Arginine ethylester prevents thermal inactivation and aggregation of lysozyme

Arginine is a versatile additive to prevent protein aggregation. This paper shows that arginine ethylester (ArgEE) prevents heat-induced inactivation and aggregation of hen egg lysozyme more effectively than arginine or guanidine. The addition of ArgEE decreased the melting temperature of lysozyme. This data could be interpreted in terms of ArgEE binding to unfolded lysozyme, possibly through the ethylated carboxyl group, which leads to effective prevention of intermolecular interaction among aggregation-prone molecules. The data suggest that ArgEE could be used as an additive to prevent inactivation and aggregation of heat-labile proteins.