Heterologus expression and activity evaluation of L-asparaginase II from Salinispora tropica, a possible chemotherapeutic agent

Llanovarced, Nyna; Asenjo, Juan A.; Andrews B. A.


The enzyme L-asparaginase II, which hydrolyzes L-asparagine in aspartic acid and ammonium, is currently used as a chemotherapeutic agent in the treatment of different types of cancer, due to its antineoplastic effect on certain types of tumor cells. Despite its successful role in the aforementioned treatment, its use is constantly reevaluated as it has adverse side effects, associated with a nonspecific activity towards a second substrate, glutamine. Given the need to find new asparagininases with low or no glutaminase activity, a novel L-asparaginase II described in the genome of the Salinispora tropica CNB 440 actinobacterium was studied. For this, the gene coding for the L-asparaginase II enzyme was amplified from the S.tropica genome CNB 440 and cloned into the expression vector pET22b (+), with which E.coli strains BL21 (DE3) were transformed. Subsequently, the expression of the construct was induced with IPTG in co-transformed cells, producing the protein. The activity of the enzyme L-asparaginase II was evaluated by Nesslerization, from crude extracts, for the substrates L-asparagine and Lglutamine, obtaining a specific asparaginase activity of 117.81 U/mg, without significant glutaminase activity. Given the promising results here presented, the evaluation of the activity of the purified enzyme and its characterization are suggested for future work.

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Fecha de publicación: 2019
Año de Inicio/Término: 2019