DYNAMIC RHEOLOGICAL BEHAVIOR AND BIOCHEMICAL-PROPERTIES OF RABBIT SKELETAL ACTOMYOSIN DURING STORAGE AT 0-DEGREES-C

The relationship between the dynamic theological properties of heat-in duced gels of actomyosin (natural actomyosin) and the denaturation of actin in actomyosin during storage without ATP at pH 6.0 and 0 degrees C was investigated using biochemical and dynamic theological measurem ents. The complex modulus of gels after heating actomyosin containing 0.5 or 1.5 M KCl (pH 6.0) at 80 degrees C increased with increasing st orage time. The dynamic theological behaviour during heat gelation of actomyosin in 1.5 M KCl indicated that the first theological transitio n peak in the 50-53 degrees C range induced by the presence of F-actin gradually disappeared with increasing storage time. However, in 0.5 M KCl, this transition peak clearly remained even after 15 days. The ti me course of denaturation of actin in actomyosin treated with 1.5 M KC l at pH 6.0 showed an increase in the percent denaturation after the s torage was started, and about 100% of the actin became denatured after 21 days. In the case of 0.5 M KCl, unlike 1.5 M, the denaturation of actin occurred quickly within the first 5 days and then did not procee d. A sigmoidal relationship was found between the percent denaturation of actin and the KCl concentration added, the greatest change occurri ng at KCl concentrations between 0.5 and 1.0 M. The data indicated tha t the change in the property of actin in actomyosin during storage at low temperature exerts a great influence on the viscoelasticity of hea t-induced gels of actomyosin.