Nature of the Binding Site Around and Reactivity of Histidine-15 in Lysozyme

Abstract
Bromoacetamide derivatives having n -alkyl substituents (BrCH 2 CONH(CH 2 ) n H, 1- n ) and carboxyalkyl substituents (BrCH 2 CONH(CH 2 ) n COOH, 2- n ) react with His-15 in lysozyme exclusively at N 2 at pH 5.5 and 40°C. Kinetic studies suggest that lysozyme has a small hydrophobic pocket that binds these reagents in the vicinity of His-15.