| | 2 | Author
| StewartA. Brown | Requires cookie* | | | Title
| Biosynthesis of Daphnetin in Daphne mezereum L.  | | | | Abstract
| Shoots of Daphne mezereum synthesized daphnetin (7,8-dihydroxycoumarin) more efficiently from [2-l4C]umbelliferone (7-hydroxycoumarin) than from [2-l4C]p-coumaric acid, and [2-14C]caf-feic acid was more poorly utilized still. These findings do not support the idea of derivation of daphnetin via hydroxylation of the caffeic acid ring at the 2 position, followed by lactone ring formation; instead they are consistent with the concept of daphnetin formation by an additional hydroxylation of umbelliferone at C-8. Umbelliferone was recovered with little l4C dilution from emulsin-hydrolysed extracts of shoots fed labelled umbelliferone, and TLC of extracts from un treated shoots revealed two substances yielding umbelliferone on hydrolysis. Evidence is pre sented from TLC and HPLC analysis that one of these is skimmin (7-O-ß-D-glucosylumbel-liferone), not previously reported from Daphne. The tracer experiments further support the theory that umbelliferone is the general precursor of coumarins bearing two or more hydroxyl functions on the aromatic ring. | | | |
Reference
| Z. Naturforsch. 41c, 247 (1986); received November 4 1985 | | | |
Published
| 1986 | | | |
Keywords
| Biosynthesis, Coumarins, Daphne mezereum, Daphnetin | | | |
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| default:Reihe_C/41/ZNC-1986-41c-0247.pdf | | | | Identifier
| ZNC-1986-41c-0247 | | | | Volume
| 41 | |
| 3 | Author
| J. B. Stothers, A. Stoessl, E.W B Ward | Requires cookie* | | | Title
| | | | | Abstract
| The mechanism of the biological hydroxylation of the isopropenyl side-chain of the sesquiterpene capsidiol, to give 13-hydroxycapsidiol, has been investigated with 13C-N M R techniques, using capsidiol biogenetically enriched with 13C from [l^-^CU] acetate. The results indicate that neither an allylic rearrangement nor the formation of an epoxide intervene in the process. | | | |
Reference
| Z. Naturforsch. 33c, 149—150 (1978); eingegangen am 30. Dezember 1977 | | | |
Published
| 1978 | | | |
Keywords
| Biosynthesis, Capsidiol, 13C-NMR, Phytoalexins, Sesquiterpenes | | | |
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| | | | | TEI-XML for
| default:Reihe_C/33/ZNC-1978-33c-0149_n.pdf | | | | Identifier
| ZNC-1978-33c-0149_n | | | | Volume
| 33 | |
| 4 | Author
| K.H G Rum Bach, B. Fom | Requires cookie* | | | Title
| Chloroplast Autonomy in Acetyl-Coenzyme-A-Formation and Terpenoid Biosynthesis | | | | Abstract
| Isolated intact spinach chloroplasts were supplied with 14C-labeled C 0 2, phosphoglycerate, phos-phoenolpyruvate, acetate and mevalonate and the incorporation o f radioactivity into /?-carotene and plastoquinone-9 assayed. All applied substrates were capable of crossing the chloroplast envelope. Except phosphoenolpyruvate all radioactive precursors were incorporated into ß-carotene and also into plastoquinone-9. It is concluded that spinach chloroplasts are autonom in acetyl-coenzyme-A-formation and terpenoid biosynthesis. There is a direct carbon flow from intermediates of the Calvin-cycle via acetyl-coenzyme-A and mevalonic acid existing in the chlo roplast leading to the carotenoids and isoprenoid side-chains o f chlorophylls and quinones. | | | |
Reference
| Z. Naturforsch. 35c, 645—648 (1980); received March 25 1980 | | | |
Published
| 1980 | | | |
Keywords
| Biosynthesis, /?-Carotene, Chloroplast, Plastoquinone-9, Terpenoids | | | |
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| | | | | TEI-XML for
