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'Flavonols' in keywords Facet   section ZfN Section C  [X]
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1Author    JosieL. Shute, PabloS. Jourdan, RichardL. MansellRequires cookie*
 Title    UDP-Glucose: Glucosyltransferase Activity Involved in the Biosynthesis of Flavonol Triglucosides in Pisum sativum L. Seedlings  
 Abstract    From young, light-grown seedlings o f Pisum sativum L. an enzyme activity catalyzing the glu-cosylation o f kaempferol and quercetin in the 3-position to form the 3-0-triglucoside derivative has been demonstrated. The reaction proceeds from the aglycone via the mono-and diglucoside intermediates. The triglucoside can be produced from any o f the less substituted derivatives with uridine diphosphate-Z)-glucose (U D P G) as the glucosyl donor. Young leaf tissues had much high­ er levels o f glucosyltransferase activity than the petioles and internodes. This is the first report o f the synthesis o f flavonol-3-0-triglucosides in vitro. 
  Reference    Z. Naturforsch. 34c, 738 (1979); received June 25 1979 
  Published    1979 
  Keywords    Pisum sativum, Peas, Flavonols, Triglucosides, Glucosyltransferase 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0738.pdf 
 Identifier    ZNC-1979-34c-0738 
 Volume    34 
2Author    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 
3Author    Nariyuki Ishikura, Zhi-Qing YangRequires cookie*
 Title    UDP-D-Xylose: Flavonol 3-O-Xylosyltransferase from Young Leaves of Euonymus alatus f. ciliato-dentatus  
 Abstract    From the young leaves of Euonymus alatus f. ciliato-dentatus, a novel enzyme, UDP-D-xylose: flavonol 3-O-xylosyltransferase (F 3 X T), catalyzing the transfer o f D-xylose from UDP-D-xylose to the 3 position o f 3,5,7,4'-tetrahydroxyflavone (kaempferol), was detected and purified about 16-fold by precipitation with am m onium sulfate and DEAE-cellulose CC, by which F 3 X T was separated from two coexisting flavonol O-glucosyltransferases (FGT). Thus, F 3 XT was isolated as a soluble enzyme with a pH optim um o f 7.0 in Tris-HCl buffer. The molecular weight o f F 3 X T , which had an isoelectric point at pH 6.1, was estimated by elution from a column o f Sephadex G-100 to be about 48 kDa. The activity o f F 3 X T was stimulated by 14 mM 2-ME and strongly inhibited by 1 mM C u 2+, 1 mM Z n 2+, and various re­ agents that react with sulfhydryl groups. Am ong the substrates tested for F 3 X T , kaempferol was the best. The Km values for kaempferol and UDP-xylose were determined to be 0.83 jim and 25 |iM, respectively. F 3 X T mediated the transfer o f xylose exclusively to the 3-hydroxyl group o f kaempferol. Isorhamnetin, quercetin and fisetin also can function as xylosyl acceptor though less efficiently, but neither the 7-O-glucosides nor the 3-O-glucosides o f kaempferol and quercetin were able to accept D-xylose. Dihydroflavonols were not xylosylated. 
  Reference    Z. Naturforsch. 46c, 1003—1010 (1991); received February 28/June 28 1991 
  Published    1991 
  Keywords    Celastraceae, Euonymus, Flavonol, O-Xylosyltransferase, Characterization 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-1003.pdf 
 Identifier    ZNC-1991-46c-1003 
 Volume    46 
4Author    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 
5Author    G. Forkm, P. De Vlaming, R. Spribille, H. Wiering, A. W. SchramRequires cookie*
 Title    Genetic and Biochemical Studies on the Conversion of Dihydroflavonols to Flavonols in Flowers of Petunia hybrida  
 Abstract    Soluble enzyme preparations from flower buds of Petunia hybrida catalyzed the conversion of dihydroflavonols to flavonols. Dihydrokaempferol and dihydroquercetin were readily converted to the respective flavonols, whereas dihydromyricetin was a poor substrate. The reaction required 2-oxoglutarate, ascorbate and Fe2+ as cofactors and had a pH optimum at about 6.5. In the presence of the dominant allele FI, high enzyme activity for flavonol formation was found, whereas in enzyme preparations from flower buds of recessive genotypes (fl/fl) only low enzyme activity could be observed. A substantial correlation was found between enzyme activity for flavonol formation and the flavonol content of buds and flowers during development. 
  Reference    Z. Naturforsch. 41c, 179 (1986); received July 27/September 26 1985 
  Published    1986 
  Keywords    birthday Dioxygenase, Flavonoid Biosynthesis, Flavonols, Genetic Control, Petunia hybrida 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0179.pdf 
 Identifier    ZNC-1986-41c-0179 
 Volume    41 
6Author    Dieter Strack, Jürgen Heilemann, Eva-Susan Klinkott, Victor WrayRequires cookie*
 Title    Cell Wall-Bound Phenolics from Norway Spruce (Picea abies) Needles  
 Abstract    Insoluble phenolics have been isolated and identified from Norway spruce (Picea abies [L.] KARST.) needles as cell wall-bound astragalin (kaempferol 3-O-ß-glucoside) and p-coumaric acid as major components, and ferulic acid as a minor one. They probably mainly occur as lignin-carbohydrate complexes. 
  Reference    Z. Naturforsch. 43c, 37—41 (1988); received August 25 1987 
  Published    1988 
  Keywords    Picea abies (L) KARST, Hydroxycinnamic Acids, Flavonols, Cell Wall, Localization 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0037.pdf 
 Identifier    ZNC-1988-43c-0037 
 Volume    43 
7Author    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 
8Author    Maurice Jay, Vincenzo De Luca, Ragai IbrahimRequires cookie*
 Title    Meta-Methylation o f Flavonol Rings A (8-) and B (3'-) Is Catalysed by Two Distinct O-Methyltransferases in Lotus corniculatus  
 Abstract    Two O-methyltransferases specific for flavonol rings A and B were isolated from young flower buds of Lotus corniculatus. They were partially purified by ammonium sulphate precipitation and successive chromatography on Sephadex G-100 and Polybuffer ion exchanger. One enzyme focused at pi 5.5 and catalysed the O-methylation of position 8 of flavonols with a pH optimum of 8.1. The other enzyme had a pi o f 5.1 and preferentially attacked position 3' at an optimum pH of 7.7. The methylated products o f both enzymes seem to contribute to the flower colour of Lotus and may be used as biochemical markers in genetic studies of this genus. 
  Reference    Z. Naturforsch. 38c, 413 (1983); received December 21 1982 
  Published    1983 
  Keywords    Lotus corniculatus, Leguminosae, O-Methyltransferase, Flavonols, 8-O-Methylation, 3'-0-Methylation 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0413.pdf 
 Identifier    ZNC-1983-38c-0413 
 Volume    38