Title: Flavan-3,4-diols in anthocyanin biosynthesis, enzymatic formation with flower extracts from Callistephus chinensis
Abstract: Feeding of leucopelargonidin and leucocyanidin, but not of naringenin or dihydroquercetin, to petals of an acyanic mutant of Callistephus chinensis, blocked by recessive alleles of the gene F, led to formation of the respective anthocyanidin glucosides, whereas in a further acyanic mutant, blocked by recessive alleles of the gene A, none of these compounds initiated anthocyanin synthesis. The results strongly support the role of flavan-3,4-diols in anthocyanin biosynthesis. Moreover, in enzyme preparations from cyanic Callistephus flowers, dihydroflavonol 4-reductase activity was demonstrated catalysing the stereospecific reduction of (+)-dihydrokaempferol to (+)-3,4-cis-leucopelargonidin with NADPH as co-factor. With NADH the reaction rate was only about 35% of that observed with NADPH. A pH-optimum around 6.7 was determined. In agreement with the anthocyanidin pattern of Callistephus flowers, (+)-dihydroquercetin and (+)-dihydromyricetin were also reduced by the enzyme preparations to the respective flavan-3,4-cis-diols. They are even better substrates than dihydrokaempferol. As expected from the feeding experiments, the gene F but not the gene A controls dihydroflavonol 4-reductase activity; enzyme activity is in addition controlled by gene G.
Publication Year: 1988
Publication Date: 1988-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 26
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