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)

Homogenization of guinea pig liver in isotonic sucrose solution followed by the separation of the subcellular fractions by differential centrifugation releases the liver L-asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) activity into the supernatant fraction. Electron micrographs of the liver L-asparaginase-antibody complexes, precipitated from the clear supernatant phase by addition of L-asparaginase-specific antiserum, show membrane-liek structures and some amorphous material. The attachment of L-asparaginase to the membrane-like structures is indicated by the ferritin-labeled antibody technique. The immunoprecipitates possess low activities of 5'-nucleotidase, alkaline phosphodiesterase I, NADPH cytochrome c reductase, glucose-6-phosphatase, and acid phosphatase. This observation suggests that L-asparaginase found in the liver supernatant fraction is associated with cytomembrane components. Analysis of guinae pig serum L-asparaginase-antibody complexes is polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate gives three distinct protein bands. These bands correspond to heavy and light chains of rabbit immunoglobulins and the L-asparaginase subunits. Analysis of the liver L-asparaginase-antibody complexes by the above procedure shows similar but more diffuse protein bands.
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PMID:Evidence for the association of L-asparaginase with cytomembrane components in the guinea pig liver soluble fraction. 81 93

The ammonium assimilatory enzymes glutamine synthetase (EC 6.3.1.2) and glutamate dehydrogenase (EC 1.4.1.3) were investigated for a possible role in the regulation of asparaginase (EC 3.5.1.1) in a Chlamydomonas species isolated from a marine environment. Cells grown under nitrogen limitation (0.1 millimolar NH(4) (+), NO(3) (-), or l-asparagine) possessed 6 times the asparaginase activity and approximately one-half the protein of cells grown at high nitrogen levels (1.5 to 2.5 millimolar). Biosynthetic glutamine synthetase activity was 1.5 to 1.8 times greater in nitrogen-limited cells than cells grown at high levels of the three nitrogen sources.Conversely, glutamate dehydrogenase (both NADH- and NADPH-dependent activities) was greatest in cells grown at high levels of asparagine or ammonium, while nitrate-grown cells possessed little activity at all concentrations employed. For all three nitrogen sources, glutamate dehydrogenase activity was correlated to the residual ammonium concentration of the media after growth (r = 0.88 and 0.94 for NADH- and NADPH-dependent activities, respectively).These results suggest that glutamate dehydrogenase is regulated in response to ambient ammonium levels via a mechanism distinct from asparaginase or glutamine synthetase. Glutamine synthetase and asparaginase, apparently repressed by high levels of all three nitrogen sources, are perhaps regulated by a common mechanism responding to intracellular nitrogen depletion, as evidenced by low cellular protein content.
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PMID:Regulation of asparaginase, glutamine synthetase, and glutamate dehydrogenase in response to medium nitrogen concentrations in a euryhaline chlamydomonas species. 1666 9