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...

L-asparaginase is a hydrolase that catalyzes the conversion of L-asparagine--an endogenous amino acid necessary for the function of some neoplastic cells, such as lymphoblasts. In most human cells deficiency of L-asparagine can be compensated by alternative synthesis pathway through which L-asparagine is produced from aspartic acid and glutamine by asparagine synthethase. Depletion of L-asparag...

L-asparaginase from bacteria has been used in treatment of acute lymphoblastic leukemia. The aim of this study was to purify and characterize L-asparaginase from Phaseolus vulgaris seeds instead of microbial sources. L-asparaginase was purified to apparent homogeneity. The enzyme has molecular mass of 79 kDa. The purified asparaginase had very low activity toward a number of asparagine and glut...

l-Asparaginase is now known to be a potent antineoplastic agent in animals and has given complete remission in some human leukemias. Extensive clinical trials of this enzyme, however, were not possible in the past because of inadequate production of this substance. We have developed practical procedures for producing l-asparaginase in yields of sufficient quantity and purity for more extensive ...

Three hundred and sixty four (364) isolates of tropical soil fungi were screened for L-asparaginase production by rapid plate method using modified Czapek-Dox agar containing L-asparagine, and either bromo cresol purple or phenol red dye as an indicator. Results of the study revealed that total one hundred and thirty five (135) isolates showed positive reaction for L-asparaginase production as ...

BACKGROUND l-Asparaginase is essential in the treatment of childhood acute lymphoblastic leukemia. If immunoglobulin G anti-l-asparaginase antibodies develop, they can lead to faster plasma clearance and reduced efficiency as well as to hypersensitivity reactions, in which immunoglobulin E can also participate. This study investigated the presence of immunoglobulin G and immunoglobulin E anti-l...

L-asparaginase is an important enzyme as therapeutic agents used in combination with other drugs in the treatment of acute lymphoblastic leukemia. A newly isolated actinomycetes strain, Streptomyces sp. NEAE-82, was potentially producing extracellular L-asparaginase, it was identified as Streptomyces fradiae NEAE-82, sequencing product was deposited in the GenBank database under accession numbe...

The acute effects of a single intravenous dose of L-asparaginase on protein synthesis were studied in normal rabbits and in animals that had received turpentine to stimulate fibrinogen production. Male New Zealand rabbits received L-asparaginase (500 U/kg) 16 hr before the injection of the radiolabeled amino acid [75Se]selenomethionine (75SeM). Incorporation of 75SeM into fibrinogen and serum p...

Of 15 L-asparaginase preparations tested, 13 inhibited whole human serum complement; the inhibitory effect ranged from 12 to 45%. We have partially characterized the anticomplementary activity in one of the L-asparaginase preparations. The anticomplementary activity was separable from the L-asparaginase activity on Sephadex G-200. Fractions containing L-asparaginase had no effect either on whol...

This paper describes optimization method that combines the Plackett-Burman design, a factorial design and the response surface method, which were used to optimize the medium for the production of L-asparaginase by Serratia marcescens SB08. Four medium factors, from out of 11 medium factors, were screened by Plackett-Burman design experiments and subsequent optimization process to find out the o...