| | 1 | Author
| Jan Van Brederode, RiaK. Am, Ps-H Einsbroek | Requires cookie* | | | Title
| Structure and Biosynthesis o f Vitexin 2"-0-Xyloside in Silene alba  | | | | Abstract
| In petals o f Silene alba plants o f Armenian populations, vitexin 2"-0-xyloside was demonstrated to be present. The enzyme, catalyzing the transfer of the xylose moiety of UDP-xylose to vitexin, has its optimal activity at pH 7.8. Mg2+ and Mn2+ stimulated the reaction. The K m values were 2 x 10-5 M for vitexin and 3 x 10-5 M for UDP-xylose. | | | |
Reference
| Z. Naturforsch. 36c, 484 (1981); received February 20 1981 | | | |
Published
| 1981 | | | |
Keywords
| Silene, Caryophyllaceae, Biosynthesis, Vitexin 2"-0-Xyloside, Xylosyltransferase | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0484_n.pdf | | | | Identifier
| ZNC-1981-36c-0484_n | | | | Volume
| 36 | |
| 2 | Author
| Jan Van Brederode, Ria Kamps-Heinsbroek | Requires cookie* | | | Title
| Methylation of 3',4' Di-O H C-Glycosyl- flavones in Silene | | | | Abstract
| In green parts of Silene plants of the genotype g lR two methylated flavonoids were found: isoscoparin and isosco-parin 2"-0-rhamnoside. An enzyme has been demonstrated to catalyze the transfer of the methyl moiety of S-adenosyl methionine to iso-orientin and iso-orientin 2"-0-rhamnosi-de. Maximal activity takes place at pH 8.0 -8 .2 . Of the me tal ions Mn2+, Mg2+, Ca2+, Co2+, Zn2+ and Hg2+, only Co2+ stimulated the reaction at conc. > 2 m M . For the methyla tion o f isoorientin the K m values were 4 x 10-6 M for S-ade-nosyl methionine and 0.32 x 10~3 m for iso-orientin. When isoorientin 2"-0-rhamnoside was used as substrate the K m values were 5 x 10"6 m for S-adenosylmethionine and 7 x 10-6 M for iso-orientin 2"-0-rhamnoside. | | | |
Reference
| Z. Naturforsch. 36c, 486 (1981); received February 20 1981 | | | |
Published
| 1981 | | | |
Keywords
| Silene, Caryophyllaceae, Methylation, Biosynthesis, Iso-scoparin | | | |
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| | | | | TEI-XML for
| default:Reihe_C/36/ZNC-1981-36c-0486_n.pdf | | | | Identifier
| ZNC-1981-36c-0486_n | | | | Volume
| 36 | |
| 3 | Author
| Z. Naturforsch | Requires cookie* | | | Title
| Synthese und Dimerisierungsverhalten des l,l-Bis(trimethylsilyl)-2-(2,5-diisopropylphenyl)silens | | | | Abstract
| Tris(trim ethylsilyl)silylmagnesium bromide, (Me^SiX^SiMgBr, reacts with 2.5-diisopropyl-benzaldehyde to give 2,5-diisopropylphenyl-tris(trimethylsilyl)silylmethanol (1). With sodium | | | |
Reference
| Z. Naturforsch. 51b, 370—3 (1996); eingegangen am 21. August 1995 | | | |
Published
| 1996 | | | |
Keywords
| Silenes, Silene Dimerization, 2, 3-Disilanaphthalenes Tetrahydro, 1, 2-Disilacyclobutanes | | | |
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| default:Reihe_B/51/ZNB-1996-51b-0370.pdf | | | | Identifier
| ZNB-1996-51b-0370 | | | | Volume
| 51 | |
| 4 | Author
| Clemens Krempner1, Rhett Kempeb, Hartmut Oehme3 | Requires cookie* | | | Title
| The Thermal Isomerization of a Tetrahydro-2,3-disilanaphthalene into a 1,2-Disilacyclobutane -The Conversion of a Formal Silene [2+4] Cyclodimer into the [2+2] Cycloadduct | | | | Abstract
