Peptide mapping of proteins in cerebrospinal fluid utilizing a rapid preparative two-dimensional electrophoretic procedure and matrix-assisted laser desorption/ionization mass spectrometry

A quick two-step procedure involving liquid phase isoelectric focusing in t he Rotofor cell in combination with electroelution in the Mini whole cell g el eluter has been used for purification of proteins from human cerebrospin al fluid (CSF). Fractions, each highly enriched in a single protein band an d virtually free of other proteins, were selected for characterization by m atrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOFMS). Sis CSF proteins, transferrin, alpha 1-acid-glycoprotein, Zn-alpha 2-glyco protein, apolipoprotein Al, apolipoprotein E and beta-trace were identified by MALDI-TOFMS analysis of the tryptic digests. These results demonstrate that the combination of liquid phase IEF and electroelution is a rapid prep arative two-dimensional separation which can provide single proteins of hig h purity, in yields sufficient for characterization by MALDI-TOFMS. Charact erization of such brain-specific proteins in CSF will be useful in the inve stigation of the pathophysiology of different brain disorders. (C) 1999 Els evier Science B.V. All rights reserved.