Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.1 (asparaginase)
2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rabbit antisera against L-asparaginase preparations from Escherichia coli, Erwinia carotovora, Citrobacter sp. and Chromobacterium violaceum showed on immunoelectrophoresis that only the enzymes from E. coli and Citrobacter are immunologically related. Purified preparations had to be used to determine the immunological cross-reactions. Immunoelectrophoresis at different pH values yielded the zero mobility points of the enzymes. The activity of the Er. carotovora preparation was enhanced up to fourfold by homologous antiserum but not by normal sera. Heterologous antisera also enhanced, but only at a higher concentration. Less enhancement was observed for the other enzymes with antisera as well as with bovine serum albumin. Inhibition was not observed.
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PMID:Immunological relationships of bacterial L-asparaginases. 5 4

In 42 children being in the advanced stage of an acute lymphoblastic leukaemia as well in 7 children with lymphosarcoma a total of 83 series of treatment with L-asparaginase were carried out. During the first blastic crisis of acute leukaemia 74% of complete or partial remissions could be obtained by two treatments and 52% by the following ones. The best results were obtained by organ manifestations of acute leukaemia (80% of complete or partial remissions). Less satisfactory results were achieved in treating lymphosarcoma. All remissions were only of a short duration.
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PMID:[Repeated, 2-10 fold asparaginase treatments in children with lymphoproliferative diseases]. 6 4

Bovine gammaglobulin-L-asparaginase conjugates were prepared with an enzymic activity of about 30 IU/mg. Glutardialdehyde was used as bifunctional reagent for the cross-linking in an optimal concentration of 0.16 mg/10 mg protein. The both components were found in the conjugates in a ratio of 1:1.5. The recovery was about 25% of the initial protein amounts. The antigenic specificity of the globulin component decreased up to 60%, the enzymic activity also up to 60% by the conjugation.
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PMID:[Conjugation of bovine gammaglobulin to L-asparaginase (E. coli) (author's transl)]. 6 93

Obvious protection of the catalytic activity of Esch. coli L-asparaginase by alpha 2-macroglobulin (alpha 2M) was observed under conditions otherwise propitious to the dissociation of the tetrameric molecule into inactive subunits, i.e. very diluted enzyme solutions or the presence of either SDS or urea. The degree of protection depended on enzyme and alpha 2M concentrations respectively, and on the preincubation time of the alpha 2M-enzyme mixture prior to substrate addition. The formation of a catalytically active complex between alpha 2M and L-asparaginase was confirmed by gel filtration on a Sephadex-G column and by polyacrylamide gel electrophoresis. The fact that the migration distance of the active complex corresponded to the migration of alpha 2M and the absence in that case of a migration band corresponding to the intact molecule suggest that complexing of the enzyme with alpha 2M prevented its dissociation into subunits and thus its inactivation. Addition of alpha 2M to the already dissociated enzyme molecule did not restore its catalytic activity. Alpha2-macroglobulin was shown to have an inhibiting effect on the proteolytic activity of almost all proteases and no effect on their esterolytic activity. Furthermore, it prevents the inhibition of esterolytic activity by some natural compounds. The effect of alpha 2M on other types of catalytic activity has not been investigated enough to afford a generalization of the possible role of this macroglobulin in the control of enzyme activity in the body. This paper reports the results of an in vitro study of the effect of alpha 2M on the catalytic activity of an important amidase, i.e. L-asparaginase (L-asparagine amidohydrolase 3.5.1.1), which in recent years has been used in the treatment of acute lymphocytic leukemia in children.
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PMID:Interaction of alpha 2-macroglobulin with L-asparaginase. 9 Mar 34

Amino acid and oligoamide derivatives of D-asparagine and L-asparaginic acid (L-asparaginase inhibitors) have been synthesized. An increase in the hydrophobic capacity of the modified inhibitor increases the inhibition constant. Once the modified inhibitor binds with Sepharose 6B, the length of the spacer (a chain of atoms attaching the inhibitor to the polymer matrix) determines affinity of the sorbent for L-asparaginase. On these sorbents affinity shifts from pH optimum of the enzyme activity to pH 4-5. The enzyme of E. coli L-asparaginase has been purified.
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PMID:[Synthesis and study of biospecific sorbents for isolating and purifying L-asparaginase from Escherichia coli]. 9 26

