Enzymatic studies on the skeletal myosin A and actomyosin of aging rats

  • G. Kaldor
  • B. K. Min
Part of the Faseb Monographs book series (FASEBM, volume 3)


Myosin A and actomyosin were isolated from the skeletal muscle of old and young rats. The velocity of the Ca2+ activated myosin A ATPase was increased in the case of the older animals. On the other hand the velocity of the Mg2+ activated actomyosin ATPase was decreased in the skeletal muscle of the aging rats. At 5 × 10−5 m EGTA concentration the inhibition of the Mg2+ activated myosin B ATPase of the 1-month-old rats was two- to threefold smaller than that of the older animals. It was shown that the myosin A component of the actomyosin was responsible for the decreased troponin inhibition in the case of the 1-month-old rats. Between the ages of 1 month and 29 months the number of free myosin A SH groups decreases by 50%. The lipid peroxidation in the muscle tissue of the 29-month-old rats was threefold greater than that in the muscle of the 1-month-old animals. —Kaldor, G., and B. K. Min. Enzymatic studies on the skeletal myosin A and actomyosin of aging rats. Federation Proc. 34: 191–194, 1975.


Enzymatic Study Skeletal Myosin EGTA Concentration Arul Aging Activate ATPase Activity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Michaelis constant


maximal velocity


Energy of activation


Sodium dodecyl sulfate


Ethylene glycol-bis-(ß-aminoethylether)-N, N-tetra acetic acid


inorganic phosphate

µmole Pi mg prot−1 min−1

µmole inorganic phosphate liberated by 1 mg enzyme protein in 1 minute.


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Copyright information

© Federation of American Societies 1975

Authors and Affiliations

  • G. Kaldor
    • 1
  • B. K. Min
    • 1
  1. 1.Department of Physiology and BiophysicsThe Medical College of PennsylvaniaPhiladelphiaUSA

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