Dissociation and reassociation of enzyme-treated caseins under high pressure

Abstract

Summary: The effects of pressure on the association states of enzyme-treated casein molecules were studied by monitoring the turbidity of the solutions under pressures up to 3000 kg/cm². β-Casein polymers, partly degraded with immobilized trypsin, dissociated with increasing pressure up to a critical pressure (e.g. 1200 kg/cm²) and then reassociated under the higher pressure up to 3000 kg/cm², following a parabolic turbidity-pressure curve. In the case of chymosin-treated κ-casein, a similar pressure dependence of turbidity was found under the same pressure conditions. Based on these results, the pressure effects on dissociation and reassociation of casein molecules were discussed in terms of the volume change of water around their hydrophobic moieties.