Heat-induced Aggregation between Ovalbumin and Lysozyme

Abstract

The heat-induced aggregation between ovalbumin and lysozyme was investigated under various conditions by measuring the development of turbidity. The result of sodium dodecylsulfatepolyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol indicated that the obtained aggregate consisted of nearly the same amounts of ovalbumin and lysozyme. The heat-induced aggregation was inhibited by an increase of ionic strength. The effect of chemical modifications (succinylation and carboxymethylation) of the proteins on the heat-induced aggregation was examined to estimate the participation of specific amino acid residues in the aggregation process, the result indicating that the lysine and cysteine residues in the proteins were directly involved. From these results, it is suggested that the heat-induced aggregation between ovalbumin and lysozyme is due to an electrostatic attraction and sulfhydryl-disulfide interchange between the heatdenatured protein molecules.