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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 43 (1997), S. 219-266 
    ISSN: 0006-3525
    Keywords: peptides ; proteins ; peptidomimetics ; chi space ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Peptide and protein biological activities depend on their three dimensionals structures in the free state and when interacting with their receptors/acceptors. The backbone conformations such as α-helix, β-sheet, β-turn, and so forth provide critical templates for the three-dimensional structure, but the overall shape and intrinsic stereoelectronic properties of the peptide or protein important for molecular recognition, signal transduction, enzymatic specificity, immunomodulation, and other biological effects depend on arrangement of the side chain groups in three-dimensional chi space (their χ1, χ2, etc. torsional angles)In this paper we explore approaches to the de novo design of polypeptides and peptidomimetics with biased or specific conformational/topographical properties in chi space. We consider computational and experimental methods that can be used to examine the effects of specific structural modifications in constraining side chain groups of amino acid residues and their similarities in chi space to the natural amino acids to evaluate what sort of mimetics are likely to minic normal amino acids. We then examine some of the asymmetric synthetic methods that are being developed to obtain the amino acid mimetics. Finally, we consider selected examples in the literature where these specialized amino acids have been incorporated in biologically active peptides and the specific insights they have provided regarding the topographical requirements for bioactive peptide potency, selectivity, and other biochemical and pharmacological properties. Constraints in chi space show great promise as useful tools in peptide, protein, and peptidomimetic de novo design of structures and pharmacophores with specific stereostructural, biochemical and biological properties. © 1997 John Wiley & Sons, Inc. Biopoly 43: 219-266, 1997
    Additional Material: 21 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1213-1217 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelektronenspektren, elektronische Struktur und Gasphasenthermolyse von substituierten TetrazolinenDie elektronische Struktur und die Gasphasenthermolyse der Tetrazoline 1-5 wurden durch Photoelektronenspektroskopie untersucht. Die Verbindungen 1-4 zerfallen durch Cycloreversion in Methylazid und die entsprechenden Imine. Demgegenüber wird aus 5 unter Ringkontraktion ein Diaziridin gebildet. Zur Zuordnung der PE-Spektren wurden an den Verbindungen 1, 2, 4 und 5 MNDO-Rechnungen, zur Konformationsanalyse von 5 auch AM1-Rechnungen durchgeführt.
    Notes: The electronic structures and the gas-phase thermolyses of tetrazolines 1 -5 have been studied by photoelectron spectroscopy. For compounds 1-4 cycloreversion to imine and methyl azide is observed, whereas compound 5 is contracted to give the respective diaziridine. To assign the PE spectra, MNDO calculations were performed for compounds 1, 2, 4, and 5; some conformational properties of 5 have also been studied by AM 1 calculations.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 225-234 
    ISSN: 0935-6304
    Keywords: Tunable column ensembles ; high speed GC ; comprehensive two-dimensional GC ; time of flight ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A series-coupled ensemble of two capillary GC columns of different selectivity with an adjustable pressure at the column junction point is used to obtain tunable selectivity for high-speed GC and GC/TOFMS. An electronic pressure controller with a 0.1-psi step size is used to obtain numerous computer-selected unique selectivities. System configurations for conventional, atmospheric-pressure outlet operation with flame ionization detection and for vacuum-outlet operation with photoionization detection are described for GC-only experiments. Polydimethylsiloxane is used as the non-polar column and polyethylene glycol (atmospheric outlet) or triflouropropylpolysiloxane (vacuum outlet) is used as the polar column. For GC/TOFMS experiments, 5% phenyl polydimethylsiloxane was used as the non-polar column, and polyethylene glycol was used as the polar column. The time-of-flight mass spectrometer can acquire up to 500 complete mass spectra per second. Since spectral continuity is achieved across the entire chromatographic peak profile, severely overlapping peaks can be spectrally deconvoluted for high-speed characterization of completely unknown mixtures. For mixture components with significantly different fragmentation patterns, spectral deconvolution can be achieved for chromatographic peak separations of as little as 6.0 ms. This can result is very large peak capacity for time compressed (not completely resolved) chromatograms. The use of columns with tunable selectivity allows for precise peak-position control, which can result in more efficient utilization of available peak capacity and thus further time compression of chromatograms. The limits of tunability and deconvolution are tested for near co-elutions of different classes of hydrocarbon compounds as well as for more multi-functional mixtures.
    Additional Material: 9 Ill.