| default:Reihe_C/35/ZNC-1980-35c-0645.pdf | | | | Identifier
| ZNC-1980-35c-0645 | | | | Volume
| 35 | |
| 5 | Author
| RobleyJ. Light, Klaus Hahlbrock | Requires cookie* | | | Title
| Randomization of the Flavonoid A Ring during Biosynthesis of Kaempferol from |l,2 -,3C2j Acetate in Cell Suspension Cultures of Parsley | | | | Abstract
| Cell suspension cultures o f parsley (Petroselinum hortense) were incubated with [l,2-13C2]ace-tate during a period o f active flavonoid production. The flavonoid glycosides were extracted with ethanol, hydrolyzed in dilute acid, and the aglycones purified by chromatography. Apigenin, a flavone, and kaempferol, a flavonol, were analyzed at 67.9 MHz by 13C FT NMR. The 13C enrich ment confirmed that acetate contributes primarily to the flavonoid A ring. The coupling patterns between adjacent 13C atoms o f the A ring indicate that the cyclization direction of the A ring is random in both compounds. While randomization o f apigenin could have occurred chemically through opening of the pyrone ring under the acid conditions used for glycoside hydrolysis, ran domization o f the more stable flavonol must have occurred biosynthetically. The latter result supports the conclusion that a chalcone is an intermediate in flavonoid biosynthesis. | | | |
Reference
| Z. Naturforsch. 35c, 717—721 (1980); received May 9 1980 | | | |
Published
| 1980 | | | |
Keywords
| 13C-NMR, Apigenin, Kaempferol, Flavonoid, Biosynthesis | | | |
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| default:Reihe_C/35/ZNC-1980-35c-0717.pdf | | | | Identifier
| ZNC-1980-35c-0717 | | | | Volume
| 35 | |
| 6 | Author
| Rainer Sütfeld, Rolf Wiermann | Requires cookie* | | | Title
| Purification of Chalcone Synthase from Tulip Anthers and Comparison with the Synthase from Cosmos Petals | | | | Abstract
| Chalcone synthase was isolated from both anthers of Tulipa cv. "A peldoorn" and petals of Cosmos sulphureus Cav. After certain prepurification steps, the enzymes were further purified using gel chrom atography on Sephadex G-200 followed by repeated hydroxylapatite absorption chromatography. Both the enzymes showed the same chrom atographic properties. After gel chrom atography as well as after the first hydroxylapatite fractionation, the reaction products appeared as flavanones. However, after the second hydroxylapatite step, production of chalcones was observed. Like the enzyme from tulip anthers, the synthase from Cosmos petals produced the correspondingly substituted chalcones when p-coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA, respectively, were used as substractes. In both the cases, the ratios o f the different chalcones produced were found to be about the same. The appearance o f chalcone synthesis in this in vitro assay is caused by the complete elim ination of chalcone isomerase in the purification procedure. The importance of the isomerase for flavonoid biosynthesis, particularly in plant systems which are accumulating chalcones, is discussed. | | | |
Reference
| Z. Naturforsch. 36c, 30—3 (1981); received N ovem ber 12 1980 | | | |
Published
| 1981 | | | |
Keywords
| Tulipa, Cosmos, Biosynthesis, Flavonoids, Chalcone Synthase | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0030.pdf | | | | Identifier
| ZNC-1981-36c-0030 | | | | Volume
| 36 | |
| 8 | 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 | |
| 9 | 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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| default:Reihe_C/36/ZNC-1981-36c-0486_n.pdf | | | | Identifier
