Pathway · 2 proteins
Peroxide and superoxide handling
Detoxification enzymes limit selected reactive-oxygen species.
How it works
- Superoxide dismutases and several peroxidase families address different reactive-oxygen species. YaaA is a peroxide-stress-associated protein, not an additional peroxidase assigned here.
- Superoxide dismutase converts superoxide into oxygen and hydrogen peroxide. Peroxidases then reduce suitable peroxides using electron donors; the cytochrome-c and thioredoxin-linked systems use different partners.
- Defense therefore requires both removal reactions and regeneration of their electron donors. Enzyme annotations do not determine actual stress exposure, quantitative capacity or which route dominates in VF5.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Superoxide dismutase [Fe] | 1.15.1.1 | 2 superoxide + 2 H(+) = H2O2 + O2 | Fe cation | 213 | Step named |
| Uncharacterized protein | — | — | — | 227 | Unspecified |
Origins
How could a cell survive reactive oxygen before it had enzymes to destroy it?
None of the books searched discusses the origin of oxygen-detoxifying enzymes.
Superoxide dismutase has charged patches on its surface that steer superoxide toward the metal at its centre. The hydrogen peroxide it produces must then be removed by a second enzyme, so protection needs both working in sequence.
From the books: Horton et al., Principles of Biochemistry, p. 217.
The wider question for this part of the cell: origins for surviving oxygen damage.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: Damaged-protein turnover · Not yet placed in a pathway