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  • 11
    ISSN: 1075-2617
    Keywords: Neuropeptide Y ; centrally truncated analogues ; Y1 receptor binding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four sets of centrally truncated analogues of neuropeptide Y have been synthesized. In each series the N-terminal part was constant, while the C-terminal segment was systematically varied in length. The C- and N-terminal parts were linked by 6-aminohexanoic acid. The affinity to the Y1 receptor was investigated on human neuroblastoma cells SK-N-MC. Significant differences were found between the series of peptides as well as within each set. Remarkably, the affinity did not solely depend on the length of the segment, and with increasing numbers of residues the IC50 values were not always decreased. With a given N-terminal segment, only one optimal length of the C-terminal segment was found, which suggests that it is not the amino acids themselves but their 3D arrangement and orientation that is important for high receptor affinity.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 0170-2041
    Keywords: Lantibiotics ; Circular dichroism ; Gallidermin ; Percursor proteins ; Conformation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to investigate the conformational properties of the precursor proteins of lanthionine-containing bacteriocins we synthesized the leader peptides of the pre-lantibiotics of gallidermin, epidermin, Pep5, nisin, subtilin, the C-terminal 30-mer segment of pre-cinnamycin, propeptide segments of Pep5 and gallidermin and the complete pre-gallidermin, which consists of 52 residues. The peptides were synthesized in a step-by-step synthesis by the Fmoc/tBu strategy using an optimized procedure for the synthesis of large peptides. All peptides were analyzed by HPLC and characterized by electrospray mass spectrometry and amino acid analysis. Circular dichroism spectra exhibited strong α-helical Cotton effects even at a low concentration of trifluoroethanol for all N-terminal leader peptides. Comparative investigations of the C-terminal propeptide segments led to a model of the conformation of the prepeptides of Pep5 and gallidermin in aqueous and lipophilic environments. In addition, circular dichroism investigations on the synthetic precursor protein of gallidermin and the isolated natural pre-Pep5 were performed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 0170-2041
    Keywords: Cyclization methods ; Neuropeptide Y ; Coupling reagents ; Cyclopeptide ; Peptide synthesis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The short-cut analog of neuropeptide Y (NPY), NPY 1YESK-Ahx-25RHYINKITRQRY-NH2, was synthesized on the amide anchor 5-(4-aminomethyl-3,5-dimethoxyphenoxy)valeric acid (ADPV) attached to polystyrene/1% divinylbenzene by using the 9-fluorenylmethoxycarbonyl/tert-butyl (Fmoc/tBu) strategy. Side-chain-to-side-chain cyclization of residues Glu2 to Lys30 of this linear heptadecapeptide amide was carried out by using different activating reagents under high-dilution conditions of the free peptide. The use of diphenylphosphoryl azide (DPPA) with the addition of triethylamine gave the highest yield of cyclic peptide. Replacing the tertiary amine by dipotassium hydrogen phosphate as an insoluble inorganic base did not improve the cyclization. Complete cyclization was achieved within four hours by using 2-(1H-benzotriazol-1-yl) -1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) in combination with 1-hydroxybenzotriazol (HOBt) as activating agent, but the separation from excess TBTU resulted in lower yields. Reactions were monitored by HPLC and kinetic investigations were made. The identity and purity of the final product were proven by various analytical methods including atmospheric pressure ionization mass spectrometry (API-MS). The receptor binding constant of the cyclic analog was found to be comparable to that of NPY.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 0570-0833