| ZNC-1981-36c-0486_n | | | | Volume
| 36 | |
| 10 | Author
| L. Britsch, W. Heller, H. Grisebach | Requires cookie* | | | Title
| Conversion of Flavanone to Flavone, Dihydroflavonol and Flavonol with an Enzyme System from Cell Cultures of Parsley | | | | Abstract
| Soluble enzyme preparations from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.) catalyse the conversion o f flavanone to flavone, dihydroflavonol and flavonol. These reactions require 2-oxoglutarate, Fe2+ and ascorbate as cofactors. In the presence o f these cofactors conversion of dihydroflavonol to flavonol was also observed. With this system in vitro biosynthesis of radioactive flavone, dihydroflavonol and flavonol from [2-14C]malonyl-CoA and 4-coumaroyl-CoA in good yield and with high specific activity is possible. We postulate that synthesis of flavone and flavonol from flavanone proceeds via 2-hydroxy-and 2,3-dihydroxyflavanone, respectively, with subsequent dehydration. The microsomal fraction of the parsley cells contains an NADPH-dependent flavanone 3'-hydroxylase. | | | |
Reference
| Z. Naturforsch. 36c, 742—750 (1981); received June 3 1981 | | | |
Published
| 1981 | | | |
Keywords
| Flavonoids, Biosynthesis, Dioxygenases, Petroselinum hortense, Cell Cultures | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0742.pdf | | | | Identifier
| ZNC-1981-36c-0742 | | | | Volume
| 36 | |
| 11 | Author
| Gary Kuroki, JonathanE. Poulton | Requires cookie* | | | Title
| The Para-O-Methylation of Apigenin to Acacetin by Cell-Free Extracts of Robinia pseudoacacia L | | | | Abstract
| Crude extracts from young Robinia pseudoacacia seedlings, shoots, and callus tissue catalyze the />ara-0-methylation of apigenin to acacetin using S-adenosyl-L-methionine as methyl donor. Optimum activity was exhibited at pH 9.0, and Mg2+ was not required for maximum activity. EDTA (10 m M) did not affect the reaction rate, but 47% inhibition was observed with SAH (100 u m). /?-Mercaptoethanol (5 m M) was required in the homogenization medium for optimum O-methyltransferase activity. Apigenin (K m, 50 hm) was the best substrate, but significant activity was shown towards caffeic acid, 5-hydroxyferulic acid, naringenin, and quercetin. Para-coumaric, ferulic, and sinapic acids were not methylated. The Km for S-adenosyl-L-methionine was 31 hm. Our demonstration o f a /wra-O-methyltransferase activity methylating apigenin, but not /rara-coumaric acid, strongly supports the conclusion that the B-ring methylation pattern of acacetin is determined at the C15-level in Robinia pseudoacacia. | | | |
Reference
| Z. Naturforsch. 36c, 916 (1981); received July 6 1981 | | | |
Published
| 1981 | | | |
Keywords
| Robinia pseudoacacia, Biosynthesis, Flavonoids, Para-O-Methyltransferase, Acacetin | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0916.pdf | | | | Identifier
| ZNC-1981-36c-0916 | | | | Volume
| 36 | |
| 12 | Author
| R. B. Herbert, J. Mann, A. Römer | Requires cookie* | | | Title
| Phenazine and Phenoxazinone Biosynthesis in Brevibacterium iodinum | | | | Abstract
| The source o f nitrogen in the phenazine, iodinin 5, and in 2-aminophenoxazinone 7 in Brevi bacterium iodinum cultures is shown to be primarily from the amide nitrogen of glutamine in ex periments with (S)-[C 015N H 2]glutamine, [15N]ammonium sulphate, and (S)-[15N]glutamic acid. The biosynthesis of 5 and 7 is closely related; biosynthesis o f 7 like that o f 5 diverts from the shi-kimic acid pathway at a stage prior to anthranilic acid 8. | | | |
Reference
| Z. Naturforsch. 37c, 159 (1982); received October 23/December 151981 | | | |
