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'Flavonols' in keywords Facet   section ZfN Section C:Volume 039  [X]
Facet   Publication Year 1984  [X]
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1Author    R. R. Br, G. Spribille, ForkmannRequires cookie*
 Title    Conversion of Dihydroflavonols to Flavonols with Enzyme Extracts from Flower Buds of Matthiola incana  
 Abstract    Soluble enzyme preparations from flower buds of Matthiola incana catalysed the conversion of dihydrokaempferol to kaempferol and of dihydroquercetin to quercetin. The reaction required 2-oxoglutarate, ascorbate and Fe2+ as cofactors and had a pH-optimum at about 7.0. Highest enzyme activity was already present in the youngest buds followed by a rapid decline during bud and flower development. Furthermore, a substantial correlation was observed between the enzyme activity for flavonol formation and the flavonol content of the buds and flowers. 
  Reference    Z. Naturforsch. 39c, 714—719 (1984); received April 4/May 23 1984 
  Published    1984 
  Keywords    Dioxygenase, Flavonoid Biosynthesis, Flavonols, Matthiola incana 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0714.pdf 
 Identifier    ZNC-1984-39c-0714 
 Volume    39 
2Author    L.M V Jonsson, M.E G Aarsman, J. Bastiaannet, W.E D Onker-K, A.G M Oopm An, A. W. Geräts, SchramRequires cookie*
 Title    Common Identity of UDP-Glucose: Anthocyanidin 3-O-Glucosyltransferase and UDP-Glucose: Flavonol 3-O-Glucosyltransferase in Flowers of Petunia hybrida  
 Abstract    In an attempt to distinguish between the U D P -glucose: flavonol 3-O -glucosyltransferase (3G T) and the UD P-glucose:anthocyanidin 3-O-glucosyltransferase in flower buds o f Petunia hybrida, several properties o f these activities were determ ined. The 3-glucosylation o f anthocyanidin had a pH-activity optimum o f 7.2, that o f flavonol pH 9.2 to 9.5. A nthocyanidin 3 G T activity was lowered in the presence o f EDTA or /?-mercaptoethanol, but this was due to an effect on the anthocyanidin substrate. The two 3-glucosylating activities were to a sim ilar extent inhibited by an increasing ionic strength in the enzyme assay and showed an identical iso-electric point (5.2) as determined by chromatofocusing. M olecular weights were identical: 26000, 52000 or 78000 daltons as determined by gel-filtration. Antiserum raised against partially purified 3 G T gave identical immunoprecipitation curves with flavonol 3 G T and anthocyanidin 3G T . Special attention was given to the 3-O-glucosyltransferase in mutants with low levels o f 3 G T activity. These mutants are unable to form significant am ounts o f anthocyanins but contain wild-type amounts o f flavonols. The enzyme o f such mutants had the sam e iso-electric point and identical titration-curves with antiserum as the enzym e from w ildtype plants. 3 G T from w ildtype or mutant plants glucosylated flavonols at higher rates than anthocyanidins. 
  Reference    Z. Naturforsch. 39c, 559 (1984); received February 21 1984 
  Published    1984 
  Keywords    Petunia hybrida, Anthocyanins Flavonoid Biosynthesis, Flavonols, 3-O -G lucosyltransferase 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0559.pdf 
 Identifier    ZNC-1984-39c-0559 
 Volume    39