Enzymatic studies on the skeletal myosin A and actomyosin of aging rats
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.
KeywordsEnzymatic Study Skeletal Myosin EGTA Concentration Arul Aging Activate ATPase Activity
Energy of activation
Sodium dodecyl sulfate
Ethylene glycol-bis-(ß-aminoethylether)-N, N-tetra acetic acid
- µmole Pi mg prot−1 min−1
µmole inorganic phosphate liberated by 1 mg enzyme protein in 1 minute.
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