Abstract:After treating the MoFe protein from Azotobacter vinelandii with H2O2, the Mo and Fe contents, C2H2-reduction activity, molecular extinction coefficient and α-helix of the treated protein were significantly decreased; and the polypeptides of the protein might be partially degraded. The damage of MoFe protein by H2O2 could be avoided by addition of peroxidase purified from A. vinelandii before the addition of H2O2. The results showed that the metal clusters and protein structure of MoFe protein could be remarkably damaged by H2O2 and peroxidase could protect nitrogenase against the damage by H2O2.