1887

Abstract

Measurements were made of the rate of intracellular protein turnover in var. , using two methods. Incorporation of O into protein from H O-enriched medium occurred at linear rates in both autotrophically growing and nitrogen-starved cells. On the assumption that the only port of O incorporation is via the hydrolytic cleavage of peptide bonds followed by resynthesis of the labelled amino acids into new protein, apparent turnover rates were between 1.2 and 2·13% h in growing cells, falling to 0·5% h at the commencement of starvation. After 17·5 h starvation, the rate rose again to the growing cell value. However, analysis of the exchanges between the acid and amides of aspartate and glutamate in the free pool showed that O can also be incorporated via side-chain exchange, thus causing overestimation of turnover. Labelling of protein by growth in HO followed by selective measurement of the α-carbon tritium has also been used to avoid the problem of isotope reincorporation. However, in growing cells, incorporation continued after washing the cells free of unincorporated tritium. In nitrogen-starved cells, two stability classes were seen, 85% of protein being degraded at 3·47% h, and 15% at 1·11% h. It is suggested that this high rate of turnover results from the exposure of the culture to high levels of radioactivity for long periods, and concluded that neither method alone will yield an absolute value for the rate of protein turnover, but differences between classes of protein with different decay rates will be apparent.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-121-1-49
1980-11-01
2024-04-25
Loading full text...

Full text loading...

/deliver/fulltext/micro/121/1/mic-121-1-49.html?itemId=/content/journal/micro/10.1099/00221287-121-1-49&mimeType=html&fmt=ahah

References

  1. Bernlohr R.W. 1972; 18O probes of protein turnover, amino acid transport, and protein synthesis in Bacillus licheniformis. Journal of Biological Chemistry 247:4893–4899
    [Google Scholar]
  2. Bernstein E. 1960; Synchronous division in Chlamydomonas moewusii. Science 131:1528–1529
    [Google Scholar]
  3. Bernt E., Bergmeyer H.-U. 1963 In Methods of Enzymatic Analysis pp. 384–391 Edited by Bergmeyer H.-U. New York: Academic Press.;
    [Google Scholar]
  4. Borek E., Ponticorvo D., Rittenberg D. 1958; Protein turnover in microorganisms. Proceedings of the National Academy of Sciences of the United States of America 44:369–374
    [Google Scholar]
  5. Chandorkar K.R., Szachrajuk R.B., Clark G.M. 1978; Effect of extremely low radiation dosages on synchronised cultures of Chlorella pyrenoidosa. Health Physics 34:495–499
    [Google Scholar]
  6. Davies D.D., Humphrey T.J. 1978; Amino acid recycling in relation to protein turnover. Plant Physiology 61:54–58
    [Google Scholar]
  7. Donald A.S.R. 1973; The products of pronase digestion of purified blood group specific glycoproteins. Biochimica et biophysica acta 317:420–436
    [Google Scholar]
  8. Fensom A.H., Pirt S.J. 1975; Protein turnover measured by 18O exchange with H218O in nongrowing cells of Agrobacterium tumefaciens. Journal of General Microbiology 87:159–162
    [Google Scholar]
  9. Fowden L. 1951; The composition of the bulk protein of Chlorella. Biochemical Journal 50:355–358
    [Google Scholar]
  10. Goldberg A.L., Dice J.F. 1974; Intracellular protein degradation in mammalian and bacterial cells. Annual Review of Biochemistry 43:835–869
    [Google Scholar]
  11. Goldberg A.L., St John A.C. 1976; Intracellular protein degradation in mammalian and bacterial cells, Part II. Annual Review of Biochemistry 45:747–803
    [Google Scholar]
  12. Halvorson H.O. 1958; Studies on protein and nucleic acid turnover in growing cultures of yeast. Biochimica et biophysica acta 27:267–276
    [Google Scholar]
  13. Humphrey T.J., Davies D.D. 1975; A new method for the measurement of protein turnover. Biochemical Journal 148:119–127
    [Google Scholar]
  14. Humphrey T.J., Davies D.D. 1976; A sensitive method for the measurement of protein turnover based on the measurement of 2-3H-amino acids in protein. Biochemical Journal 156:561–568
    [Google Scholar]
  15. Mandelstam J. 1960; The intracellular turnover of protein and nucleic acids, and its role in biochemical differentiation. Bacteriological Reviews 24:289–308
    [Google Scholar]
  16. Märkl H. 1976; Hydrodynamic stress capacity of microorganisms (experiments with algae). Abstracts of the 5th International Fermentation Symposium p. 79 Edited by Dellweg H. Berlin: Westkreuz-Druckerei und Verlag.;
    [Google Scholar]
  17. Morris J. 1966; Inhibition of protein synthesis by cycloheximide (actidione) in Chlorella. Nature; London: 2111190–1192
    [Google Scholar]
  18. Pfleiderer G. 1963 In Methods of Enzymatic Analysis pp. 381–383 Bergmeyer H.-U. New York: Academic Press.;
    [Google Scholar]
  19. Richards L. 1978 Measurement of intracellular protein turnover in the green alga Chlorella Ph.D. thesis: University of London;
    [Google Scholar]
  20. Richards L., Thurston C.F. 1980; Uptake of leucine and tyrosine and their intracellular pools in Chlorella fusca var.vacuolata. Journal of General Microbiology 121:39–47
    [Google Scholar]
  21. Roberts R.B., Cowie D.B., Abelson P.H., Bolton E.T., Britten R.J. 1955 In Studies of Biosynthesis in Escherichia coli. Publications of the Carnegie Institution of Washington 607:13–20
    [Google Scholar]
  22. Sasaki T., Abrams B., Horecker B.L. 1975; A fluorometric method for the determination of the tryptophan content of proteins. Analytical Biochemistry 65:396–404
    [Google Scholar]
  23. Smyth D.G. 1967; Techniques in enzymic hydrolysis. Methods in Enzymology 11:214–231
    [Google Scholar]
  24. Steyermark A. 1961; Microdetermination of oxygen. In Quantitative Organic Microanalysis, 2nd edn. pp. 377–409 Edited by Steyermark A. New York: Academic Press;
    [Google Scholar]
  25. Thinh L.V., Griffiths D.J. 1976; Amino acid composition of autotrophic and heterotrophic cultures of the Emerson strain of Chlorella. Plant and Cell Physiology 17:193–196
    [Google Scholar]
  26. Thurston C.F., Richards L. 1980; Protein turnover in Chlorella fusca var.vacuolata: detection of a rapidly degraded class of protein in growing and non-growing cells. Journal of General Microbiology 121:63–68
    [Google Scholar]
  27. Trinci A.P.J., Thurston C.F. 1976; Transition to the non-growing state in eukaryotic microorganisms. Symposia of the Society for General Microbiology 26:58–80
    [Google Scholar]
  28. Udenfriend S., Stein S., Bohlen P., Dairman W., Leimgruber W., Weigele M. 1972; Fluorescamine: a reagent for assay of amino acids, peptides, proteins and primary amines in the picomole range. Science 178:871–872
    [Google Scholar]
  29. Unterzaucher J. 1951; Elementary determination of oxygen. A method of determining carbon and hydrogen developed from it, and a new procedure for carrying out the Dumas nitrogen determination for compounds difficult to burn. Mikrochemie vereinigt mit Mikrochemica acta 36/37:706–726
    [Google Scholar]
  30. Unterzaucher J. 1952; The direct microdetermination of oxygen in organic substances. Analyst 77:584–595
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-121-1-49
Loading
/content/journal/micro/10.1099/00221287-121-1-49
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error