43135-06-4Relevant articles and documents
Oxidative Damage in Aliphatic Amino Acids and Di- and Tripeptides by the Environmental Free Radical Oxidant NO3?: the Role of the Amide Bond Revealed by Kinetic and Computational Studies
Nathanael, Joses G.,Wille, Uta
, p. 3405 - 3418 (2019/03/11)
Kinetic and computational data reveal a complex behavior of the important environmental free radical oxidant NO3? in its reactions with aliphatic amino acids and di- and tripeptides, suggesting that attack at the amide N-H bond in the peptide backbone is a highly viable pathway, which proceeds through a proton-coupled electron transfer (PCET) mechanism with a rate coefficient of about 1 × 106 M-1 s-1 in acetonitrile. Similar rate coefficients were determined for hydrogen abstraction from the α-carbon and from tertiary C-H bonds in the side chain. The obtained rate coefficients for the reaction of NO3? with aliphatic di- and tripeptides suggest that attack occurs at all of these sites in each individual amino acid residue, which makes aliphatic peptide sequences highly vulnerable to NO3?-induced oxidative damage. No evidence for amide neighboring group effects, which have previously been found to facilitate radical-induced side-chain damage in phenylalanine, was found for the reaction of NO3? with side chains in aliphatic peptides.
Synthesis of N-alkyl-Cα,α-dimethylglycine derivatives
Monteiro, Luis S.,Pereira-Lima, Silvia M.M.A.,Pereira, Sofia,Machado, Joao N.
, p. 170 - 180 (2014/10/15)
The application of trialkyloxonium tetrafluoroborates for N-alkylation of the nonnatural amino acid Cα, α-dimethylglycine is described. Several methyl esters of dimethylglycine protected with different amine protecting groups were subject to N-
SYNTHESE VON 2-METHYLALANIN-PEPTIDEN, DIE pH-ABHAENGIGKEIT IHRER 13C-NMR-SPECTREN UND EINE NEUE METHODE ZUR AUSWERTUNG UEBER CS-DIAGRAMME
Leibfritz, Dieter,Haupt, Erhard,Dubischar, Norbert,Lachmann, Heinrich,Oekonomopulos, Raymond,Jung, Guenther
, p. 2165 - 2182 (2007/10/02)
The uncommon amino-acid 2-methylalanine (α-aminoisobutiryc acid, Aib) was investigated by 13C-NMR.The chemical shifts of amino- or carboxy-protected derivates of Aib and of protected oligopeptides are discussed with respect to neighbouring groups and amino acids.The pH-dependence of the 13C-NMR spectra of Aib, Aib-Ala, Ala-Aib, Aib-Ala-Aib and Aib-Ala-Aib-Ala-Aib was studied.Using these examples, a new and advantageous method is demonstrated for the first time for the evaluation of NMR titration curves, which uses so-called chemical shift diagrams (CS diagrams).