Identity of amino acid sequences of superoxide dismutase purified from both anaerobically maintained and aerated Porphyromonas gingivalis.

Superoxide dismutase (SOD) from anaerobically maintained Porphyromonas gingivalis (anaero-SOD) has the characteristic of Fe-SOD, whereas SOD from aerated cells (aero-SOD) has that of Mn-SOD. However, both types of apoSOD can bind either Fe or Mn. To elucidate the structure relationship between anaero- and aero-SOD, we examined the amino acid sequence of aero-SOD by direct protein analysis. The amino acid sequence of aero-SOD was shown to be identical with that of anaero-SOD determined previously. Our findings support the hypothesis that cambialistic SOD is formed from a single apoprotein in bacterial cells.