R. Liardon, Simone Ledermann, U. Ott
Jan 9, 1981
Citations
2
Influential Citations
72
Citations
Quality indicators
Journal
Journal of Chromatography A
Abstract
Abstract A method for the accurate determination of d -amino acids in protein/peptide samples has been developed. This method differentiates d -isomers formed during protein acid hydrolysis from the initial contribution of the sample. To this effect, the hydrolysis is carried out in deuterated hydrochloric acid. Any molecule that is inverted during this step becomes automatically labelled with deuterium. Amino acids are then separated by gas chromatography as N(O,S)-trifluoroacetyl-O-isopropyl esters on a chiral stationary phase and detected by mass spectrometry in selected ion monitoring mode. At present, twelve protein amino acids, including seven essential ones, are monitored in a two-run procedure. This technique allows the determination of the d / l ratio down to 0.1%. Based on this method, the inversion rate constants of fifteen amino acids have been determined under acid hydrolysis conditions (110°C, 6 N 2 HCl). Preliminary data are presented on the racemization induced in protein samples heated in the solid state in the presence of low amounts of water.