtration through Sephadex G 100. From gel filtration, a molecular weight of about 25 000 was calculated for both endonuclease activities. The endonuclease activity against gamma-irradiated DNA was stimulated five-fold with 5 mM Mg++, whereas that against apurinic sites was less dependent on the Mg++ concentration. 100 mM KCl inhibited the gamma-ray endonuclease, but not the apurinic endonuclease activity. In gamma-irradiated RNA the protein recognized 1.65 endonuclease sensitive sites per radiation induced single-strand break, among which are 0.45 alkali labile lesions in the nucleotide strand. The affinity of the enzyme for the endonuclease sensitive site was evaluated resulting in a Km-value of 73 nM. |
| Databáze: | OpenAIRE |
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