A new class EC 7, Translocases, has been added to the EC list. It will be part of ENZYME from release 2018_10. Read more about EC 7 here.
ENZYME entry: EC 1.23.5.1
| Accepted Name |
|---|
| Violaxanthin de-epoxidase.
|
| Alternative Name(s) |
|---|
| VDE. |
| Reaction catalysed |
|---|
| Violaxanthin + 2 L-ascorbate <=> antheraxanthin + 2 L-dehydroascorbate + H(2)O |
| Comment(s) |
|---|
- Along with EC 1.14.15.21, this enzyme forms part of the xanthophyll
(or violaxanthin) cycle for controlling the concentration of
zeaxanthin in chloroplasts.
- It is activated by a low pH of the thylakoid lumen (produced by high
light intensity).
- Zeaxanthin induces the dissipation of excitation energy in the
chlorophyll of the light-harvesting protein complex of photosystem
II.
- In higher plants the enzyme reacts with all-trans-diepoxides, such as
violaxanthin, and all-trans-monoepoxides, but in the alga Mantoniella
squamata, only the diepoxides are good substrates.
- Formerly EC 1.10.99.3.
|
| Cross-references |
|---|
| BRENDA | 1.23.5.1 |
| EC2PDB | 1.23.5.1 |
| ExplorEnz | 1.23.5.1 |
| PRIAM enzyme-specific profiles | 1.23.5.1 |
| KEGG Ligand Database for Enzyme Nomenclature | 1.23.5.1 |
| IUBMB Enzyme Nomenclature | 1.23.5.1 |
| IntEnz | 1.23.5.1 |
| MEDLINE | Find literature relating to 1.23.5.1 |
| MetaCyc | 1.23.5.1 |
| UniProtKB/Swiss-Prot |
|
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