Nature of the binding site around and reactivity of histidine-15 in lysozyme

Bromoacetamide derivatives having n-alkyl substituents (BrCH2CONH(CH2)nH, 1-n) and carboxyalkyl substituents (BrCH2CONH(CH2)nCOOH, 2-n) react with His-15 in lysozyme exclusively at N epsilon 2 at pH 5.5 and 40 degree C. Kinetic studies suggest that lysozyme has a small hydrophobic pocket that binds these reagents in the vicinity of His-15.