| 1,2,3,8a-Tetrahydro-1 -mesityl-5,7,8a-trimethyl-2,2,3,3-tetrakis(trimethylsilyl)-2,3-disila-naphthalene (3), the formal [2+4] cyclodimer of the transient 2-mesityl-l,l-bis(trimethylsilyl)-silene (2), on thermal treatment gradually isomerizes to give a mixture of the [2+2] products (E)-and -predominantly -(Z)-3,4-dimesityl-1,1,2,2-tetrakis(trimethylsilyl)-l,2-disilacyclo-butane [(E/Z)-4], By prolonged heating or at higher temperatures both (E/Z)-3 and (Z)-4 are converted into (E)-4, the thermodynamically most stable head-to-head dimer of 2. Possible pathways of the isomerization processes are discussed. | | | |
Reference
| Z. Naturforsch. 52b, 815—818 (1997); received February 14 1997 | | | |
Published
| 1997 | | | |
Keywords
| Silenes, Silene Dimerization, 2, 3-Disilanaphthalene Tetrahydro, 1, 2-Disilacyclobutane | | | |
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| default:Reihe_B/52/ZNB-1997-52b-0815.pdf | | | | Identifier
| ZNB-1997-52b-0815 | | | | Volume
| 52 | |
| 5 | Author
| J. M. Steyns, O. M. Astenbroek, *. @bullet, G. Van Nigtevecht, J. Van Brederode | Requires cookie* | | | Title
| 07g and D6a: Two Flavone Glycosylating Genes in Silene, which are Only Expressed in Cotyledons and Rosette Leaves | | | | Abstract
| Two further loci can be added to the three already known (g , g l and f g) in Silene controlling the 7 -0 and 2"-0-glycosylation o f the C -glycosylflavone isovitexin (6-C -glucosylapigenin). These loci, 0 7 g for the 7-O-galactosylation and D6a for the 2"-0-arabinosylation, appear only to be expressed in cotyledons and rosette leaves and control the biosynthesis o f isovitexin 7 -0 -galactoside and isovitexin 7-0-galactose 2"-0-arabinosid e in these parts o f plants in which the recessive alleles o f the loci g, g l and f g are hom ozygous (Steyns et al. [9]). The possibility that locus g, whose dominant alleles gG and g X control the 7-0-glu cosylation and the 7-0-xylosylation o f isovitexin respectively, controls the synthesis o f isovitexin-7-O -galactoside was excluded by demonstrating the presence o f isovitexin-7-O -galactoside and the 7-0-galactosyltransferase catalyzing its biosynthesis in addition to isovitexin-7-O -glucoside and the 7-0-glucosyltransferase in cotyledons o f gGgG seedlings. The synthesis o f the 2"-0-arabinoside is neither controlled by locus gl, whose dom inant alleles glR and glA control the 2"-0-rham nosylation and 2"-0-arabinosylation o f isovitexin respectively, nor by locus fg, whose dom inant allele Fg controls the biosynthesis o f isovitexin 2"-0-glucoside. This was shown by the presence o f isovitexin-7-O -galactose 2"-0-arabinosid e and the 2"-0-arabinosyltransferase catalyzing the synthesis o f the 2"-0-arabinosid e in addition to isovitexin-7-O-galactose 2"-0-rham noside in cotyledons o f g lR g lR seedlings and by the presence o f isovitexin-7-O-galactose 2"-0-arabinoside and the 2"-0-arabinosyltransferase in addition to isovitexin-7-O-galactose 2"-0-glucoside and the 2"-0-glucosyltransferase in cotyledons o f FgFg seedlings. | | | |
Reference
| Z. Naturforsch. 39c, 568—5 (1984); received January 26/M arch 16 1984 | | | |
Published
| 1984 | | | |
Keywords
| Silene, Flavone Glycosylation Genes, O 7g: Isovitexin 7-O -G alactoside, D6a: Isovitexin 2"-0-A rabinoside, Ontogeny | | | |
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| default:Reihe_C/39/ZNC-1984-39c-0568.pdf | | | | Identifier
| ZNC-1984-39c-0568 | | | | Volume
| 39 | |
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