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  • 4
    ISSN: 0884-3996
    Keywords: Bioluminescence ; immunoassay ; progesterone ; monoclonal antibodies ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Bacterial luciferase, NAD(P): FMN oxidoreductase and anti-mouse immunoglobulin were co-immobilized on Sepharose 4B. This reagent together with a progesterone glucose-6-phosphate dehydrogenase conjugate and various anti-progesterone monoclonal antibodies was used to develop a non-separation bioluminescent immunoassay for progesterone. This monoclonal antibody based assay was sensitive and reliable and using the tracer progesterone-11-acetate-glucose-6-phosphate dehydrogenase, the majority of the monoclonal antibodies give a better sensitivity with this enzymatic tracer than that obtained with an iodinated tracer.In a second assay design progesterone-glutathione was co-immobilized with bacterial luciferase and NAD(P): FMN oxidoreductase on Sepharose 4B and three monoclonal antibodies were labelled with glucose-6-phosphate dehydrogenase. With aqueous progester-one standards, this assay gave comparable sensitivity to the bioluminescent enzyme immunoassay using the second antibody immunoadsorbant and to an RIA but was unsuitable for plasma samples.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 143-144 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 5 (1994), S. 513-518 
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variety of diazo compounds was added to the parent vinylboronic ester derived from pinacol. The reactivity of some substituted 1-alkenylboronic esters is also briefly examined. The nonisolated primary adducts spontaneously rearrange via a 1,3-boron migration and lead to 1-borylated-2-pyrazolines. The structure of one of these compounds has been established by X-ray diffraction analysis.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electroanalysis 9 (1997), S. 1273-1277 
    ISSN: 1040-0397
    Keywords: Cyclic voltammetry ; Porphyrins ; Silicon ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclic voltammetry was used to characterize the oxidation-reduction behavior of a series of novel hexacoordinate silicon(IV) porphyrin complexes. Each (Por)SiX2 [Por = the dianions of the porphyrins: tetrakis(p-tolyl)porphyrin (TTP), tetraphenylporphyrin (TPP), tetrakis(p-trifluoromethylphenyl)porphyrin (TTFP), octaethylporphyrin (OEP), × = F, Cl, O3SCF3] complex undergoes one to two oxidations and one to two reductions, all occurring at the porphyrin ring. No silicon(IV) reduction is observed for any of the porphyrin complexes. The effects of solvent, supporting electrolyte, substituents on the porphyrin ring, axial ligands, certral metal, and ruffling of the porphyrin ring are described.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1987), S. 121-122 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 24 (1989), S. 909-916 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main fragmentation pathway of ionized hydroxyallenes (1) consists of a methyl loss. Extensive deuterium-labelling experiments indicate that the terminal allenic carbon is implied in this fragmentation. Collisional activation spectra indicate a propenyl-acylium structure (a) for these [M - CH3]+ ions which can originate from a 1,4-hydroxyl migration followed by hydrogen rearrangements. Isomeric hydroxyacetylenes (2) behave similarly, also giving rise, by methyl loss, to acylium ions a. It is proposed that 2+ · is irreversibly isomerized into 1+ · by a 1,3-hydrogen transfer ‘catalysed’ by the hydroxy group. The proposed internal proton-bound complex justifies also the easier loss of water from 2+·. Ethyl loss is also a prominent fragmentation for the hydroxyallene and hydroxy-acetylene homologues.
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 5 (1973), S. 453-457 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational analysis of 1-pyrazolines bearing different substituents on carbons 3 and 4 has been achieved by NMR. The use of the Karplus equation to explain the values of the coupling constants 3J(H4—H5) allows us to ‘check’ the existence of an equilibrium between two envelope conformations. The folding angle of the envelope, calculated on a model compound which is held in only one conformation, wad found to be near 36°. The ratio of the two conformers at room temperature is calculated for the various pyrazolines studied.
    Notes: L'analyse conformationnelle de pyrazolines-1 diversement substituées sur les carbones 3 et 4 a été réalisée à l'aide de la RMN. L'utilisation de l'équation de Karplus pour interpréter les valeurs des constantes de couplage 3J(H4—H5) permet de vérifier l'existence d'un équilibre entre deux formes enveloppes. L'angle d'ouverture de l'enveloppe, calculé sur un composé modèle figé dans une seule conformation, est voisin de 36°. Les pourcentages relatifs des deux conformères à la température ambiante sont calculés pour les divers pyrazolines étudiées.
    Additional Material: 5 Ill.
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