Physicochemical Properties and Heat-induced Gelling of Cardiac Myosin in Model System

Some physicochemical and functional properties of cardiac myosin were studied in a model system, with particular reference to its binding ability in re-structured meat. We found that myosin solubility was strongly influenced by the pH, ionic strength, and temperature of the system and by the interaction of pH and ionic strength. For instance, myosin remained completely in solution in monomeric form at ionic strengths ≤0.2 M KCl, if the pH of system was maintained at 7.0. Highionic strength was required to keep myosin in monomeric form at low pH. With low ionic strength and pH, myosin molecules tend to form aggregated filaments. Like skeletal muscle myosin, the heat-induced gel strength of cardiac myosin was also influenced by the pH, ionic strength, and temperature of the system, and it produced a gel with maximum strength (21.× 103dyn/cm2) at pH 5.5 and 0.1 M KCl concentration on heating to 60%C. Cardiac myosin seems to form much stronger gels than skeletal muscle myosin.