title: Applications of ammonium formate-catalytic transfer hydrogenation. Part V (1). Transfer hydrogenolysis of peptides containing p-chlorophenylalanine as a convenient method for preparation of deuterium labeled peptides.
abstract: Dehalogenation of chlorine bound to aromatic nuclei has been achieved using ammonium formate-catalytic transfer hydrogenation (AF-CTH) techniques. The use of deuterated ammonium formate as the transfer agent in the CTH process when performed in a deuterated solvent medium results in the predominant formation of the labeled product. Thus, ND+4 DCOO(-)-CTH of [D-Ala2, p-ClPhe4]-Leu-enkephalin in 80% CD3COOD/D2O yielded [D-Ala2, Phe (4D)4]-Leu-enkephalin. Levels of D-incorporation were measured by fast atom bombardment-mass spectrometry (FAB-MS) and/or by 13C n.m.r. spectroscopy. Using D-labeled and unlabeled ammonium formate in stoichiometrically similar reactions, it was concluded that the hydrogenation exhibited a primary kinetic isotope effect. Reactant and product concentrations were determined by amino acid analysis and reversed phase HPLC.
mesh_terms: D003903:Deuterium; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives*; D010134:Fenclonine; D005561:Formates; D006865:Hydrogenation; D007202:Indicators and Reagents; D007553:Isotope Labeling / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009842:Oligopeptides / Q000138:chemical synthesis*
chemical_list: D005561:Formates; D007202:Indicators and Reagents; D009842:Oligopeptides; C030544:formic acid; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; C054827:enkephalin-Leu, (Ala(2)-Cl-Phe(4))-; D003903:Deuterium; D010134:Fenclonine