Purification and Characterization of Thermo Stable DNase of Staphylococcus Aureus Isolated from Different Clinical Source

Hundred samples were collected from different clinical source. Sixty isolates identified asStaphylococcus aureus. The ability of S. aureus to produce DNase was examined phenotypically on DNaseagar medium and also by quantitative assay that revealed only 37(66%) able producethe enzyme. extracted, the crude activity specific 38 (U/ml) 253.3(U/mg)respectively. enzyme purified precipitating with ammonium sulphate at (65-85 %) saturation thenby using ion exchange chromatography in CM cellulose gel filtration Sephadex G150.Purified 42 4200(U/mg) respectively. optimumPH for found be 8 while stable wide range pH (8, 9 10) withremaining 100%, 90%, 86% optimum temperature 37 oC whilethe stability oC. Results indicate increased when wasincubated 10 mM each MnCl2, KCl, NaCl, MgCl2, CaCl2. molecular weight DNasewas done approximately 19KDa.