1887

Abstract

Mitochondria isolated from grown with sucrose as the sole source of carbon and energy oxidized citrate and -aconitate at high rates, and showed good respiratory control and high ADP/O ratios. The oxidation of both substrates was inhibited strongly by rotenone but only slightly by malonate. In contrast, isocitrate was oxidized slowly, with poor respiratory control. Treatment with detergent showed that both NAD- and NADP-isocitrate dehydrogenases were situated within the mitochondrial matrix. It thus appeared that the rate of oxidation of exogenous isocitrate was limited by a slow rate of translocation across the inner mitochondrial membrane.

When was grown in an acetate-containing medium, the mitochondrial pellet, prepared by differential centrifugation, catalysed a rapid oxidation of isocitrate and contained a high activity of isocitrate lyase. The oxidation of isocitrate and succinate was strongly inhibited by malonate but only slightly by rotenone. Density-gradient centrifugation revealed that the apparent oxidation of isocitrate by mitochondrial pellets was due to contamination by glyoxysomes. Isocitrate was converted into glyoxylate and succinate in the glyoxysomes, then succinate was translocated across the inner mitochondrial membrane and oxidized by the respiratory chain.

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/content/journal/micro/10.1099/00221287-126-2-297
1981-10-01
2021-07-29
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References

  1. Hall D. O., Greenawalt J. W. 1967; The preparation and biochemical properties of mitochondria from Neurospora crassa. Journal of General Microbiology 48:419–430
    [Google Scholar]
  2. Imai K. 1977; Transport system for citric acid in Proteus vulgaris. Agricultural and Biological Chemistry 41:733–735
    [Google Scholar]
  3. Imai K. 1978; Tricarboxylic acid transport systems in Proteus mirabilis. Journal of General and Applied Microbiology 24:279–285
    [Google Scholar]
  4. Katkocin D. M., Slayman C. W. 1976; Permeability measurements on mitochondria from wild-type and poky strains of Neurospora crassa. Journal of Bacteriology 127:1270–1277
    [Google Scholar]
  5. Kobr M. J., Turian G., Zimmerman E. J. 1965; Changes in enzymes regulating isocitrate breakdown in Neurospora crassa. Archiv für Mikrobiologie 52:169–177
    [Google Scholar]
  6. Kobr M. J., Vanderhaeghe F., Combepine G. 1969; Particulate enzymes of the glyoxylate cycle in Neurospora crassa. Biochemical and Biophysical Research Communications 37:640–645
    [Google Scholar]
  7. Lambowitz A. M., Smith E. W., Slayman C. W. 1972; Oxidative phosphorylation in Neurosporu mitochondria. Journal of Biological Chemistry 247:4859–4865
    [Google Scholar]
  8. Nabeshima S., Tanaka A., Fukui S. 1977; Effect of carbon sources on the level of glyoxylate cycle enzymes in n-alkane-utilizable yeasts. Agricultural and Biological Chemistry 41:275–279
    [Google Scholar]
  9. Robinson B. H., Chappell J. B. 1970; The kinetics of tricarboxylate anion oxidation by rat liver mitochondria in relation to the availability of L-malate. Biochimica et biophysica acta 205:300–303
    [Google Scholar]
  10. Schwitzguébel J. P., Møller I. M., Palmer J. M. 1981; Changes in density of mitochondria and glyoxysomes from Neurospora crassa: a re-evaluation utilizing silica sol gradient centrifugation. Journal of General Microbiology 126:289–295
    [Google Scholar]
  11. Zink M. W. 1967; Regulation of the malic enzyme in Neurospora crassa. Canadian Journal of Microbiology 13:1211–1221
    [Google Scholar]
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