Observation of Transmitted Light Spectra during Gelation Process of Actomyosin

The heat-induced gelation process of muscle protein, actomyosin, was investigated by observing the transmitted light spectra. First, the temperature characteristic of the gelation (T'g) was determined from the spectral changes, showing remarkable dependence on pH and [NaCl]. Moreover, the spectra varied drastically with time after the temperature-jump procedure. From the time dependence of the observed spectra, the turbidity was calculated to characterize the light-scattering properties. The logarithm of the turbidity showed approximately linear dependence on the logarithm of the wavelength, and the slope increased with time, suggesting the growth of the actomyosin assembly during the gelation process.