Enzymatic reduction of (+)-dihydroflavonols to flavan-3,4-cis-diols with flower extracts from Matthiola incana and its role in anthocyanin biosynthesis.
A cell-free extract from flowers of Matthiola incana catalyzes a NADPH-dependent stereospecific reduction of (+)-dihydrokaempferol to 3,4-cis-leucopelargonidin (5,7,4'-trihydroxyflavan-3,4-cis-diol). The pH-optimum of this reaction is around 6. The rate of reaction with NADH was about 50% of that found with NADPH. (+)-Dihydroquercetin and (+)-dihydromyricetin were also reduced by the enzyme preparation to the corresponding flavan-3,4-cis-diols. Correlation between the genotype of M. incana and the presence of dihydroflavonol 4-reductase is strong evidence that this enzyme is involved in anthocyanin biosynthesis.
Biologisches Institut II der Universität, Schänzlestrasse 1, D-7800, Freiburg, Federal Republic of Germany.
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W
Heller
G
G
Forkmann
L
L
Britsch
H
H
Grisebach