MULTIPLE SEQUENTIAL FRACTION COLLECTION OF PEPTIDES AND GLYCOPEPTIDESBY HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS

Multiple sequential fraction collection of peptides and glycopeptides by high-performance capillary electrophoresis (HPCE) under applied vol tage has been demonstrated from complex tryptic peptide maps. The coll ection methodology was adapted from a high-resolution glycopeptide map ping procedure and, as such, requires active temperature control of th e sample, electrophoresis vials, and collections vials because the ele ctrophoresis buffer system is highly conductive. Resolution was compro mised in the preparative HPCE separation due to heavy sample loading a nd to reduced voltage. The latter was a requirement for this buffer sy stem in order to control Joule heating at the current levels employed; collections were routinely performed at approximately 1.5 W/m. The co llection buffer was optimized by the addition of 12% methanol (v/v), t hereby improving collection yields. Tryptic non-glycopeptides were gro up collected; secondary analysis of the HPCE collections agreed with a nalytical separations with respect to the number of peptides contained in a given fraction. Sequentially collected peptide fractions were an alyzed by Edman sequencing and MALDI mass spectrometry to verify pepti de identity and sequence, Consistent peptide sequence or mass measurem ents were obtained for repeat collections. The isolation of the single pure glycopeptide indicates that unique glycopeptide structures can b e collected by HPCE and then analyzed by other methods. (C) 1995 Acade mic Press, Inc.