ZfN: Search Results

1	Author	R. R. Br, G. Spribille, Forkm	Requires cookie*
	Title	Genetic Control of Chalcone Synthase Activity in Flowers of Matthiola incana
	Abstract	Chalcone synthase activity was demonstrated in enzyme preparations from flowers o f defined genotypes of Matthiola incana (stock). The product formed from 4-coumaroyl-CoA and malonyl-CoA was naringenin and not the isomeric chalcone, because chalcone isomerase was also present in the reaction mixture. Chalcone synthase activity could be detected only in flower extracts o f genotypes with wild-type alleles at the locus f Thus, the interruption of the anthocyanin pathway in white flowering lines with recessive alleles (ff) of this gene is clearly due to a lack o f this enzyme activity. Independent on the genetic state of the locus b which controls the formation of pelargonidin or cyanidin, respectively, in the flowers, 4-coumaroyl-CoA was the only suitable substrate for the condensation reaction.
	Reference	Z. Naturforsch. 36c, 619 (1981); received April 3 1981
	Published	1981
	Keywords	Anthocyanins, Flavonoids, Chalcone Synthase, Genetic Control, Matthiola incana
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	TEI-XML for	default:Reihe_C/36/ZNC-1981-36c-0619.pdf
	Identifier	ZNC-1981-36c-0619
	Volume	36

2	Author	G. Forkm, P. De Vlaming, R. Spribille, H. Wiering, A. W. Schram	Requires 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

3	Author	John Kamsteega, Jan Van Brederode, Gerrit Van Nigtevecht	Requires cookie*
	Title	Campion (Silene dioica)
	Abstract	An enzyme catalyzing the transfer of the rhamnosyl moiety of UDP-L-rhamnose to the 6 -hydro-xyl group of the 3-O-bound glucose of anthocyanidin 3-O-glucosides has been demonstrated in petal extracts of Silene dioica plants. The enzyme activity is controlled by a single dominant gene N\ no rhamnosyltransferase activity is found in petals of n/n plants. The 60-fold purified rhamno-syltransferase exhibits a pH optimum of 8.1, has a molecular weight of about 45000 daltons, is sti mulated by the divalent metal ions Mg2+, Mn2+ and Co2+, and has a "true Km" value of 0.09 mM for UDP-L-rhamnose and 2.2 mM for cyanidin 3-O-glucoside. Pelargonidin 3-O-glucoside and delphinidin 3-O-glucoside can also serve as acceptor. The enzyme can also catalyze the rhamnosy-lation of anthocyanidin 3,5-diglucosides although at reduced rate. The biosynthetic pathway for the synthesis of cyanidin 3-rhamnosylglucoside-5-glucoside in petals of S. dioica is discussed.
	Reference	Z. Naturforsch. 35c, 249—257 (1980); received October 22 1979
	Published	1980
	Keywords	Silene dioica, Caryophyllaceae, Anthocyanin Biosynthesis, Cyanidin-, Pelargonidin-glycosides, Glycosyltransferases, Genetic Control
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	TEI-XML for	default:Reihe_C/35/ZNC-1980-35c-0249.pdf
	Identifier	ZNC-1980-35c-0249
	Volume	35

4	Author	G. Forkmann, G. Stotz	Requires cookie*
	Title	Genetic Control of Flavanone 3-Hydroxylase Activity and Flavonoid 3'-Hydroxylase Activity in Antirrhinum majus (Snapdragon)
	Abstract	In flower extracts o f defined genotypes o f Antirrhinum majus, two different hydroxylases were found catalysing the hydroxylation o f naringenin and eriodictyol in the 3-position and of naringenin in the 3'-position. The 3-hydroxylase is a soluble enzyme and belongs according to its cofactor requirement to the 2-oxoglutarate-dependent dioxygenases. Investigations on different genotypes revealed a clear correlation between block o f the anthocyanin pathway by recessive alleles of the gene inc and a complete lack of 3-hydroxylase activity. Chemogenetic studies on different genotypes suggested that the 3'-hydroxyl group of the B-ring of flavonoids is introduced at the stage of C15 intermediates. The corresponding 3'-hydroxylase was found to be localized in the microsomal fraction and required NADPH as cofactor. In confirmation o f the chemogenetic studies, a strict correlation was found between 3'-hydroxylase activity and the gene eos which is known to control the hydroxylation o f flavones, flavonols and anthocyanins in the 3'-position. These results are similar to those previously obtained with Matthioia incana.
	Reference	Z. Naturforsch. 36c, 411 (1981); received January 20 1981
	Published	1981
	Keywords	Anthocyanin Biosynthesis, Antirrhinum majus, Flavonoids, Flavanone 3-Hydroxylase, Flavonoid 3'-Hydroxylase, Genetic Control
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	TEI-XML for	default:Reihe_C/36/ZNC-1981-36c-0411.pdf
	Identifier	ZNC-1981-36c-0411
	Volume	36