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  • 1
    Electronic Resource
    Electronic Resource
    Benzylisoquinoline Biosynthesis by Cultivated Plant Cells and Isolated Enzymes (1985)
    s.l. : American Chemical Society
    Journal of natural products 48 (1985), S. 725-738 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50041a003
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  • 2
    Electronic Resource
    Electronic Resource
    An attempt to extract semi-hard QCD effects fromp $$\bar p$$ elastic scattering data (1989)
    Springer
    The European physical journal 43 (1989), S. 651-654 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From a model independent analysis of thep $$\bar p$$ differential elastic cross section at $$\sqrt s = 53$$ and 546 GeV we have tried to extract the semi-hard QCD component in the eikonal. Our conclusions are: 1) the hadronic form factor for semi-hard interaction has a radius slightly smaller than the electromagnetic radius, 〈r 2〉 SH 1/2 =0.66 fm, 2) the total inelastic semi-hard cross section at 546 GeV is σSH ≃ 15mb, not very different from the minijet cross section measured by the UA1 collaboration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01550945
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  • 3
    Electronic Resource
    Electronic Resource
    An extended dynamic keating matrix of the chalcopyrite lattice (1985)
    Springer
    Czechoslovak journal of physics 35 (1985), S. 1346-1354 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Keating model used for the description of the covalent contributions of the crystal bonds in chalcopyrites is extended taking into account the geometrical differences between the chalcopyrite and sphalerite lattices expressed usually by τ = 2 − c0/a0 andx. The resulting matrix elements are given. The results are compared with those of an undistorted lattice by means of the calculation of phonon frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01772716
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  • 4
    Electronic Resource
    Electronic Resource
    Spektrale Momente und Charakteristische Debyefrequenzen von Diamantartigen Halbleiterverbindungen (1985)
    Springer
    Czechoslovak journal of physics 35 (1985), S. 739-751 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Moments of frequency spectrum and Debye characteristic frequencies are taken from literature or are calculated, using the data of specific heat, Debye characteristic temperatures, and mean square atomic displacements of the fourth group elements and compounds with sphalerite structure. The typical features of the Debye characteristic frequencies of these substances are shown and discussed. The results of some theoretical and experimental determinations of latticce dynamical properties of these substances are compared and estimated by means of the dependene of the Debye characteristic frequencies on the order of the moments of frequency spectrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01596186
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  • 5
    Electronic Resource
    Electronic Resource
    Late enzymes of vindoline biosynthesis. Acetyl-CoA: 17-O-deacetylvindoline 17-O-acetyl-transferase (1985)
    Springer
    Plant cell reports 4 (1985), S. 333-336 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From differentiated plants of Catharanthus roseus (L.) G. Don, a specific enzyme was isolated and named acetyl-CoA : 17-O-deacetylvindoline 17-O-acetyltransferase, acting on the biosynthetic formation of the Aspidosperma type alkaloid vindoline. The enzyme shows a high selectivity towards different substrates. The acetyl-CoA-dependent transferase also catalyses the reverse reaction by hydrolysis of the 17-O-acetyl group of vindoline in the presence of free CoA. This enzyme is localized only in vindoline-containing plant parts, but was so far not detectable in cell suspension cultures of C. roseus. The enzyme allows the synthesis of labelled vindoline with high specific activity, applicable for instance as tracer for radioimmunoassays of vindoline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269892
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  • 6
    Electronic Resource
    Electronic Resource
    Late enzymes of vindoline biosynthesis (1985)
    Springer
    Plant cell reports 4 (1985), S. 337-340 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From differentiated plants of Catharanthus roseus (L.) G. Don we have isolated a specific enzyme of the vindoline biosynthetic pathway catalysing the S-adenosylmethionine-dependent methylation of 11-O-demethyl-17-O-deacetyl-vindoline. The enzyme we named S-adenosyl-L-methionine : 11-O-demethyl-17-O-deacetylvindoline 11-O-methyltransferase. This transferase exhibits a high substrate specificity. Obviously the O-methylation at C-11 precedes the O-acetylation at the C-17 position during the biosynthesis of vindoline. A second enzyme was detected which hydrolyses the acetyl function of vindoline. The distribution of this acetylesterase in C. roseus plants demonstrates that the enzyme is not specifically associated with the vindoline distribution in the plant material. Most probably this enzyme plays no essential role in the biosynthesis of vindoline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269893
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  • 7
    Electronic Resource
    Electronic Resource
    Accumulation of alkaloids in plant vacuoles does not involve an ion-trap mechanism (1986)
    Springer
    Planta 167 (1986), S. 44-53 
    Details
    ISSN: 1432-2048
    Keywords: Alkaloid (vacuole, uptake) ; Fumaria ; Compartmentation (alkaloids) ; Stereospecific uptake (alkaloids) ; Vacuole (alkaloid uptake)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alkaloid uptake into vacuoles isolated from a Fumaria capreolata L. cell suspension culture was investigated. The uptake is carrier-mediated as shown by its substrate saturation, its sensitivity to metabolic inhibitors and especially by its exclusive preference for the (S)-forms of reticuline and scoulerine while the (R)-enantiomers which do not occur in this plant species were strictly discriminated. The carrier has a high affinity for (S)-reticuline with a K m=0.3 μM. The rate of alkaloid uptake was 6 pmol·h-1·μl-1 vacuole, and 0.03 mg alkaloid·mg-1 vacuolar protein were taken up. Transport was stimulated five-to seven-fold by ATP and was inhibited by the ATPase inhibitors N,N′-dicyclohexylcarbodiimide and 4-4′-diisothiocyanatostilbene-2,2′ disulfonic acid, as well as by the protonophore carbonyl cyanide m-chlorophenylhydrazone. A number of alkaloids did not compete with labelled (S)-reticuline for uptake into vacuoles. The uptake system is absolutely specific for alkaloids indigenous to the plant from which the vacuoles were isolated. Slight modifications of the topography of an alkaloid molecule even with full retention of its electrical charge results in its exclusion. Alkaloid efflux was also shown to be mediated by a highly specific energy-dependent carrier. These results contradict the previously proposed ion-trap mechanism for alkaloid accumulation in vacuoles. A highly specific carrier-mediated and energy-dependent proton antiport system for alkaloid uptake and release is postulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446367
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  • 8
    Electronic Resource
    Electronic Resource
    Disproof of the Overall Enzymatic Biosynthesis of Vindoline from Tryptamine and Secologanin by Cell-Free Extracts from the Leaves of Catharanthus roseus (L.) G. DON (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 315-318 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A cell-free extract, which was isolated from the leaves of mature Catharanthus roseus plants by a previously published procedure, does not convert a mixture of secologanin and radiolabelled tryptamine to vindoline, as was recently claimed. The radioactivity in the purified alkaloid extract determined by earlier workers is certainly due to ‘impurities’ in the presumed ‘vindoline’. This was shown by extensive purification of the alkaloid extract (which contained added unlabelled vindoline as a carrier) followed by chemical conversion of vindoline to two derivatives and subsequent purification, ultimately giving unlabelled deacetylvindoline.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680204
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