Oxidative Modification of Glutamine Synthetase: Covalent and Conformational Changes Which Control Susceptibility to Proteolysis

  • Rodney L. Levine
  • A. Jennifer Rivett
Part of the Basic Life Sciences book series (BLSC, volume 49)


Mixed function oxidation of proteins has been implicated in a variety of physiologic and pathologic processes, including intracellular protein turnover, host defense activities, oxygen toxicity, and the aging process. Many key enzymes are susceptible to oxidative modification, usually with loss of catalytic activity.1 Glutamine synthetase from Escherichia coli is oxidatively modified by a number of enzymic and non-enzymic mixed function oxidation systems.2,3 To understand the effects of oxidative modification, we have studied the covalent and non-covalent changes in glutamine synthetase which occur upon oxidative modification. Protein of varying extent of modification was prepared by timed exposure to a model system consisting of ascorbate, iron, and molecular oxygen.1,4 These modified proteins were analyzed for several covalent and conformational changes. We were particularly interested in identifying changes which correlate with increased susceptibility to proteolysis by a novel high molecular weight protease purified from rat liver.


Glutamine Synthetase Histidine Residue Sedimentation Velocity Oxidative Modification Cation Binding Site 


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  1. 1.
    L. Fucci, C. N. Oliver, M. F. Coon, and E. R. Stadtman, Inactivation of key metabolic enzymes by mixed-function oxidation reactions: Possible implication in protein turnover and aging, Proc. Natl. Acad. Sci. U.S.A. 80:1521 (1983).PubMedCrossRefGoogle Scholar
  2. 2.
    R. L. Levine, C. N. Oliver, R. M. Fulks, and E. R. Stadtman, Turnover of bacterial glutamine synthetase: Oxidative inactivation precedes proteolysis, Proc. Natl. Acad. Sci. U.S.A. 78:2120 (1981).PubMedCrossRefGoogle Scholar
  3. 3.
    E. R. Stadtman and M. E. Wittenberger, Inactivation of Escherichia coli glutamine synthetase by xanthine oxidase, nicotinate hydroxylase, horseradish peroxidase, or glucose oxidase: Effects of ferredoxin, putidaredoxin, and menadione, Arch. Biochem. Biophys. 239:379 (1985).CrossRefGoogle Scholar
  4. 4.
    R. L. Levine, Oxidative modification of glutamine synthetase. II. Characterization of the ascorbate model system, J. Biol. Chem. 258:11828 (1983).PubMedGoogle Scholar
  5. 5.
    A. J. Rivett, Purification of a liver alkaline protease which degrades oxidatively modified glutamine synthetase. Characterization as a high molecular weight cysteine protease, J. Biol. Chem. 260:12600 (1985).PubMedGoogle Scholar
  6. 6.
    R. L. Levine, Oxidative modification of glutamine synthetase. I. Inactivation is due to loss of one histidine residue, J. Biol. Chem. 258:11823 (1983).PubMedGoogle Scholar
  7. 7.
    J. M. Farber and R. L. Levine, Sequence of a peptide susceptible to mixed-function oxidation: Probable cation binding site in glutamine synthetase, J. Biol. Chem. 261:4574 (1986).PubMedGoogle Scholar
  8. 8.
    R. J. Almassy, C. A. Janson, R. Hamlin, N.-H. Xuong, and D. Eisenberg, Novel subunit-subunit interactions in the structure of glutamine synthetase, Nature 323:304 (1986).PubMedCrossRefGoogle Scholar
  9. 9.
    E. R. Stadtman and A. Ginsburg, The glutamine synthetase of Escherichia coli: Structure and control, in: “The Enzymes,” P. D. Boyer, ed., Academic Press, New York (1974).CrossRefGoogle Scholar
  10. 10.
    A. J. Rivett and J. F. Hare, Mixed-function oxidation of glutamine synthetase leads to its rapid degradation in vitro and after fusion-mediated injection into hepatoma cells, Biochem. Soc. Trans. 14:643 (1986).Google Scholar
  11. 11.
    A. J. Rivett, Regulation of intracellular protein turnover: Covalent modification as a mechanism of marking proteins for degradation, Curr. Top. Cell Regul. 28:291 (1986).PubMedGoogle Scholar
  12. 12.
    J. E. Roseman and R. L. Levine, Purification of a protease from Escherichia coli with specificity for oxidized glutamine synthetase, J. Biol. Chem. 262:2101 (1987).PubMedGoogle Scholar
  13. 13.
    A. J. Rivett, Preferential degradation of the oxidatively modified form of glutamine synthetase by intracellular mammalian proteases, J. Biol. Chem. 260:300 (1985).PubMedGoogle Scholar

Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • Rodney L. Levine
    • 1
  • A. Jennifer Rivett
    • 2
  1. 1.Laboratory of BiochemistryNational Heart, Lung, and Blood InstituteBethesdaUSA
  2. 2.Department of BiochemistryUniversity of LeicesterLeicesterUK

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