EFFECTS OF PH UPON THE LIQUID LIQUID-PHASE EQUILIBRIA IN SOLUTIONS OF LEGUMINS AND VICILINS FROM BROAD BEANS AND PEAS

The effects of pH on the liquid-liquid phase equilibria in solutions of legumins and vicilins from broad beans and peas were investigated. It was shown that for these systems the dependence of solution-critical temperature on pH is at a maximum near the isoelectric point of the protein. This function shifts to the region of lower pH values and temperatures at high concentrations of sodium chloride. The shape of the function is controlled by the balance of dipole-dipole and electrostatic interactions between the protein molecules. Another significant factor of phase equilibria in the systems investigated is the binding of chloride anions with protein molecules which determines the protein isoelectric point.