Heatーinduced gel forming ability of cardiac myosin and reconstituted actomyosin at different weight ratios was investigated in a model system. Myosin alone always had greater binding power than actomyosin. The "crossーlinking" role of Fーactomyosin does not seem necessary for enhancing the binding strength, at least of cardiac myosin, since the incorporation of actin in different proportion into the myosin system always produced a weaker gel than that formed by myosin alone.
To investigate the smooth muscle, with a view to upgrading the textural qualities of the meat for palatability, we conducted experiments on two actomyosins, YAM (actomyosin extracted by salt solution with PMSF) and BAM (actomyosin extracted by salt solution), from the chicken gizzard. The gelation profiles demonstrated the following properties ; In YAM, two peaks were brought about by the denaturing process, whereas the storage modulus of BAM increased linearly. The differences between the gelation profiles of YAM and BAM are thought to be attributable to the variation of protein composition. The two actomyosins tested are both endowed with gelling capacity, the addition of the divalent metal ion Ca^<2+> or Mg^<2+> enhanced gelation formation considerably.
The increase achieved in the storage modulus in the gizzard actomyosins was commensurated with phosphorylation of the myosin molecules. Consequently, the phosphorylationーelicited changes occurring in the structure of the myosin rod portion were deemed to play a key role in conferring enhanced gelation capabilities on the thermalーtreated actomyosin.