ENZYME

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 1.1.1.294

Accepted Name

Chlorophyll(ide) b reductase.

Alternative Name(s)

Chl b reductase.

Chlorophyll b reductase.

Reaction catalysed

7(1)-hydroxychlorophyllide a + NAD(P)(+) <=> chlorophyllide b + NAD(P)H

Comment(s)

Carries out the first step in the conversion of chlorophyll b to chlorophyll a.
Involved in chlorophyll degradation, which occurs during leaf senescence and it also forms part of the chlorophyll cycle, which interconverts chlorophyll a and b in response to changing light conditions.
While both chlorophyll a and chlorophyll b are found in higher plants, only breakdown products derived from chlorophyll a are found in the end products, i.e. non-fluorescent chlorophyll catabolites (NCCs).
The transition from chlorophyll b, which contains a formyl group on C7, to chlorophyll a, which contains a methyl group on C7, proceeds through the intermediate 7(1)-hydroxychlorophyll.
Another enzyme, which requires ferredoxin but has not been characterized fully, is required to complete the conversion.

Cross-references

PROSITE

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature