Characterization of peptides from Aplysia using microbore liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry guided purification

Liquid chromatography (LC) has been used extensively for the separation and isolation of peptides due to its high selectivity and peak capacity. An ap proach combining microbore LC with matrix-assisted laser desorption/ionizat ion time-of-flight mass spectrometry (MALDI-MS) detection is described to i dentify peptides in cells and guide the purification of peptides from the m arine mollusc Aplysia californica. Direct MALDI-MS of neurons acid processe s provides molecular mass information for unknown peptides with almost no s ample preparation, and LC-MALDI-MS allows the isolation and purification of these peptides from pooled samples, thus enabling new putative neuropeptid es to be isolated from complex cellular samples. Both direct MALDI-MS and L C-MALDI-MS an compared in terms of detecting peptides from neuronal samples . Using both approaches, two peaks from Aplysia californica connectives hav ing molecular masses of 5013 and 5021 have been isolated, partially sequenc ed and identified as novel collagen-like peptides. (C) 1999 Elsevier Scienc e B.V. All rights reserved.