Copper-zinc superoxide dismutase from the marine yeast Debaryomyces hansenii

We have isolated the cytosolic form of Cu-Zn superoxide dismutase (SOD) from the marine yeast Debaryomyces hansenii. This enzyme has a subunit mass of 18 kDa. The preparation was found to be heterogeneous by IF electrophoresis with two pI ranges: 5.14-4.0 and 1.6-1.8. The enzyme preparation had a remarkably strong stability at pH 6.0-7.0, surviving boiling for 10 min without losing more than 60% of activity. On Western blots, this enzyme was recognized by antibodies raised in rabbits against D. hansenii extracts, while only a weak cross-reaction could be detected using antibodies generated against either Saccharomyces cerevisiae or bovine erythrocyte Cu-Zn SODs. In sequencing analysis, a peptide obtained by trypsin digestion was found to have 85% identity to the S. cerevisiae Cu-Zn SOD.