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)

A high L-asparaginase (L-asparagine amidohydrolase: EC 3.5.1.1) activity was found under conditions of lysine overproduction in cultures of Corynebacterium glutamicum. L-Asparaginase was purified 98-fold by protamine sulphate precipitation. DEAE-Sephacel anion exchange, ammonium sulphate precipitation and Sephacryl S-200 gel filtration. The asparaginase protein was subjected to PAGE under non-denaturing conditions, identified by an in situ reaction and eluted from the gel in an active form. The estimated Mr from gel filtration and SDS-PAGE was 80,000. The L-asparaginase activity was inhibited by the L-asparagine analogue 5-diazo-4-oxo-L-norvaline. Neither D-asparagine nor L-glutamine was a substrate for the enzyme. L-Asparaginase was produced constitutively: its role may be that of an overflow enzyme, converting excess asparagine into aspartic acid, the direct precursor of lysine and threonine.
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PMID:Characterization and partial purification of L-asparaginase from Corynebacterium glutamicum. 239 90

Staphylococcal L-asparaginase has been purified 400-fold with 40% recovery. The procedure involves ammonium sulphate precipitation and a column chromatography on Sephadex G-200 gel filtration). The enzyme is composed of not identical subunits. protein (pI 4.4) with the approximate molecular weight of 125,000 (estimated by Sephadex G-200 gel filtration). The enzyme is composed of not identical subunits. The polyacrylamide-SDS gel electrophoresis indicated two subunits with molecular weight 18,000 and 22,000.
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PMID:Staphylococcal L-asparaginase: purification and properties of enzymic protein. 248 41

Photo-switchable ion and enzyme sensors were fabricated by the use of glassy carbon electrode coated with nonactindoped or enzyme modified poly(vinyl chloride) (PVC) membranes. The ion sensor with nonactin-doped PVC membrane, which contained spirobenzopyran as the photosensitive dye, exhibited a potentiometric photoresponse to NH4+ ion in the solution. The dynamic range of the NH4+ ion sensor was 10(-7)--10(-3) M. Urea, adenosine, and asparagine sensors were prepared by coating the surface of the NH4+-ion sensor with urease, adenosine deaminase, and asparaginase membranes, respectively. These enzyme sensors could be used for determining the substrates at the micro mole level. The performance characteristics of these sensors were compared with those previously prepared membrane electrode sensors.
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PMID:Photo-switchable ion and enzyme sensors. Photoinduced potentiometric response of glassy carbon electrode coated with polymer or polymer/enzyme dual membrane. 263 77

Crystals of an L-asparaginase from Vibrio succinogenes were obtained with the hanging drop method from ammonium sulphate-containing solutions. The crystals belong to the orthorhombic space group P22(1)2(1) with unit cell dimensions of a = 71.3 A, b = 85.8 A, c = 114.0 A, and contain two tetrameric enzyme molecules per unit cell. There are two subunits in the asymmetric unit; a molecular dyad is coincident with the crystallographic dyad. The crystal lattice is similar to that reported for an Escherichia coli asparaginase. Rotation function calculations have revealed that the V. succinogenes enzyme has 222 point group symmetry in the crystal. The second and third molecular dyads differ, however, from the corresponding E. coli asparaginase dyads by approximately 40 degrees. The crystals diffract to at least 2.2 A resolution and are suitable for X-ray crystallographic structure determination.
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PMID:Preliminary crystallographic study of an L-asparaginase from Vibrio succinogenes. 403 77

In a series of 40 patients treated with L-asparaginase for various neoplastic diseases, 6 patients had generalized anaphylactic reactions to L-asparaginase. Each of these reactors had antibodies detectable by passive hemagglutination, but precipitins were detectable in only one of this group of six patients. That patient had received two courses of the enzyme. 1 wk after the anaphylactic reaction, complement-fixing antibodies were present in all the patients that were studied. Specific reagin antibodies (IgE) were demonstrated in one patient by the release of histamine from his leukocytes after incubation in vitro with L-asparaginase. Binding of L-asparaginase to serum antibodies after incubation in vitro was detected by selective precipitation of the complexes with 30% ammonium sulfate or by ultracentrifugation. Total inactivation of the enzyme did not occur even at optimal proportions or at antibody excess. Passive hemagglutinating antibodies to L-asparaginase were present in all patients who had an allergic reaction at least 1 day before the reaction occurred, when that sample was available, and were absent in all patients who did not manifest clinical allergy. Titration of antibodies by passive hemagglutination may thus provide a means of predicting impending anaphylaxis in this system, particularly when coupled with a sudden decrease in circulating levels of L-asparaginase activity.
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PMID:Immunological responses to L-asparaginase. 410 90

Of 28 coliforms, five strains of Escherichia coli were particularly active in elaborating L-asparaginase 2, the form of the enzyme useful in the treatment of some forms of cancer. Since it is advantageous to start purification of the enzyme from highly active cells, cultural conditions necessary for good growth and high enzyme yield have been studied. Gentle aeration proved suitable for good growth as well as high enzyme content. Stationary cultures gave poor growth, whereas vigorous aeration gave good growth but resulted in a marked decrease in the enzyme content of the cells. L-Asparaginase 2 has been purified about 40-fold by a combination of ammonium sulfate and ethyl alcohol precipitations.
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PMID:Conditions for the production of L-asparaginase 2 by coliform bacteria. 490 96

