Toxicological evaluation of asparaginase purified from E. cloacae.

(a) Non-toxic effects of purified asparaginase on noncancerous human epithelial cell line FR-2. Approximately, 1.5x10⁴ cells ml^-1 were cultured at 37°C and treated with 2, 5, 10, and 15 IU ml^-1 concentrations of purified asparaginasefor 48 h and cell viability was determined by the MTT assay. (b(i) Crude asparaginase formed clear translucent zone on blood agar plate due to lysis of erythrocytes. (b(ii) Purified asparaginase had no hemolytic effect. (c) Quantitative measure of the haemolytic activity. A: negative control (without asparaginase); B: positive control (Phosphate buffer); C: crude asparaginase; D: 15 IU ml^-1; E: 7.5 IU ml^-1; F: 3.75 IU ml^-1 concentrations of asparaginase.