Abstract

The enzyme L-Asparaginase II converts L-asparagine to L-aspartic acid and ammonia. It is currently used as a chemotherapeutic agent due to its antineoplastic effect in certain types of tumor cells which are not able to synthesize L-asparagine on their own1. However, L-asparaginase activity is usually associated to conversion of glutamine into glutamate and ammonium, generating side effects in treated patients, such as pancreatitis, leukopenia and thrombosis2. Also, long term L-asparaginase treatment generates immune response in patients, resulting in neutralization of its antitcancer effect3. These enzymes are broadly distributed in living organisms. However, enzymes from microorganism are the most used for therapies, due to its better efficiency and lower production cost. Among them, those synthesized by bacteria of the actinomycete order are of particular interest. For instance, the existence of an L-Asparaginase II from Streptomyces radiopugnans MS13 without glutaminase activity, responsible of adverse effects at physiological level, has been reported4. In the genome of the actinomycete Salinisporora tropica CNB440, it has been reported a putative sequence coding for an L-asparaginase II, which so far has not been characterized. Due to the interest in finding new L-asparaginase enzymes with low or no glutaminase activity and serologically different, we decided to heterogously express this sequence and characterize this enzyme in order to evaluate its potential to be use as chemotherapeutic agent.