Investigation of polyethylene membranes as potential sample support for linking SDS-PAGE with MALDI-TOF MS for the mass measurement of proteins

Detection of Bacteriocins by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

“…In our studies, a sterile water wash was chosen as the method for removing contaminants. Other researchers have suggested the use of polyethylene or polypropylene membranes for use as activated membranes to which the peptide or protein binds (4,5,26). However, Joosten and Nuñez (15) report that Tween 80 prevents adsorption of the bacteriocins nisin and enterocin on polypropylene surfaces.…”

“…Generally, MALDI-TOF MS involves ion formation using a pulsed UV laser beam to deposit energy into a cocrystallized matrix-analyte sample and ejection of the sample into a vacuum for desorption analysis. The major advantages of MALDI-TOF MS over other mass spectrometric techniques are (i) its ease of use, (ii) its picomole-to-femtomole sensitivity (22), (iii) its high-mass (Ͼ200,000-Da) range and ability to give molecular mass values with a reported accuracy of Ϯ0.1% or better (4,5,7,22), and (iv) its relative tolerance to contaminants in the sample (5,24,25,27). These advantages make MALDI-TOF MS technology suitable for the analysis and characterization of bacteriocins.…”

“…MALDI-TOF MS has been used routinely for the analysis of synthetic peptides and proteins. However, the analysis of peptides and proteins extracted from biological sources has been hampered by the presence of contaminants, such as salts, glycerol, and detergents (1,4,5,18,26,27). These contaminants may suppress the peptide and protein signals completely.…”

“…Researchers have investigated the use of activated synthetic membranes as an alternative to stainless steel in MALDI-TOF MS analysis. By spotting a sample onto a membrane such as polyethylene, contaminants can be washed away, leaving the peptides and proteins intact at the surface for analysis (4,5,26). This process results in equal or greater sensitivity and mass resolution for all samples compared to those desorbed from stainless steel.…”

“…This process results in equal or greater sensitivity and mass resolution for all samples compared to those desorbed from stainless steel. Synthetic membranes are particularly suitable for high-mass (i.e., Ͼ30,000-Da) molecules because severe ion suppression is typically observed in the analysis of high-mass mixtures (4,5). Other researchers have used or suggested further processing of the sample on the probe, such as a wash with cold water to remove the contaminants (18,24,27).…”