Biosynthesis of proanthocyanidins

Matsui, K., Tanaka, H., and Ohme-Takagi, M., Suppression of the biosynthesis of proanthocyanidin in Arabidopsis by a chimeric PAPl repressor. Plant Biotech. J., 2, 487, 2004. 

Key intermediates in the biosynthesis of proanthocyanidin polymers seem to be flav-3-en-3-ol derivatives or biological equivalents. These intermediates allow plants to synthesize either cis- or trans-stereochemistry with equal facility. 

Kristiansen K N 1984 Biosynthesis of proanthocyanidins in barley Genetic control of the conversion of dihydroquercetin to catechin and procyanidins. Carlsberg Res Commun 49 503-524... 

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