Table 3. Enzymes involved in the oxidative stress response.
| Protein | #Spiro | #Giardia | Function |
| FAD/FMN dependent oxidoreductase | 3 | 1 | O2 to O2− |
| NADH oxidase | 4 | 1 | O2 to O2− |
| NADPH oxidoreductase | 3 | 1 | O2 to O2− |
| Nitroreductase | 3 | 1 | O2 to O2− |
| A-type flavoprotein | 7 | 1 | O2 to H2O |
| Superoxide reductase | 1 | 1 | O2− to H2O2 |
| Hybrid cluster protein | 2 | 1 | H2O2 to H2O |
| Peroxiredoxin | 4 | 3 | H2O2 to H2O |
| Protein containing alkyl hydroperoxide reductase | 1 | 3 | H2O2 to H2O |
| Rubrerythrin 1 | 5 | 0 | H2O2 to H2O |
| Peptide methionine sulfoxide reductase MsrA | 2 | 1 | repair of oxidative damaged proteins |
| Peptide methionine sulfoxide reductase MsrB | 2 | 1 | repair of oxidative damaged proteins |