EXTRACTION AND PARTIAL PURIFICATION OF PROTEASE FROM LOCAL SERRATIA MARCESCENS ISOLATE

Serratia marcescens isolated from a patient with urinary tract infection taken from the Central Health Laboratory. The sensitivity test showed the resistant to the Tetracyclin (30μg), Amoxicillin (25 μg), Gentamycin(30 μg), ampicillin (10μg), and Kanamycin (30μg), but it was sensitive to Ciprofloxacin (5 μg) only. The extracellular protease was extracted in LB broth and purified in two step included precipitation with (30-55%) saturation of ammonium sulfate, dialysis and ion exchange chromatography by DEAE–Cellulose. Only one peak contained the enzymatic activity, and purification fold was 22.6 with 37.92% recovery. Based on the inhibitory effects of EDTA, the protease was characterized as a metalloproteinase. The enzyme activity was increased in the presence of Mg2+ and decreased in the presence of Cu2+ and Zn2+. The protease could also be activated by the non-ionic surfactants Tween 80 (1.0%) and Triton X-100 (1.0%).