- Mutation of the metal-bridging proton-donor His63 residue in human Cu, Zn superoxide dismutase. Biochemical and biophysical analysis of the His63-->Cys mutant. Banci, L., Bertini, I., Borsari, M., Viezzoli, M.S., Hallewell, R.A. Eur. J. Biochem. (1995)