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Abstract

A novel fibrinolytic protease from Bacillus circulans GD25 was isolated and characterized for the fibrinolytic activity. The fibrinolytic protease was purified by ammonium sulphate fractionation (70%) and subjected to chromatographic methods like Sephadex G-50, DEAE-Sephadex A-50 columns. The purified enzyme has an approximately 38 kDa in size by SDS-PAGE and gel filtration. Optimum activity was at 35ºC and the enzyme was highly active over a wide range of pH from 7.0-9.0 with an optimum at pH 8.0. It exhibited stronger fibrinolytic protease activity. The activity was slightly enhanced by Ca 2+ and Mg 2+ whereas Zn 2+, Cu 2+, Co 2+ and Fe 2+ suppressed the activity. The fibrinolytic protease activity was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine metallo-protease with potential application in thrombolytic therapy INTRODUCTION: Proteases are proteolytic enzymes which catalyze the hydrolysis of proteins based upon their structures or properties of the active site. There are several kinds of proteases such as serine, metallo, carboxyl, acidic, neutral and alkaline proteases. Proteases are industrially important due to their wide applications in leather processing, detergent industry, food industries, pharmaceutical and textile industry etc 1, 2. Proteases are obtained from plants, animal organs and microorganisms, with the majority obtained from microbial sources. Currently, a large proportion of commercially available proteases are derived from bacteria and fungi.