To investigate the effect of high pressure on fish myofibrillar protein, the inactivation of carp myofibrillar Ca-ATPase in the presence and absence of sorbitol was measured.
The results obtained were as follows: 1) The pressure-induced inactivation of myofibrillar Ca-ATPase accelerated with increasing in pressure and in treating time under the pressure. The myofibrillar Ca-ATPase was inactivated almost completely by a pressure of 2.0 kbar at 0°C for 60min. 2) The mode of pressure-induced inactivation was biphasic first order step; a fast early phase followed by a slow phase. 3) The inactivation of myofibrillar Ca-ATPase induced by the pressure was markedly protected by the addition of sorbitol. The protecting effect of sorbitol depended upon the sorbitol concentration, but not on the myofibrillar protein concentra-tion in the system.
The results suggested that sorbitol suppressed the pressure-induced inactivation of myo-fibrillar Ca-ATPase through the change of water structure in the medium.