The detection of mercury, lead, and methylmercury binding sites on lysozyme by carbon-13 NMR chemical shifts of the carboxylate groups.

The chemical shift changes observed in the carbon-13 NMR spectra of the carboxylate region in conjunction with previous fluorescence data indicate that mercury and lead bind to both disulfide bridge 64-80 and to Asp-52 in hen egg-white lysozyme. Methylmercury appears to bind primarily to the disulfide linkage. The carbon-13 NMR results support previous investigations by halide ion NMR and x-ray crystallography. The combined information from all of these techniques is useful for providing a clearer description of heavy metal binding to proteins.