Puriffication and characterization of L-asparaginase produced by Streptomyces phaeochromogenes FS-39

ABSTRACT

An L-asparaginase [EC.3.5.1.1] produced by Streptomyces phaeochromogenes FS-39 was purified and characterized. After initial ammonium sulfate fractionation [50-70% saturation], the enzyme was purified by consecutive column chromatography on ion exchange [DEAE-Cellulose] and Sephadex G-200 filtration. The 67.2 fold purified enzyme thus obtained has the specific activity of 179.14 units mg protein super [-1] with an over all recovery of 17.7%. The enzyme was characterized by demonstration of optimum activity at 35°C and pH 8.5. It was stable for 180 min. at 30-35°C and 7 days at 4°C [refrigerator] and pH range from 8.0 to 9.0. The enzyme activity was slightly stimulated by Mg supper [2+], Fe super [2+] and Ca super [2+] cations, but Na-azid and EDTA did not exert any effect on the enzyme activity. Hg super [2+], Ag super [+] and Cu super [2 +] cations as well as L-cysteine, iodine, KCN and iodoacetic acid strongly inhibited the enzyme, but Zn super [2+], KMnO4 and super [2+] potentially slightly inhibited the enzyme activity. L-aspartic acid was competitive inhibitor