A newly identified glutaminase-free ʟ-asparaginase (ʟ-ASPG86) from the marine bacterium Mesoflavibacter zeaxanthinifaciens

Conference Dates

September 24-28, 2017


ʟ-Asparaginase (EC is an enzyme involved in asparagine hydrolysis and has the potential to effect leukemic cells and various other cancer cells. We identified the ʟ-asparaginase gene (ʟ-ASPG86) in the genus Mesoflavibacter, which consists of a 1035-bp open reading frame (ORF) encoding 344 amino acids (aa). Following phylogenetic analysis, the deduced amino acid sequence of ʟ-ASPG86 (ʟ-ASPG86) grouped as a type I asparaginase with respective homologs in Escherichia coli and Yersinia pseudotuberculosis. The ʟ-ASPG86 gene was cloned into the pET-16b vector to express the respective protein in E. coli BL21 (DE3) cells. Recombinant ʟ-asparaginase (r-ʟ-ASPG86) showed optimum conditions at 37-40oC, pH 9. Moreover, r-ʟ-ASPG86 did not exhibit glutaminase activity. In the metal ions test, its enzymatic activity was highly improved upon addition of 5 mM manganese (3.97-fold) and magnesium (3.35-fold) compared with the untreated control. The specific activity of r-ʟ-ASPG86 was 687.1 units/mg under optimum conditions (37oC, pH 9 and 5 mM MnSO4).

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