To produce an immunologically and enzymologically new type of l-asparaginase, 108 strains of bacteria were screened for enzyme production. As a result, 13 bacteria belonging to the genera Alcaligenes, Bacterium, and Proteus were found to produce l-asparaginases in high levels. Among these l-asparaginases, partially purified l-asparaginases from B. cadaveris and P. vulgaris showed antitumor activity. A partially purified l-asparaginase preparation of P. vulgaris did not react with the antibody of Escherichia colil-asparaginase on the Ouchterlony agar plate. Culture conditions for the production of l-asparaginase by P. vulgaris were investigated in detail. The enzyme was produced in high yields when cells were grown aerobically in a medium containing sodium fumarate and corn steep liquor. The addition of glucose or ammonium ion to the medium, however, resulted in depressed production of l-asparaginase. Under the optimum conditions, 3,700 international units of l-asparaginase was obtained from 1 liter of culture medium.
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PMID:L-Asparaginase from Proteus vulgaris. 500 Aug 66

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-ketoglutarate and a concomitant inability to equilibrate ammonium ion with alpha-amino nitrogen. In the glutamate auxotroph, asparaginase II biosynthesis exhibited a decreased sensitivity to nitrogen catabolite repression by ammonium ion but normal sensitivity to nitrogen catabolite repression by all amino acids tested.
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PMID:Nitrogen catabolite repression in a glutamate auxotroph of Saccharomyces cerevisiae. 612

We isolated pleiotropic mutants of Klebsiella aerogenes with the transposon Tn5 which were unable to utilize a variety of poor sources of nitrogen. The mutation responsible was shown to be in the asnB gene, one of two genes coding for an asparagine synthetase. Mutations in both asnA and asnB were necessary to produce an asparagine requirement. Assays which could distinguish the two asparagine synthetase activities were developed in strains missing a high-affinity asparaginase. The asnA and asnB genes coded for ammonia-dependent and glutamine-dependent asparagine synthetases, respectively. Asparagine repressed both enzymes. When growth was nitrogen limited, the level of the ammonia-dependent enzyme was low and that of the glutamine-dependent enzyme was high. The reverse was true in a nitrogen-rich (ammonia-containing) medium. Furthermore, mutations in the glnG protein, a regulatory component of the nitrogen assimilatory system, increased the level of the ammonia-dependent enzyme. The glutamine-dependent asparagine synthetase was purified to 95%. It was a tetramer with four equal 57,000-dalton subunits and catalyzed the stoichiometric generation of asparagine, AMP, and inorganic pyrophosphate from aspartate, ATP, and glutamine. High levels of ammonium chloride (50 mM) could replace glutamine. The purified enzyme exhibited a substrate-independent glutaminase activity which was probably an artifact of purification. The tetramer could be dissociated; the monomer possessed the high ammonia-dependent activity and the glutaminase activity, but not the glutamine-dependent activity. In contrast, the purified ammonia-dependent asparagine synthetase, about 40% pure, had a molecular weight of 80,000 and is probably a dimer of identical subunits. Asparagine inhibited both enzymes. Kinetic constants and the effect of pH, substrate, and product analogs were determined. The regulation and biochemistry of the asparagine synthetases prove the hypothesis strongly suggested by the genetic and physiological evidence that a glutamine-dependent enzyme is essential for asparagine synthesis when the nitrogen source is growth rate limiting.
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PMID:Asparagine synthetases of Klebsiella aerogenes: properties and regulation of synthesis. 612 99

In a series of four experiments, asparaginase and glutaminase activity was measured in liver and kidney tissue of 7- to 19-day-old male broiler chicks. In Experiment 1, chicks were fed purified amino acid diets with 14.8 and 44.6% protein equivalents (PE) with 1, 3, or 5% added sodium bicarbonate. In Experiments 2, 3, and 4 the chicks were fed a 23% protein basal control diet, basal diet containing 5% ammonium chloride, and basal diet containing 5% ammonium chloride with 5 or 10% sodium bicarbonate, asparagine, or glutamine. In Experiments 2 and 4 the chicks were also fed 25, 50, or 75% protein-isolated soy-purified diets. The 44.6% PE diet increased liver and kidney asparaginase activity in chicks as compared to chicks fed a 14.8% PE diet. The addition of sodium bicarbonate to the 44.6% PE amino acid diet decreased the kidney asparaginase activity equivalent to kidney asparaginase activity of chicks fed the 14.8% PE diet. Asparaginase activity increased 4-fold in the kidneys of chicks fed the 23% protein basal diet containing 5% ammonium chloride and the pH of the urine from the chicks was 4.9. Chicks fed basal diets with 5% ammonium chloride plus 10% sodium bicarbonate or asparagine had the same kidney asparaginase activity and urine pH as chicks fed the 23% protein basal control diet. Glutamine added to chick diets containing 5% ammonium chloride did not decrease the kidney asparaginase activity or the urine acidity. Liver asparaginase activity was not increased in acidotic chicks fed diets with 5% ammonium chloride. The asparaginase activity of liver and kidney tissue were both significantly increased in chicks fed 75% protein-isolated soy purified diets and the pH of their urine was 5.6. The increase in liver asparaginase of chicks fed 75% protein or 44.5% PE diets was probably due to an endocrine gluconeogenic response producing increased catabolism of the majority of amino acids. The increase in kidney asparaginase of chicks fed 75% protein, 44.5% PE diets, and 23% protein basal diets with 5% ammonium chloride was primarily related to metabolic acidosis. Phosphate-dependent glutaminase (PDG) activity was localized in chick kidney mitochondria and was heat sensitive (55 C for 30 sec). The phosphate-independent glutaminase (PIG) activity was primarily localized in chick kidney mitochondria but was stable to a temperature of 55 C for 30 sec.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Asparagine and glutamine metabolism in chicks. 632 68


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