[Structural and functional changes in myosin from rat skeletal muscles during postmortem autolysis].

Structure and enzymatic properties of myosin were studied in rat skeletal muscles during various periods of postmortal autolysis. Ca2+-ATPase activity of the protein was decreased within 3 hrs after death. At the same time, the structure of myosin, as shown by gel filtration in 8 M urea and disc electrophoresis in SDS polyacrylamide gel, was maintained. The phenomenon of "substrate inhibition" exhibited both native myosin and the protein isolated from the autolyzed muscle tissue. Enzymatic activity of myosin was markedly decreased within 12 hrs and 24 hrs after death. Degradation of the protein heavy chains was also observed.