Title:An Antileukemic Glutaminase Free L-Asparaginase from Bacillus brevis
Volume: 6
Issue: 1
Author(s): Wamik Azmi, Umesh Kumar Narta, Nishant Singh, Vibhor Gupta, Shamsher Singh Kanwar and Sarita Devi
Affiliation:
Keywords:
Acute Lymphoblastic Leukemia (ALL). Bacillus brevis, glutaminase free L-asparaginase, intracellular enzyme,
one-step purification, MTT assay.
Abstract: Background: The antitumor activity of L-asparaginase isolated from natural sourceshas been proven
thriving in treatment of acute lymphoblastic leukemia and other lymphoproliferative disorders however
production efficiency and associated glutaminase activity has always been a limitation to its use.
Asparaginase also induces apoptosis and cytoprotective autophagy in chronic myeloid leukemia cells.
Together these findings make L-asparaginase a useful drug for the treatment of Acute Lymphocytic
Leukemia and various other tumors.
Methods: In the present study, the purification and characterization of a glutaminasefree intra-cellular
L-asparaginase was done from Bacillus brevis, originally isolated from a cold desert region of Himachal
Pradesh, India.
Results: The enzyme was purified to 90-fold by a SulphopropylSephadex columnchromatography and
found to be 32 kDa in molecular weight under reduced conditions. The enzyme possessed significant
amount of activity at human physiological conditions of temperature (37°C) and pH (7.4) and have a
half-life of 70 minutes at 25ºC. The Km and Vmax values of L-asparaginase were found to be 3.5 X
10-2 M and 0.77 IU, respectively. The L-asparaginase purified from B. brevis showed comparable in
vitro toxicity on Hep-2C cell lines (91% survival) in comparison to commercial L-asparaginase
preparation (90% survival) obtained from E. coli.
Conclusion: L-asparaginase with high purity and high affinity for L-asparagine will bemost suitable for
the treatment of lymphoblastic leukemia. The glutaminase free L-asparaginase obtained from B. brevis
thus provides an additional therapeutic agent and could be used against for the treatment of various
malignant diseases.
