1887

Abstract

SUMMARY: H production by nitrogenase was investigated in O-, N-, C- or SO -limited continuous cultures of . H evolution occurred under air and was augmented when Ar replaced N. Pretreatment of each culture with 40% acetylene in air or Ar/O mixtures inhibited the H-uptake hydrogenase and increased H evolution. H production in each culture was O-dependent, and, like acetylene reduction by nitrogenase, it increased to a maximum at an optimum O concentration and was inhibited by excess O. The molar ratio of H produced to N reduced was least at the optimum O concentration and increased sharply under O-limiting or O-inhibiting conditions in vivo. The minimum value achieved was approximately 1 in O-, N- or C-limited cultures, or with purified nitrogenase components assayed in vitro, and 0·5 in SO -limited cultures. These differences may reflect different mechanisms of N reduction in vivo. Estimates of the levels of nitrogenase component proteins indicated Ac1: Ac2 ratios of 1 or less. However, Ac2 activity may be inhibited under O-limiting or O-inhibiting conditions. The maximum ratio of the number of electrons transferred to nitrogenase and to O was 0·1 in assays with O-, C- or SO -limited cultures; thus, recycling by the H-uptake hydrogenase of H produced by nitrogenase could contribute up to 7% of the total energy produced by respiration.

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1981-06-01
2024-12-10
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References

