Chlorophyll(ide) b reductase

Chlorophyll(ide) b reductase (EC 1.1.1.294, chlorophyll b reductase, Chl b reductase) is an enzyme with systematic name 71-hydroxychlorophyllide-a:NAD(P)⁺ oxidoreductase.^[1]^[2]^[3]^[4]^[5] This enzyme catalyses the following chemical reaction

71-hydroxychlorophyllide a + NAD(P)⁺

\rightleftharpoons

chlorophyllide b + NAD(P)H + H⁺

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, and it also forms part of the chlorophyll cycle, which interconverts chlorophyll a and b in response to changing light conditions.

References

↑ Scheumann, V.; Ito, H.; Tanaka, A.; Schoch, S.; Rüdiger, W. (1996). "Substrate specificity of chlorophyll(ide) b reductase in etioplasts of barley (Hordeum vulgare L.)". Eur. J. Biochem. 242 (1): 163–170. doi:10.1111/j.1432-1033.1996.0163r.x. PMID 8954166.
↑ Scheumann, V.; Schoch, S.; Rüdiger, W. (1998). "Chlorophyll a formation in the chlorophyll b reductase reaction requires reduced ferredoxin". J. Biol. Chem. 273 (52): 35102–35108. doi:10.1074/jbc.273.52.35102. PMID 9857045.
↑ Hörtensteiner, S. (2006). "Chlorophyll degradation during senescence". Annu. Rev. Plant Biol. 57: 55–77. doi:10.1146/annurev.arplant.57.032905.105212. PMID 16669755.
↑ Ito, H.; Ohtsuka, T.; Tanaka, A. (1996). "Conversion of chlorophyll b to chlorophyll a via 7-hydroxymethyl chlorophyll". J. Biol. Chem. 271 (3): 1475–1479. doi:10.1074/jbc.271.3.1475. PMID 8576141.
↑ Rüdiger, W. (2002). "Biosynthesis of chlorophyll b and the chlorophyll cycle". Photosynth. Res. 74: 187–193. doi:10.1023/A:1020959610952. PMID 16228557.

External links

Chlorophyll(ide) b reductase at the US National Library of Medicine Medical Subject Headings (MeSH)

Oxidoreductases: alcohol oxidoreductases (EC 1.1)

1.1.1: NAD/NADP acceptor	3-hydroxyacyl-CoA dehydrogenase 3-hydroxybutyryl-CoA dehydrogenase Alcohol dehydrogenase Aldo-keto reductase 1A1 1B1 1B10 1C1 1C3 1C4 7A2 Aldose reductase Beta-Ketoacyl ACP reductase Carbohydrate dehydrogenases Carnitine dehydrogenase D-malate dehydrogenase (decarboxylating) DXP reductoisomerase Glucose-6-phosphate dehydrogenase Glycerol-3-phosphate dehydrogenase HMG-CoA reductase IMP dehydrogenase Isocitrate dehydrogenase Lactate dehydrogenase L-threonine dehydrogenase L-xylulose reductase Malate dehydrogenase Malate dehydrogenase (decarboxylating) Malate dehydrogenase (NADP+) Malate dehydrogenase (oxaloacetate-decarboxylating) Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) Phosphogluconate dehydrogenase Sorbitol dehydrogenase Hydroxysteroid dehydrogenase: 3 Beta 3-beta-HSD NSDHL 11 Beta HSD11B1 HSD11B2 17 Beta

1.1.2: cytochrome acceptor	D-lactate dehydrogenase (cytochrome) D-lactate dehydrogenase (cytochrome c-553) Mannitol dehydrogenase (cytochrome)

1.1.3: oxygen acceptor	Glucose oxidase L-gulonolactone oxidase Xanthine oxidase

1.1.4: disulfide as acceptor	Vitamin K epoxide reductase Vitamin-K-epoxide reductase (warfarin-insensitive)

1.1.5: quinone/similar acceptor	Malate dehydrogenase (quinone) Quinoprotein glucose dehydrogenase

1.1.99: other acceptors	Choline dehydrogenase L2HGDH

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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