Dihydrokaempferol 4-reductase () is an enzyme that catalyzes the chemical reaction

The three substrates of this enzyme are aromadendrin ((+)-dihydrokaempferol), reduced nicotinamide adenine dinucleotide phosphate (NADPH), and a proton. Its products are leucopelargonidin and oxidised NADP+.

This enzyme is an oxidoreductase with the systematic name cis-3,4-leucopelargonidin:NADP+ 4-oxidoreductase. Other names in common use include dihydroflavanol 4-reductase (DFR), dihydromyricetin reductase, NADPH-dihydromyricetin reductase, and dihydroquercetin reductase. It participates in flavonoid biosynthesis.

Function Dihydrokaempferol 4-reductase is part of the biosynthetic pathway to anthocyanidins and anthocyanins, which are common plant pigments.

In addition to converting aromadendrin to leucopelargonidin, it converts ampelopsin ((+)-dihydromyricetin) to leucodelphinidin.

A cDNA for this reductase has been cloned from the orchid Bromheadia finlaysoniana.The isolation, molecular characterization and expression of dihydroflavonol 4-reductase cDNA in the orchid, Bromheadia finlaysoniana. Chye-Fong Liew, Chiang-Shiong Loh, Chong-Jin Goh and Saw-Hoon Lim, Plant Science, Volume 135, Issue 2, 10 July 1998, Pages 161–169,

Researchers in Japan have genetically manipulated roses by using RNA interference to knock out the endogenous enzyme and add a gene for an alternative reductase found in an iris; or add a gene for the blue pigment, delphinidin, to create a blue rose, which is being sold worldwide.Katsumoto Y et al (2007) Engineering of the Rose Flavonoid Biosynthetic Pathway Successfully Generated Blue-Hued Flowers Accumulating Delphinidin Plant Cell Physiol. 48(11): 1589–1600 Phys.Org website. April 4, 2005 Plant gene replacement results in the world's only blue rose

Dihydrokaempferol 4-reductase is also an enzyme on the lignin biosynthesis pathway. In Arabidopsis thaliana, the enzyme uses sinapaldehyde or coniferyl aldehyde or coumaraldehyde to produce sinapyl alcohol or coniferyl alcohol or coumaryl alcohol respectively.

Structural studies As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .

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Further reading