  1. Andersen K., Shanmugam K.T. 1977; Energetics of biological nitrogen fixation: determination of the ratio of formation of H2 to NH4 +catalysed by nitrogenase of Klebsiella pneumoniae in vivo. Journal of General Microbiology 103:107–122
    [Google Scholar]
  2. Baker K. 1968; Low cost continuous culture apparatus. Laboratory Practice 17:817–824
    [Google Scholar]
  3. Baker K. 1978; Design, construction, and operation of some all-glass pilot-plant fermentors. Biotechnology and Bioengineering 20:1345–1375
    [Google Scholar]
  4. Bulen W.A. 1976; Nitrogenase from Azotobacter vinelandii and reactions affecting mechanistic interpretations. In Proceedings of the First International Symposium on Nitrogen Fixation 1 pp. 177–195 Newton W.E., Nymans C. Edited by Pullman, Washington:: Washington State University Press.;
    [Google Scholar]
  5. Burns R.C., Bulen W.A. 1965; ATP-dependent hydrogen evolution by cell-free preparations of Azotobacter vinelandii. Biochimica et biophysica acta 105:437–445
    [Google Scholar]
  6. Burns R.C., Hardy R.W.F. 1975 Nitrogen Fixation in Bacteria .and Higher Plants. Berlin:: Springer-Verlag.;
    [Google Scholar]
  7. Chatt J. 1980; Chemistry relevant to the biological fixation of nitrogen. In Nitrogen Fixation Annual Proceedings of the Phytochemical Society of Europe 18 pp. 1–18 Stewart W.D.P., Gallon J.R. Edited by London:: Academic Press.;
    [Google Scholar]
  8. Dalton H., Postgate J.R. 1969; Growth and physiology of Azotobacter chroococcum in continuous culture. Journal of General Microbiology 56:307–319
    [Google Scholar]
  9. Eady R.R., Smith B.E., Cook K.A., Postgate J.R. 1972; Nitrogenase of Klebsiella pneumoniae. Biochemical Journal 128:655–675
    [Google Scholar]
  10. Evans H.J., Ruiz-ArgÜeso T., Jennings N., Hanus J. 1977; Energy coupling efficiency of symbiotic nitrogen fixation. In Genetic Engineering for Nitrogen Fixation pp. 333–354 Hollaender A. Edited by New York:: Plenum Press.;
    [Google Scholar]
  11. Haaker H., Dekok A., Veeger C. 1974; Regulation of dinitrogen fixation in intact Azotobacter vinelandii. Biochimica et biophysica acta 357:344–357
    [Google Scholar]
  12. Hoch G.E., Little H.N., Burris R.H. 1957; Hydrogen evolution from soy-bean root nodules. Nature; London: 179430–431
    [Google Scholar]
  13. Hoch G.E., Schneider K.C., Burris R.H. 1960; Hydrogen evolution and exchange and conversion of NzO to N2 by soybean root nodules. Biochimica et biophysica acta 37:273–279
    [Google Scholar]
  14. Kennedy C., Eady R.R., Kondorosi E., Rekosh D.K. 1976; The molybdenum-iron protein of Klebsiella pneumoniae nitrogenase: evidence for non-identical subunits from peptide ‘mapping’. Biochemical Journal 155:383–389
    [Google Scholar]
  15. Laemmli U.K. 1970; Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature; London: 227680–685
    [Google Scholar]
  16. Maier R.J., Postgate J.R., Evans H.J. 1978; Rhizobium japonicum mutants unable to use hydrogen. Nature; London: 276494–495
    [Google Scholar]
  17. Maryan P.S., Vorley W.T. 1979; An improved spectrophotometric method for the determination of ammonia with particular relevance to in vitro nitrogenase activity. Laboratory Practice 28:251–252
    [Google Scholar]
  18. Mortensen L.E., Thorneley R.N.F. 1979; Structure and function of nitrogenase. Annual Review of Biochemistry 48:387–418
    [Google Scholar]
  19. Newton W.E., Bulen W.A., Hadfield K.L., Stiefel E.I., Watt G.D. 1977; HD formation as a probe for intermediates in N2 reduction. In Recent Developments in Nitrogen Fixation pp. 119–130 Newton W.E., Postgate J.R., Rodriguez-Barrueco C. Edited by London:: Academic Press.;
    [Google Scholar]
  20. Partridge C.D.P., Walker C.C., Yates M.G., Postgate J.R. 1980; The relationship between hydrogenase and nitrogenase in Azotobacter chroococcum: effect of nitrogen sources on hydrogenase activity. Journal of General Microbiology 119:313–319
    [Google Scholar]
  21. Postgate J.R. 1974; Prerequisites for biological nitrogen fixation in free-living heterotrophic bacteria. In The Biology of Nitrogen Fixation pp. 663–686 Quispel A. Edited by Amsterdam:: North Holland.;
    [Google Scholar]
  22. Robson R.L. 1979a; O2-repression of nitrogenase synthesis in Azotobacter chroococcum. FEMS Microbiology Letters 5:259–262
    [Google Scholar]
  23. Robson R.L. 1979b; Characterisation of an oxygen-stable nitrogenase complex isolated from Azotobacter chroococcum. Biochemical Journal 181:569–575
    [Google Scholar]
  24. Scherings G., Haaker H., Veeger C. 1977; Regulation of nitrogen fixation by Fe-S protein II in Azotobacter vinelandii. European Journal of Biochemistry 77:1207–1211
    [Google Scholar]
  25. Schrauzer G.N. 1977; Nitrogenase model systems and the mechanism of biological nitrogen reduction: advances since 1974. In Recent Developments in Nitrogen Fixation pp. 109–118 Newton W., Postgate J.R, Rodriguez-Barrueco C. Edited by London:: Academic Press.;
    [Google Scholar]
  26. Schubert K.R., Evans H.J. 1976; Hydrogen evolution: a major factor affecting the efficiency of nitrogen fixation in nodulated symbionts. Proceedings of the National Academy of Sciences of the United States of America 73:1207–1211
    [Google Scholar]
  27. Shah V.K., Davis L.C., Brill W.J. 1975; Nitrogenase. VI. Acetylene reduction assay: dependence of nitrogen fixation estimates on component ratio and acetylene concentration. Biochimica et biophysica acta 384:353–359
    [Google Scholar]
  28. Silverstein R., Bulen W.A. 1970; Kinetic studies of the nitrogenase-catalyzed hydrogen evolution and nitrogen reduction reactions. Biochemistry 9:3809–3815
    [Google Scholar]
  29. Smith L.A., Hill S., Yates M.G. 1976; Inhibition by acetylene of conventional hydrogenase in nitrogen-fixing bacteria. Nature; London: 262209–210
    [Google Scholar]
  30. Thorneley R.N.F., Eady R.R. 1977; Nitrogenase of Klebsiella pneumoniae: distinction between proton-reducing and acetylene-reducing forms of the enzyme. Biochemical Journal 167:457–461
    [Google Scholar]
  31. Thorneley R.N.F., Eady R.R., Lowe D.J. 1978; Biological nitrogen fixation by way of an enzyme-bound dinitrogen-hydride intermediate. Nature; London: 272557–558
    [Google Scholar]
  32. Walker C.C., Yates M.G. 1978; The hydrogen cycle in nitrogen-fixing Azotobacter chroococcum. Biochimie 60:225–231
    [Google Scholar]
  33. Yates M.G., PlanquÉ K. 1975; Nitrogenase from Azotobacter chroococcum. Purification and properties of the component proteins. European Journal of Biochemistry 60:467–476
    [Google Scholar]
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