NANOGRAM SCALE SEPARATIONS OF PROTEINS USING CAPILLARY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FULLY-AUTOMATED ONLINE MICROFRACTION COLLECTION FOLLOWED BY MATRIX-ASSISTED LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY, PROTEIN SEQUENCING AND WESTERN-BLOT-ANALYSIS

Capillary HPLC was applied for highly sensitive protein separations on a nanogram scale. A crude extract of acid soluble proteins from maize kernels was used as a model extract and separated on a 300-mu m I.D. reversed-phase capillary column. Protein fractions of 1-4 mu l volume were fully automatically collected with a new robot microfraction coll ection system. Fraction collection was performed onto matrix assisted laser desorption ionisation time-of-flight targets for mass spectromet ric analysis, onto sequencing membranes for automated Edman degradatio n and onto nitrocellulose membranes for Western blot analysis. (C) 199 8 Elsevier Science B.V.