Hydrolysis of α-lactalbumin by chymosin and pepsin. Effect of conformation and pH

The correlation between change of conformation of a-Iactalbumin and its degradation by gastric enzymes was verified.With citrate buffer (0.1 M), the modification of a-Iactalbumin conformation occurred when the pH value was below pH 4.0.This conformational change was influenced by buffer composition and ionic strength.However, the presence of EDTA in the butter did not modify the pH value at which the change of conformation of the protein occurred.Concomitantly, hydrolysis of a-Iactalbumin by bovine and porcine pepsins A and rennet was observed at pH values corresponding to the change in conformation of the protein.However, with chymosin, under the same pH and ionie strength conditions there was no significant hydrolysis of a-Iactalbumin.