Reconstituted bovine collagen has been used extensively in our laboratory as a carrier for immobilized E. coli L-asparaginase. The activity and catalytic stability of these collagen-asparaginase membranes can be altered substantially by conditions used in membrane crosslinking with glutaraldehyde. As the concentration of glutaraldehyde used in tanning is increased, the initial specific activity of collagen-asparaginase membranes decreased asymptotically to a limiting value. Similar results occurred when membranes were subjected to increasing time periods of tanning at a constant glutaraldehyde concentration. These observations point to a time-concentration relationship for glutaraldehyde tanning and its effect on the specific activity of collagen-asparaginase membranes. Specific activities of membranes tanned a glutaraldehyde concentrations of 5% or higher appear to be very stable over long periods of alternate storage and assay. This result, however, is not observed with membranes tanned at glutaraldehyde concentrations lower than 5% for short periods of time (approximately 30 sec to 1 min). It is not clear whether the instability of membranes tanned at lower concentrations of glutaraldehyde or shorter intervals of tanning is due to enzyme elution from the membrane or denaturation of the bound enzyme.
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PMID:L-asparaginase bound to collagen membranes: effect of glutaraldehyde crosslinking on stabilization of catalytic activity. 9 29

The inactivation of E. coli asparaginase by 2,3-butanedione studied with L-asparagine and diazooxonorvaline as substrates obeys pseudo first order kinetics. Activity losses are linear with respect to arginine and histidine modification, with complete inactivation being correlated with alteration of one arginine and one histidine per subunit. The rate of inactivation of the enzyme was reduced in the presence of competitive inhibitors like L-2-amino-2-carboxyethane-sulfonamide. Under comparable conditions 1,2-cyclo hexanedione does not affect the activity of L-asparaginase.
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PMID:Inhibition of E. coli L-Asparaginase by reaction with 2,3-butanedione. Chemical modification of arginine and histidine residues. 16 Jun 98

The cultured cell lines Yoshida ascites sarcoma, L-1210 mouse leukemia, OAT cell line derived from human lung cancer of the oat cell type, and P3HR-1 cell line derived from Burkitt's lymphoma have been used for the cell-killing kinetics study of anticancer agents and evaluation of the sensitivity of cells using the soft agar cloning assay method. It has been found that there are 2 types of actions: 1) Type I (cytocidal and concentration-dependent action). The dose survival curves of Type I agents fit the equation log S=log nminuskD (S, surviving fraction; D, concentration of agents; n and k are constant). The sensitivity of cells can be expressed by mean lethal dose 90% (MLD90=1/k). Four cell lines were compared on this basis, and some problems concerning the chemotherapy of human cancer are discussed. Alkylating agents and anticancer antibiotics belonged to this group.2) Type II (cytostatic and time-dependent action). The dose survival curves fit the Gompertz equation S=exp[(minusbeta/alpha)(1minus e-aD)] (beta, population reduction parameter; alpha, constant). The exposure survival curve is negative exponential, indicating that exposure time rather than concentration is the key fo effective cell killing of Type II agents. Difficulties in expression of sensitivity to Type II agents are discussed. Antimetabolites, Vinca alkaloids, and L-asparaginase belonged to this group. The cell-killing kinetics of anticancer agents and comparison of the sensitivity of cells may provide some indications not only of optimal dosage schedules but also of a new approach in screening systems for truly effective agents for human cancer.
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PMID:Cytocidal action of anticancer antigens: evaluation of the sensitivity of cultured animal and human cancer cells. 16 35

L-asparaginase (140,000 units) infused into the hepatic artery resulted in a remission from disabling hypoglycaemia for nine months in a man with islet cell carcinoma of the pancreas and hepatic metastases. The tumour produced insulin and gastrin with resulting hypoglycaemia and recurrent peptic ulceration which were unresponsive to other drugs. Following L-asparaginase there was a fall in both plasma and insulin and gastrin.
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PMID:Prolonged control of hypoglycaemia by L-asparaginase in islet cell carcinoma producing insulin and gastrin. 17 39

The synthesis of L-asparaginase in Escherichia coli W and E. coli K-12 was almost completely supressed if glucose was added at a concentration of 0.5 per cent to a growth medium. The level of L-asparaginase synthesis decreased by ca. 75 per cent as a result of cyamutations when the bacteria could not produce cyclo-3',5'-AMP (cAMP). Apparently, a decrease in the intracellular content of cAMP caused by glucose could not be the only factor inhibiting L-asparaginase synthesis. Lactate was found to stimulate L-asparaginase synthesis. Glucose caused the catabolite repression and catabolite inhibition of the components of a system involved in lactate transport. The inhibition of L-asparaginase synthesis by glucose seems to be due, at least partly, to the fact that it prevents the assimilation of lactate by the cells, as well as the utilization of some other compounds which stimulate synthesis of this enzyme.
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PMID:[Mechanism of action of glucose on L-asparaginase synthesis by Escherichia coli bacteria]. 19 80


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