Proton magnetic resonance studies of human lysozyme

The high pK value of the single histidine residue of human lysozyme (7.1 at 32°C), together with thermodynamic data, indicate that this histidine is in a negatively charged environment and is partially buried. The histidine residue is not at the binding site for oligosaccharide inhibitors. Highly shielded tryptophan residues are at the binding site and are involved identically in the binding of both di and tri-N-acetylglucosamine.