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 Mg-2plus activated actomyosin ATPase was decreased in the skeletal muscle of the aging rats. At 5 X 10-5M EGTA concentration the inhibition of the Mg-2plus 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 of the 1-month-old animals.
D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000302:isolation & purification / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000375:Aging; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009132:Muscles / Q000032:analysis / Q000201:enzymology / Q000378:metabolism*; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D014335:Tropomyosin / Q000378:metabolism
D000199:Actins; D014335:Tropomyosin; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D009218:Myosins; D008274:Magnesium; D002118:Calcium