Our data show that ScASNase1 has characteristics described for the two subfamilies of l-asparaginase, types I and II, and may have promising antineoplastic properties.ĭetermination of specific activity, optimum reaction conditions and kinetic characterisation for ScASNase1 enzyme. Furthermore, ScASNase1 showed cytotoxicity for the MOLT-4 leukemic cell lineage. We showed through site-directed mutagenesis that the T64-Y78-T141-K215 residues are involved in catalysis. ScASNase1 has specific activity of 196.2 U/mg and allosteric behaviour, like type I enzymes, but with a low K 0.5 = 75 μM like therapeutic type II. Here we characterised ScASNase1 using a recombinant enzyme purified by affinity chromatography. The yeast Saccharomyces cerevisiae has the ASP1 gene responsible for encoding L-asparaginase 1 (ScASNase1), an enzyme predicted as type II, like bacterial therapeutic isoforms, but it has been poorly studied. Therefore, alternative sources of L-ASNase may be useful to reduce toxicity and enhance efficacy. However, bacterial enzymes are susceptible to induce immune responses, leading to a high incidence of adverse effects compromising the effectiveness of the treatment. The bacterial enzymes family is subdivided in type I and type II nevertheless, only type II have been employed in therapeutic proceedings. Currently, the enzyme is obtained from bacteria, Escherichia coli and Erwinia chrysanthemi. L-asparaginase (L-ASNase) (EC 3.5.1.1) is an important enzyme for the treatment of acute lymphoblastic leukaemia.
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