CHANGES IN SHEAR MODULUS, ULTRASTRUCTURE AND SPIN‐SPIN RELAXATION TIMES OF WATER ASSOCIATED WITH HEAT‐INDUCED GELATION OF MYOSIN

Abstract
Gelation of myosin in 0.6M KC1 at pH 7.0 and 6.0 during heating at various temperatures between 25–70°C was quantitatively measured by a simple shear modulus tester devised in our laboratory. Shear modulus data indicated that gelation occurs with a stepwise elevation of temperature from 30–60°C. Heat‐treatment of the protein solution remarkably influenced the structure and water mobility in the system. Myosin gel formed by heating had a micro‐network structure, which was not‐present in the original myosin solution. The myosin gel had a slower value of spin‐spin relaxation time compared to that of the original untreated sample, suggesting that the water mobility in the gel system was somehow restricted. The heat‐induced gelation of myosin may be the result of the development of a three dimensional network structure which holds water in a less mobilized state.