Identification of Proteins by Combination of MALDI-TOF Peptide Mass Fingerprinting and Fragmentation of Sulfonated Peptides

Abstract

The MALDI TOF MS is an ideal method for routine identification of proteins separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). However, in some cases the outputs from peptide mass fingerprinting (PMF) do not enable unambiguous identification of proteins. In such situation, determination of a partial amino acid sequence of the target protein would be extremely helpful in the PMF identification. Sequencing using MALDI TOF post-source decay (PSD) usually generates complex spectra and the fragmentation is not complete. PSD sequencing with chemically assisted fragmentation allows to avoid these problems. Application of both methods in identification of proteins of Francisella tularensis is presented.