title: Association of model peptides and dehydropeptides: N-acetyl-L-butyrine and (Z)-dehydrobutyrine N',N'-dimethylamides.
abstract: These comparative studies on the aggregation behaviour of Ac-(Z)-DeltaAbu-NMe(2) and Ac-L-Abu-NMe(2) in carbon tetrachloride were performed by the analysis of their FTIR spectra and by theoretical calculations. The percentage of the monomeric form (alpha) decreased as concentration increased and this occurred to a higher degree for the (Z)-DeltaAbu derivative than for its saturated analogue. The dimerization constant K(D), calculated on the basis of the intensity of the monomer and associate bands in the nu(s)(N-H) vibration region, is by three orders of magnitude larger for Ac-(Z)-DeltaAbu-NMe(2) than for Ac-L-Abu-NMe(2). The obtained dimer geometries of the dehydro- compound were calculated by the B3LYP/6-31+G** method.
authors.affiliation: Institute of Chemistry, University of Opole, Opole, Poland.
authors.forename: Małgorzata A
authors.initials: MA
authors.lastname: Broda
authors.forename: Barbara
authors.initials: B
authors.lastname: Rzeszotarska
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000613:Aminobutyrates / Q000737:chemistry*; D019281:Dimerization; D004151:Dipeptides / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D008956:Models, Chemical; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000596:Amino Acids; D000613:Aminobutyrates; D004151:Dipeptides; C515310:N-acetylbutyrine N',N'-dimethylamide; D010455:Peptides; C515311:dehydrobutyrine N',N'-dimethylamide; C012223:alpha-aminobutyric acid