MATRIX-ASSISTED-LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY ANALYSIS OF PROTEINS IN HUMAN CEREBROSPINAL-FLUID/

Matrix-assisted laser desorption/ionization time-of-flight mass spectr a of proteins in cerebrospinal fluid analyzed without prior purificati on are presented. Less than 100 fmol amounts of proteins in the 10 000 to 20 000 u mass range and linked to human disease (multiple sclerosi s, Alzheimer's disease, and stroke) were detected in a complex mixture of proteins and peptides, in the presence of high concentrations of s alts, lipids and free amino acids. The mass resolution was sufficient to distinguish between the non-hydroxylated and hydroxylated forms of a 13 400 u protein. Simple fractionation of the cerebrospinal fluid us ing microbore-reversed phase high performance liquid chromatography im proved signal-to-noise ratios in the mass spectra. High-accuracy pepti de mass mapping and database searching were utilized to confirm the id entity of several proteins. The presented results show that matrix-ass isted. laser desorption/ionization time-of-flight mass spectrometry co uld be used as a tool to perform rapid screening of chemically altered proteins in small volumes of biological fluids. (C) 1998 John Wiley & Sons, Ltd.