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  • 1
    Electronic Resource
    Electronic Resource
    Absolute configuration for peptidomimetic residues in bioactive peptides (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 268-276 
    Details
    ISSN: 0899-0042
    Keywords: absolute configuration ; peptidomimetics ; retro-inverso modifications ; 2-aminocyclopentanecarboxylic acid ; nuclear magnetic resonance (NMR) ; nuclear Overhauser effect ; bioactive peptides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modern method is reported for the assignment of absolute configuration for peptidomimetics in bioactive peptides by use of 1H-NMR parameters in solution. Four peptide systems incorporating either retro-inverso modifications or 2-aminocyclopentanecarboxylic acid (2-Ac5c) as a peptidomimetic for proline are discussed. (1) Two 14-membered cyclic dermorphin analogs Tyr-c[D-A2bu-Phe-gPhe-(S and R)-mLeu] with a reverse amide bond between gPhe and mLeu residues where gPhe denotes a gem-diamino analog of Phe and mLeu refers to a malonyl analog of Leu. (2) Two cyclic hexapeptides related to somatostatin, c[gSar6-(S and R)-mPhe7-D-Trp8-Lys9-Thr10-Phe11], with a reverse amide bond between the gSar and mPhe residues where the gSar and mPhe denote the gem-diamino and malonyl analogs of the Sar and Phe residues, respectively. The superscript numbers refer to positions in native somatostatin. (3) Cyclic hexapeptide somatostatin analogs containing 2-Ac5c [trans-(1S,2S)-2-Ac5c, trans-(1R,2R)-2-Ac5c, cis-(1R,2S)-2-Ac5c, and cis-(1S,2R)-2-Ac5c] in place of proline c[(2-Ac5c)6-Phe7-D-Trp8-Lys9-Thr10-Phe11]. (4) Morphiceptin related analogs incorporating a cis-2-Ac5c residue as shown in Tyr-cis-2-Ac5c-Phe-Val-NH2. The methodology described in this investigation could be applied to a wide variety of peptide systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030410
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  • 2
    Electronic Resource
    Electronic Resource
    Sweet and bitter taste: Structure and conformations of two aspartame dipeptide analogues (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 1 (1995), S. 349-359 
    Details
    ISSN: 1075-2617
    Keywords: X-ray structures ; conformational analysis ; taste ligands ; peptidomimetics ; sweetener ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and X-ray diffraction analysis of two dipeptide taste ligands have been carried out as part of our study of the molecular basis of taste. The compounds L-aspartyl-D-α-methylphenylalanine methyl ester [L-Asp-D-(αMe)Phe-OMe] and L-aspartyl-D-alanyl-2,2,5,5-tetramethylcyclopentanyl ester [L-Asp-D-Ala-OTMCP] elicit bitter and sweet taste, respectively. The C-terminal residues of the two analogues adopt distinctly different conformations in the solid state. The aspartyl moiety assumes the same conformation found in other dipeptide taste ligands with the side-chain carboxylate and the amino groups formaing a zwitterionic ring with a conformation defined by ψ,χX1 = 157.7°, -61.5° for L-Asp-D-Ala-OTMCP and 151.0°, -68.8° for L-Asp-D-(αMe)Phe-OMe. In the second residue, a left-handed helical conformations is observed for the (αMe)Phe residue of L-Asp-D-(αMe)Phe-OMe with φ2 = 49.0° and ψ2 = 47.9°, while the Ala residue of L-Asp-D-Ala-OTMCP adopts a semi-exextended conformation characterized by dihedral angles φ2 = 62.8° and ψ2 = -139.9°. The solid-state structure of the bitter L-Asp-D-(αMe)Phe-OMe is extended; while the crystal structure of the sweet L-Asp-D-OTMCP roughly adopts the typical L-shaped structure shown by other sweeteners. The data of L-Asp-D-(αMe)Phe-OMe are compared with those of its diastereoisomer L-Asp-L-(αMe)Phe-OMe. Conformational analysis of the two taste ligands in solution by NMR and computer simulations agrees well with our model for sweet and bitter tastes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/psc.310010602
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  • 3
    Electronic Resource
    Electronic Resource
    β,β-Dimethylcyclolanthionines, New Constrained Dipeptide Mimetics: Synthesis, Crystal Structures, and Conformational StudiesWe thank Drs. George Ösapay (UC-Riverside), Yunfei Zhu (Bioresearch Inc.), and Joseph Taulane for helpful discussions. We also thank Dr. Richard Kondrat (UC-Riverside) for mass spectroscopic analyses. This work was supported by the NIH (grant DK-15410).Dedicated to Professor Ivar Ugi on the occasion of his 65th birthday (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 35 (1996), S. 90-92 
    Details
    ISSN: 0570-0833
    Keywords: lanthionines ; peptidomimetics ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199600901
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    Paper (German National Licenses)
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