IUBMB Enzyme Nomenclature


Accepted name: chlorophyll(ide) b reductase

Reaction: 71-hydroxychlorophyllide a + NAD(P)+ = chlorophyllide b + NAD(P)H + H+

For diagram of reaction click here.

Other name(s): chlorophyll b reductase; Chl b reductase

Systematic name: 71-hydroxychlorophyllide-a:NAD(P)+ oxidoreductase

Comments: This enzyme carries out the first step in the conversion of chlorophyll b to chlorophyll a. It is involved in chlorophyll degradation, which occurs during leaf senescence [3] and it also forms part of the chlorophyll cycle, which interconverts chlorophyll a and b in response to changing light conditions [4,5].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Scheumann, V., Ito, H., Tanaka, A., Schoch, S. and Rüdiger, W. Substrate specificity of chlorophyll(ide) b reductase in etioplasts of barley (Hordeum vulgare L.). Eur. J. Biochem. 242 (1996) 163-170. [PMID: 8954166]

2. Scheumann, V., Schoch, S. and Rüdiger, W. Chlorophyll a formation in the chlorophyll b reductase reaction requires reduced ferredoxin. J. Biol. Chem. 273 (1998) 35102-35108. [PMID: 9857045]

3. Hörtensteiner, S. Chlorophyll degradation during senescence. Annu. Rev. Plant Biol. 57 (2006) 55-77. [PMID: 16669755]

4. Ito, H., Ohtsuka, T. and Tanaka, A. Conversion of chlorophyll b to chlorophyll a via 7-hydroxymethyl chlorophyll. J. Biol. Chem. 271 (1996) 1475-1479. [PMID: 8576141]

5. Rüdiger, W. Biosynthesis of chlorophyll b and the chlorophyll cycle. Photosynth. Res. 74 (2002) 187-193. [PMID: 16228557]

[EC created 2007]

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