APPLICATION OF ELECTROSPRAY MASS-SPECTROMETRY AND MATRIX-ASSISTED LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY FOR MOLECULAR-WEIGHT ASSIGNMENT OF PEPTIDES IN COMPLEX-MIXTURES

Electrospray mass spectrometry (ES/MS) and matrix-assisted laser desor ption ionization time-of-flight mass spectrometry (MALDI/TOF/MS) were used to provide mass spectra from seven elapid snake venoms. Spectral interpretation was much simpler for MALDI/TOF/MS. ES/MS proved more us eful for the provision of molecular weight data for very closely relat ed peptides, but suppression of higher molecular weight compounds was seen to occur during flow injection analysis. MALDI/TOF/MS proved usef ul for providing a complete picture of the venom, but the low resoluti on led to obscuring of major ions, and the mass accuracy was poorer fo r known peptides. Suppression also occurred during MALDI/TOF/MS but co uld be overcome using alternative matrices because the spectra were ve ry dependent on the choice of matrix. ES/MS and MALDI/TOF/MS provide c omplementary and confirmatory information such that for the analysis o f complex peptide mixtures (snake venoms), the use of both techniques is desirable.