CD spectra and redox reactions of superoxide dismutase from Escherichia coli B: evidence for a Mn(III) enzyme.

Analysis of the metal content, CD and EPR spectra, and reaction with H(2)O(2) and ferrocyanide have been carried out on E. coli superoxide dismutase, which contains manganese as the metal prosthetic group. The results obtained indicate that the metal is present in the enzyme as a high spin Mn(III) complex of highly distorted octahedral symmetry, in the ratio of approximately 1 atom of manganese per enzyme dimer.