Background:L-asparaginase has been used as a chemotherapeutic agent in treatment of lymphoblastic leukemia. In the present investigation, Bacillus sp. PG03 and Bacillus sp. PG04 were studied.Methods:L- asparaginases were produced using different culture media and were purified using ion exchange chromatography.Results:Maximum productivity was obtained when asparagine was used as the nitrogen source at pH 7 and 48 h after cultivation. New intracellular L-asparaginases showed an apparent molecular weight of 25 kDa and 30 kDa by SDS-PAGE respectively. These enzymes were active in a wide pH range (3-9) with maximum activity at pH 6 for Bacillus PG03 and pH 7 for Bacillus PG04 L-asparaginase. Bacillus PG03 enzyme was optimally active at 37 ˚C and Bacillus PG04 maximum activity was observed at 40˚C. Kinetic parameters km and Vmax of both enzymes were studied using L-asparagine as the substrate. Thermal inactivation studies of Bacillus PG03 and Bacillus PG04 L-asparaginase exhibited t1/2 of 69.3 min and 34.6 min in 37 ˚C respectively. Also T50 and ∆G of inactivation were measured for both enzymes.Conclusion: The results revealed that both enzymes had appropriate characteristics and thus could be a potential candidate for medical applications.

Bacterial L-asparaginases are amidohydrolases that act on Lasparagine and produce L-aspartate and ammonia. These enzymes have been used in treatment of lymphoblastic leukemia. In the present study, a novel strain, Bacillus sp. PG02 was explored for the production of intracellular L-asparaginase enzyme. The nitrogen source for L-asparaginase production was L-asparagine. New intracellular L-asparaginase was purified using ion exchange chromatography and the purity was assessed using SDS-PAGE. Kinetic parameters k m and V max and thermal properties were studied using L-asparagine as the substrate. SDS-PAGE analysis showed apparent molecular weight of approximately 38 kDa. The enzyme was active in a wide pH ranges (5-10) and it was maximally active at pH 7.5. Bacillus PG02 L-asparaginase was optimally active at 40°C. Thermal inactivation studies exhibited t 1/2 of 32.5 min in 37°C. Also T 50 and ∆G of inactivation were measured. The results revealed that the enzyme had appropriate characteristics and thus could be a potential candidate for medical and basic investigations.