Backgroung and Aims: L-Asparaginase II is a cornerstone of treatment protocols for acute lymphoblastic leukemia. Only asparaginase II obtained from E. coli K12 and Erwinia chrysanthemi have been used in human as therapeutic drug. The therapeutic effects of asparaginase II from E. coli K12 and Erwinia chrysanthemi is accompanied by side effects. It is desirable to search for other asparaginase I...

Among the two types of bacterial L-asparaginases, only type II enzymes have been used inthe treatment of acute lymphoblastic leukemia owing to their higher affinity for L-asparagine.However, current screening media used for the isolation of L-asparaginase-producingmicroorganisms do not discriminate between the two types of L-asparaginase. During anoptimization study conducted to increase L-aspa...

Among the two types of bacterial L-asparaginases, only type II enzymes have been used inthe treatment of acute lymphoblastic leukemia owing to their higher affinity for L-asparagine.However, current screening media used for the isolation of L-asparaginase-producingmicroorganisms do not discriminate between the two types of L-asparaginase. During anoptimization study conducted to increase L-aspa...

Saccharomyces cerevisiae X2180-1A synthesizes two forms of asparaginase: L-asparaginase I, an internal constitutive enzyme, and asparaginase II, an external enzyme which is secreted in response to nitrogen starvation. The two enzymes are biochemically and genetically distinct. The structural gene for asparaginase I (asp 1) is closely linked to the trp 4 gene on chromosome IV. The gene controlli...

Escherichia coli expresses two L-asparaginase (EC 3.5.1.1) isozymes: L-asparaginse I, which is a low affinity, cytoplasmic enzyme that is expressed constitutively, and L-asparaginase II, a high affinity periplasmic enzyme that is under complex co-transcriptional regulation by both Fnr and Crp. The distinct localisation and regulation of these enzymes suggest different roles. To define these rol...

The biosynthesis of asparaginase II in Saccharomyces cerevisiae is subject to nitrogen catabolite repression. In the present study we examined the physiological effects of glutamate auxotrophy on cellular metabolism and on the nitrogen catabolite repression of asparaginase II. Glutamate auxotrophic cells, incubated without a glutamate supplement, had a diminished internal pool of alpha-ketoglut...

Among the two types of bacterial L-asparaginases, only type II enzymes have been used in the treatment of acute lymphoblastic leukemia owing to their higher affinity for L-asparagine. However, current screening media used for the isolation of L-asparaginase-producing microorganisms do not discriminate between the two types of L-asparaginase. During an optimization study conducted to increase L-...

background: in the recent years, there has been an increasing interest in secretory production of recombinant proteins, due to its various advantages compared with intracellular expression. signal peptides play a critical role in prosperous secretion of recombinant proteins. accordingly, different signal peptides have been assessed for their ability to produce secretory proteins by trial-and-er...

The aim of this investigation was to compare the efficacy of the permeabilization methods of microwave irradiation and potassium phosphate (KPi)-hexane solvent system in isolating the periplasmic enzyme, L-asparaginase II. Previous studies have shown that both methods enable the isolation of periplasmic proteins in Gram-negative bacteria. Periplasmic, cytoplasmic and membrane fractions of Esche...