Urea-induced Recovery of Gelling Ability of Denatured Myosin

Abstract

Myosins from chicken, domestic animals, and fishes were denatured at 80°C for 20min or at 20°C for 30 days in 0.45M KCI-phosphate buffer (pH 7.5). Urea and 2-mercaptoethanol were added to each suspension to achieve the final concentrations of 8M and 0.5%, respectively. The mixture was homogenized at room temperature and left to stand for 30 min. The homogenate was dialyzed overnight at 4°C against water or diluted with water. All the resulting myosin precipitates were more soluble in the above KCI buffer than the denatured myosins. The precipitate obtained by dialysis formed whitish gel on heating at 80°C for 15min in the presence of NaCl. In the case of fishes, the myosin also formed a semi-transparent gel at 40°C for 60min, and the viscosity of its solution increased during heating at 40°C. However, the myosin precipitate obtained by dilution showed neither gel formation nor viscosity increase, but did show some thermoplasticity.