Elevated levels of a calcium-activated muscle protease in rapidly atrophying muscles from vitamin E-deficient rabbits

William R. Dayton, Judith V. Schollmeyer, Alvin C. Chan, C. Eugene Allen

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56 Scopus citations

Abstract

A Ca2+-activated proteolytic enzyme * that partially degrades myofibrials was isolated from hind limb muscles of normal rabbits and rabbits undergoing rapid muscle atrophy as a result of vitamin E deficiency. Extractable Ca2+-activated protease activity was 3.6 times higher in muscle tissue from vitamin E-deficient rabbits than from muscle tissue of control rabbits. Ultrastructural studies of muscle from vitamin E-deficient rabbits showed that the Z disk was the first myofibrillar structure to show degradative changes in atrophying muscle. Myofibris prepared from muscles vitamin E-deficient rabbits showed partial or complete loss of Z-disk density. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the amount of troponin-T (37 000 daltons) and α-actinin (96 000 daltons) was reduced in myofibrils from atrophying muscle as compared to myofibrils prepared from control muscle. In vitro treatment of purified myofibrils with purified Ca2+-activated proteolytic enzyme produced alterations in myofibrillar ultrastructure that were identical to the initial alterations occuring in myofibrils from atrophying muscle (i.e. weakening and subsequent removal of Z disks). Additionally the electrophoretic banding pattern of Ca2+-activated proteolytic enzyme-treated myofibrils is very similar to that of myofibrils prepared from muscles atrophying as a result of nutritional vitamin E deficiency. The possible role of Ca2+-activated proteolytic enzyme in disassembly and degradation of the myofibril is discussed.

Original languageEnglish (US)
Pages (from-to)216-230
Number of pages15
JournalBBA - General Subjects
Volume584
Issue number2
DOIs
StatePublished - May 2 1979

Bibliographical note

Funding Information:
This work was supported by a grant from the University of Minnesota Graduate School and by a grant from the Minnesota Heart Association. This is Scientific Journal Series Paper No. 10 670, Minnesota Agricultural Experiment Station, University of Minnesota, St. Paul, MN 55108, U.S.A.

Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.

Keywords

  • (Rabbit muscle)
  • Ca activation
  • Myofibril
  • Protease
  • Vitamin E

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