MATRIX-ASSISTED LASER DESORPTION IONIZATION MASS-SPECTROMETRY SAMPLE PREPARATION TECHNIQUES DESIGNED FOR VARIOUS PEPTIDE AND PROTEIN ANALYTES/

This study encompasses a collection of experiences with regard to nume rous matrix-assisted laser desorption/ionization mass spectrometry (MA LDI-MS) sample preparation techniques in terms of their suitability fo r different peptide and protein analytes. Variants of both established and new sample preparation techniques for the MALDI-MS analysis of pe ptides and proteins are described. The importance of matrix selection, matrix and analyte concentration, pH adjustment, crystallization cond itions and the use of additives is evaluated. The tolerance of the dif ferent sample preparations towards salts, buffers, synthetic polymers, detergents, denaturants and other contaminants, and also the influenc e of the preparation methods on undesired amino acid side-chain oxidat ion, are investigated. Moreover, the performance of on-target tryptic digestion and on-target disulfide reduction is shown and a microscale purification procedure is described. According to this study, there is no universally applicable sample preparation for a broad variety of a nalytes. Rather, it is necessary to specifically adapt the sample prep aration to the analyte properties. (C) 1997 by John Wiley & Sons, Ltd.