    Keywords: Combinatorial chemistry ; Peptide synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rapid developments in the biotechnology of new proteins, as well as advances in immunology and the development of pharmaceuticals based on inhibitors and antagonists, have led to immense demands for synthetic peptides. Simultaneous preparation of 100-150 completely different peptides, having chain lengths of up to 20 amino acids can nowadays be achieved using multiple synthesis methods. The yields and qualities of the peptides so obtained are high enough to permit reliable in vivo and in vitro screening for biological activities. Moreover, it is possible to optimize synthetic conditions and to carry out comparative studies on the secondary structures and conformational mapping of proteins. Special multiple synthesis methods facilitate the epitope mapping of larger peptides for diagnostic purposes and for the development of vaccines based on a few hundreds of free or rod-bound peptides that are useful for immunoassays. Multiple methods of peptide synthesis also enable the preparation of so-called peptide libraries which could comprise hundreds of thousands of peptides, and by which new perspectives for the screening of lead structures will be opened up. Peptide synthesis using a combination of photolabile protecting groups and photolithographic procedures enables the assembling of peptide libraries on small plates for use in miniature immunoassays. Furthermore, lipopeptide-antigen conjugates allow both the preparation of peptide-specific and monoclonal antibodies as well as a complete screening of epitopes of B-, T-helper and T-killer cells. Applications in the areas of AIDS diagnosis, the development of vaccines, and screening for the hormone analogues, demonstrate just some of the possibilities that have been opened up by multiple peptide synthesis methods.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 17
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die rasch fortschreitende Entwicklung in der Biotechnologie neuer Proteine, in der Immunologie und in der auf Inhibitoren und Antagonisten basierenden Pharmaforschung führen zu einem immensen Bedarf an synthetischen Peptiden. Durch multiple Methoden können heute 100-150 völlig verschiedene Peptide mit Kettenlängen bis etwa 20 Aminosäuren gleichzeitig hergestellt werden. Die erzielten Ausbeuten und Qualitäten reichen aus, um ein verläßliches Screening auf biologische Aktivität in vitro und in vivo durchzuführen; dasselbe gilt für Syntheseoptimierungen, Sekundärstrukturvergleiche und Konformationskartierungen. Mit speziellen multiplen Methoden gelingt die Epitopkartierung auch größerer Proteine zur Diagnostik und Impfstoffentwicklung anhand von einigen hundert freien oder an Stäbchen gebundenen Peptiden, die für Immunoassays einsetzbar sind. Multiple Methoden der Peptidsynthese ermöglichen auch den Aufbau von sogenannten Peptidbibliotheken. Diese können Hunderttausende von Peptiden umfassen, wodurch sich neue Perspektiven für das Screening nach Leitstrukturen eröffnen. Mit einer speziellen Peptidsynthese, die die Verwendung von photolabilen Schutzgruppen und photolithographischen Verfahren kombiniert, können Peptidbibliotheken auf Plättchen für miniaturisierte Immunoassays aufgebaut werden. Lipopeptid-Anti-gen-Konjugate, die komplette Proteinsequenzen aus überlappenden Peptidsegmenten umfassen, machen die Herstellung peptidspezifischer und monoklonaler Antikörper sowie ein gezieltes Screening auf Epitope von B-, T-Helfer- und T-Killer-Zellen möglich. Anwendungen auf dem Gebiet der AIDS-Diagnostik, der Impfstoffentwicklung, oder dem Screening nach Hormonanaloga demonstrieren die Perspektiven, die sich durch die multiplen Synthesemethoden eröffnen.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 0960-894X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 0960-894X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: C-terminal analogues of neuropeptide Y (NPY) of small molecular size have been synthesized. The influence of chain length, single or multiple amino acid substitution, and segment substitutions on receptor binding, pre- and postsynaptic biological activity, and conformational properties have been investigated. Receptor binding and in vivo assays revealed biological activity for NPY Ac-25-36 that increased with increasing α-helicity. In attempts to stabilize the α-helical content, three independent types of modified NPY Ac-25-36 analogues were synthesized. Strong agonistic activities could be detected in a series of discontinuous analogues, which are constructs of N-terminal parts linked via different spacer molecules to C-terminal segments. One of the most active molecules was NPY 1-4-Aca-25-36 (Aca, ε-aminocaproic acid). For the first time conformational properties of a series of small NPY analogues have been investigated by CD, and correlated with biological activity and receptor binding. A C-terminal dodecapeptide segment of NPY with an amount of 50% substitution to the native C-terminal sequence of NPY was found to exhibit significant receptor binding.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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