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Metabolism of myofibrillar proteins in the normal and hypertrophic heart

Conference paper

Summary

The pathways of myofibrillar assembly and degradation were studied in normal heart and during developing hypertrophy by two independent methods: amino acid incorporation kinetics and the double isotope technique.

The validity and sensitivity of both methods were evaluated by computer analysis of data for which leucyl-tRNA was used as a protein precursor.

The data obtained indicate that the myofibrillar proteins turn over at nonuniform rates. The half-lives of the proteins studied increase as follows: myosin HC = α-actin = tropomyosin > LC1 = LC2 > actin. In the case of light chains, a macromolecular precursor pool was detected which contributes to the observed lower labeling with 3H-leucine.

During developing hypertrophy, the rate of light-chain labeling is increased relative to that of heavy chains.

Stoffwechsel der myofibrillären Proteine in normalen und hypertrophierten Herzen

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References

  1. 1.
    Zak, R., M. Rabinowitz: Control of protein synthesis and degradation in normal and work-overloaded cardiac muscle. In Morkin, E. (ed.): Cardiac Hypertrophy. New York, in press.Google Scholar
  2. 2.
    Martin, A. F., M. Rabinowitz, R. Blough, G. Prior, R. Zak: Measurements of the half-life of rat cardiac myosin heavy chains with leucyl-tRNA used as precursor. J. Biol. Chem. (in press).Google Scholar
  3. 3.
    Martin, A. F., G. Prior, R. Zak: Determination of specific radioactivity of amino acids in proteins directly on polyacrylamide gels: an application to 1-leucine. Anal. Biochem. 72, 577 (1976).PubMedCrossRefGoogle Scholar
  4. 4.
    Pool, B.: The kinetics of disappearance of labeled leucine from the free leucine pool of rat liver and its effects on the apparent turnover of catalase and other hepatic proteins. J. Biol. Chem. 246, 6587 (1971).Google Scholar
  5. 5.
    Zak, R., A. F. Martin, G. Prior, M. Rabinowitz, R. Blough: Comparison of turnover of several myofibrillar proteins and critical evaluation of the double isotope method. J. Biol. Chem. (in press).Google Scholar
  6. 6.
    Funabiki, R., R. G. Cassens: Heterogeneous turnover of myofibrillar proteins. Nature 236, 249 (1972).CrossRefGoogle Scholar
  7. 7.
    Low, R. B., A. L. Goldberg: Nonuniform rates of turnover of myofibrillar proteins in rat diaphragm. J. Cell. Biol. 56, 590 (1973).PubMedCrossRefGoogle Scholar
  8. 8.
    Koizumi, T.: Turnover rates of structural proteins of rabbit skeletal muscle. J. Biochem. 76, 431 (1974).PubMedGoogle Scholar
  9. 9.
    Zak, R., E. Rakitzis, M. Rabinowitz: Evidence for simultaneous turnover of four cardiac myofibrillar proteins. Fed. Proc. 30, 1147 (Abstr.) (1971).Google Scholar
  10. 10.
    Etlinger, J. D., R. Zak, D. A. Fischman, M. Rabinowitz: Isolation of newly synthesized myosin filaments from skeletal muscle homogenates and myofibrils. Nature 255, 259 (1975).PubMedCrossRefGoogle Scholar

Copyright information

© Dr. Dietrich Steinkopff Verlag, Darmstadt 1977

Authors and Affiliations

  • R. Zak
    • 1
    • 2
  1. 1.Cardiology Section of the Department of MedicineThe University of Chicago, and the Franklin McLean Memorial Research InstituteChicagoUSA
  2. 2.Department of MedicineThe University of ChicagoChicagoUSA

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