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Bioimpacts. 2019;9(1):15-23. doi: 10.15171/bi.2019.03. Epub 2018 Sep 13.

Highly efficient novel recombinant L-asparaginase with no glutaminase activity from a new halo-thermotolerant Bacillus strain.

Author information

1
Connective Tissue Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
2
Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran.
3
Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
4
Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
5
School of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
6
Faculty of Pharmacy, Near East University, POBOX:99138, Nicosia, North Cyprus, Mersin 10, Turkey.

Abstract

Introduction: The bacterial enzyme has gained more attention in therapeutic application because of the higher substrate specificity and longer half-life. L-asparaginase is an important enzyme with known antineoplastic effect against acute lymphoblastic leukemia (ALL). Methods: Novel L-asparaginase genes were identified from a locally isolated halo-thermotolerant Bacillus strain and the recombinant enzymes were overexpressed in modified E. coli strains, OrigamiTM B and BL21. In addition, the biochemical properties of the purified enzymes were characterized, and the enzyme activity was evaluated at different temperatures, pH, and substrate concentrations. Results: The concentration of pure soluble enzyme obtained from Origami strain was ~30 mg/L of bacterial culture, which indicates the significant improvement compared to L-asparaginase produced by E. coli BL21 strain. The catalytic activity assay on the identified L-asparaginases (ansA1 and ansA3 genes) from Bacillus sp. SL-1 demonstrated that only ansA1 gene codes an active and stable homologue (ASPase A1) with high substrate affinity toward L-asparagine. The Kcat and Km values for the purified ASPase A1 enzyme were 23.96s-1 and 10.66 µM, respectively. In addition, the recombinant ASPase A1 enzyme from Bacillus sp. SL-1 possessed higher specificity to L-asparagine than L-glutamine. The ASPase A1 enzyme was highly thermostable and resistant to the wide range of pH 4.5-10. Conclusion: The biochemical properties of the novel ASPase A1 derived from Bacillus sp. SL-l indicated a great potential for the identified enzyme in pharmaceutical and industrial applications.

KEYWORDS:

Bacillus sp. SL-1 ; Cloning; Origami; Recombinant L-asparaginase; Soluble overexpression

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