Recombinant l-Asparaginase II from Lactobacillus casei subsp. casei ATCC 393 and Its Anticancer Activity.

Abstract

l-asparaginases from bacterial origin are employed extensively in leukemic treatment and food industry. The present study focuses on the characterization of the recombinant l-asparaginase II from Lactobacillus casei subsp. casei ATCC 393 cloned into Escherichia coli expression system and purified using Ni-NTA chromatography. The recombinant l-asparaginase as a monomer had a molecular weight of 35kDa. The enzyme was active from 10 to 80°C with the optimum at 40°C. The enzyme retained its activity at 28°C and 37°C up to 24h. The enzyme had optimum pH of 6 and retained 50% activity till 18h. The Km of the recombinant enzyme was 0.01235mM and Vmax 1.576mM/min. The half life of recombinant l-asparaginase II in human serum was 44h and trypsin was for 15min. The LC-MS/MS analysis revealed the molecular weight of 35,050 and pI of 5.64. The secondary structure prediction using CD spectroscopy for the recombinant enzyme showed 33.5% α-helix, 66.5% turn and 0% β sheets. The cytotoxicity of the recombinant enzyme was analysed against MOLT 3, Jurkat E6.1 and K-562 with the IC 50 value of 30, 62.5 and 50µg/ml.