Characterization of Protease isolated from Staphylococcus aureus local isolates at Hilla City, Iraq. Analytical chemical study

Abstract

 Background: Bacterial proteases playa vital role in clinical and industrial services. It regardsvirulence factorwhen produced from bacteria and can destroy the antibiotics (P-lactamases) and causes damage that may make the disease worsensor delay healing or may interfere with some portions of the immune system. Industrially proteases introduce for many applications like detergent production. The current study aims to isolate and characterize the proteases isolated from clinical isolates of staphylococci. Methodology: Sixty samples were collected from different clinical sources including swabs from wounds, burns, ulcers, urine, and blood, and diagnosed with mannitol salt agar medium using a biochemical test. Protease production, characterization, and purification were performed. Results: Thirty isolates were diagnosed as belonging to the genus Staphylococcus, which included 17 isolates of S. epidermises and 13 isolates of S. aureus. Only 10 isolates of A aureus can produce protease enzyme using Colombia papain medium containing sorting milk. The optimum conditions for the production were determined by the method of submerged farms using fructose as a source of Carbon at a concentration of 0.5% and peptone and yeast extract as nitrogen sources at a concentration of 1% and 0.5% 6 at an initial pH of 8 after 24 X 710 CFU/ ml, respectively. The medium was incubated for 1 hourat 35°C in a vibrating incubator at 150 rpm. The number of purification timeswas8.83withan enzymatic yield. It was obseived that the partially purified enzyme showed two protein bands when electrophoresis was performed on Polyacrylamide gel in the absence of protein teratogens. The molecular weight of the protease enzyme is 10000 Daltons by gel filtration method. The optimum conditions were: pH for enzyme activity is 8, and the optimum pH range for enzyme stability was between 7 and 9; temperature for enzyme activity was 40 °C. The value of the activation energy for converting the base materialintoa product wasdetermined at 6626.7 calories/mol. The enzyme retained its full activity when incubated for 30 minutes at 25°C Up to 80% of its effectiveness when incubated at 55 °C. For the enzyme, it was 7.5 mg/ml and 1.5 Vmax, and the maximum speed was -6 Km. Conclusion: It was found that the enzyme under study belongs to the group of serine proteases with a molecular weight of approximately 10,000