Published
| 1982 | | | |
Keywords
| Phenazines, Phenoxazinones, Biosynthesis, Brevibacterium iodinum, Nitrogen Incorporation | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0159.pdf | | | | Identifier
| ZNC-1982-37c-0159 | | | | Volume
| 37 | |
| 13 | Author
| PaulM. Dewick, M. Elanie, J. Steele, RichardA. Dixon, IanM W Hitehead | Requires cookie* | | | Title
| Biosynthesis of Isoflavonoid Phytoalexins: Incorporation of Sodium |1,2-13C2] Acetate into Phaseollin and Kievitone | | | | Abstract
| 13C-NMR analysis of the isoflavonoid phytoalexins phaseollin and kievitone produced by feeding sodium [l,2-13C2]acetate to wounded bean (Phaseolus vulgaris) cotyledons has demon strated the incorporation of intact acetate units into the aromatic A rings. Phaseollin shows a specific folding of the polyketide chain, whereas kievitone exhibits a randomisation of label in accordance with the intermediacy of a 2',4',6'-trihydroxylated chalcone during its formation. In neither case was sufficient label incorporated into analysis. | | | |
Reference
| Z. Naturforsch. 37c, 363—368 (1982); received February 18 1982 | | | |
Published
| 1982 | | | |
Keywords
| Biosynthesis, 13C-NMR, Phytoalexin, Phaseollin, Kievitone, Isoflavonoid | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0363.pdf | | | | Identifier
| ZNC-1982-37c-0363 | | | | Volume
| 37 | |
| 16 | Author
| Ii Carotinoide, H. Ainfried, E. A. Schenk, H. Arald, S. Transky | Requires cookie* | | | Title
| Der Einfluß von Cycloheximid und Chloramphenicol auf die Biosynthese der Photosynthese-Pigmente in Cyanophora paradoxa Korsch | | | | Abstract
| The Influence o f Cyclohexim ide and C hloram phenicol on the B iosynthesis o f the Photosynthetic Pigm ents in Cyanophora paradoxa. II. C arotenoids M argarete N eu-M üller, To prove the extent to which the endocyanelle o f C. paradoxa is autonom ous with respect to the biosynthesis o f its photosynthetic pigments, the degree, to w hich the translation inhibitors cyclohexim ide (CHI) and chloramphenicol (CA) influence the biosynthesis o f carotenoids, was | | | |
Reference
| Z. Naturforsch. 38c, 984—9 (1983); received July 19 1983 | | | |
Published
| 1983 | | | |
Keywords
| Cyanophora paradoxa, Biosynthesis, /?-Carotene, Zeaxanthin, Chlorophyll | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0984.pdf | | | | Identifier
| ZNC-1983-38c-0984 | | | | Volume
| 38 | |
| 19 | Author
| NigelC P Baldwin, BarrieW. Bycroft, PaulM. Dewick, John Gilbert, Ian Holden | Requires cookie* | | | Title
| Biosynthesis of Trichothecene My cotoxins in Fusarium culmorum Cultures | | | | Abstract
| A high yielding production of the trichothecene mycotoxin 3-acetyldeoxynivalenol (3-AcDON) in cultures of Fusarium culmorum is described. By supplying [14C]acetate, 14C-labelled 3-AcDON suitable for further metabolic studies has been obtained. The pattern of labelling has been ascertained by using 13C-labelled acetate precursors, and is in line with established biosynthetic data. A second trichothecene produced in significant amounts by F. culmorum has been identified as 3a, 15-diacetoxy-7a, 8a-dihydroxy-12, 13-epoxytrichothec-9-ene (7a, 8 a-dihydroxycalonec-trin). | | | |
Reference
| Z. Naturforsch. 40c, 514—518 (1985); received May 8 1985 | | | |
Published
| 1985 | | | |
Keywords
| Mycotoxin, Trichothecene, Fusarium, Biosynthesis, 3-Acetyldeoxynivalenol | | | |
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| | | | | TEI-XML for
| default:Reihe_C/40/ZNC-1985-40c-0514.pdf | | | | Identifier
| ZNC-1985-40c-0514 | | | | Volume
| 40 | |
|
