Peptide-mass profiles of polyvinylidene difluoride-bound proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in the presence of nonionic detergents.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), in conjunction with enzymatic digestion of proteins and molecular weight search of peptide-mass database is a powerful technique for peptide/protein identification. Ideally, peptide mixtures should be compatible with both MALDI-TOF and microsequencing. In our laboratory, enzymatic digestion and extraction of peptides from polyvinylidene difluoride (PVDF)-bound proteins is performed in the presence of nonionic detergents. However, nonionic detergents have been shown to cause signal suppression in MALDI-TOF analysis. This study demonstrates that by using a modified matrix solution, peptide-mass fingerprinting of PVDF-bound proteins by MALDI-TOF can be obtained in the presence of nonionic detergents such as hydrogenated Triton X-100 (RTX-100), octylglucopyranoside, and Tween 20.