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'Flavonols' in keywords Facet   Publication Year 1992  [X]
Facet   section ZfN Section C:Volume 047  [X]
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1Author    K. Stich, T. Eidenberger, F. W. Urst, G. ForkmRequires cookie*
 Title    Flavonol Synthase Activity and the Regulation of Flavonol and Anthocyanin Biosynthesis during Flower Development in Dianthus caryophyllus L. (Carnation)  
 Abstract    Flavonol synthase (FLS) was demonstrated in crude extracts from flower buds o f Dianthus caryophyllus (carnation). The enzyme catalyzed the conversion o f dihydrokaempferol and dihydroquercetin to kaempferol and quercetin, respectively. The reaction required 2-oxoglutarate, ferrous ion and ascorbate as co-factors and had a pH optimum at about 7.4. The demonstration o f FLS activity allowed comparative studies on flavonol and anthocyanin biosynthesis during bud and flower developm ent. Besides FLS the flavonoid enzymes chal­ cone synthase (CHS), flavanone 3-hydroxylase (FH T) and dihydroflavonol 4-reductase (D F R) were measured. D F R is specifically involved in anthocyanin synthesis, while CHS and FHT provide dihydroflavonol, the com m on substrate for both FLS and D F R . Maximum ex­ pression o f CHS, FHT and FLS activity was already observed in small buds, whereas D FR activity started to increase much later and reached its highest level in opened flowers. A sub­ stantial correlation was observed between the time courses o f FLS and D F R activity and the accumulation o f flavonols and anthocyanins, respectively. The com petition o f FLS and D F R for dihydroflavonols was found to be largely circumvented by different substrate specificities and by the sequential expression o f the two enzymes. Both flavonols and anthocyanins are obviously not, or only to some extent, subject to degradation. 
  Reference    Z. Naturforsch. 47c, 553 (1992); received February 17/April 21 1992 
  Published    1992 
  Keywords    Anthocyanins, Flavonoid Enzymes, Flavonols, Flower D evelopm ent, Dianthus caryophyllus 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0553.pdf 
 Identifier    ZNC-1992-47c-0553 
 Volume    47