Fusarium sp. L-Asparaginases: purification, characterization and potential assessment as anti-leukemic chemotherapeutic agent

Abstract

Asparaginases play an important role in the treatment of leukemia. It is part of chemotherapy in the treatment of leukemia in the last three decades. L-Asparaginase isolated from Fusarium sp. isolated from soil and purified using ammonium sulfate precipitation and Sephadex G 100. Characterization of the crude enzyme revealed it is a metalloprotease inhibited by EDTA. Hg2+, Cd2+, and Pb2+ also inhibited the enzyme. Mg2+, Zn2+ and Ca2+ activated L. asparaginase. Further, the kinetic studies of purified enzyme were carried out. Vmax and Km and were 0.031 M and 454 U/mL, respectively. The optimum temperature was 30°C, optimum pH was 7. Concerning substrate specificity; gelatin and casein in addition to L-asparagine were tested. The enzyme was found to be non-specific, could hydrolyze all tested substrates at different rates. Maximum enzyme activity was recorded in the case of L-asparagine, followed by Casein and gelatin, respectively. The molecular weight of L-Asparaginase was 22.5 kDa. The Anti-leukemic cytotoxicity assay of the enzyme against RAW2674 leukemic cell lines by MTT viability test was estimated. The enzyme exhibited anti-leukemic activity with IC50 of 70 Uml− 1 and relative viability 70 % of control. The current work presents additional information regarding the purification and characterization of the enzyme produced by Fusarium sp. and its evaluation as a potential anti-leukemic chemotherapeutic agent.