Investigating quantitation of phosphorylation using MALDI-TOF mass spectrometry.

ABSTRACT: Despite advances in methods and instrumentation for analysis of phosphopeptides using mass spectrometry, it is still difficult to quantify the extent of phosphorylation of a substrate because of physiochemical differences between unphosphorylated and phosphorylated peptides. Here we report experiments to investigate those differences using MALDI-TOF mass spectrometry for a set of synthetic peptides by creating calibration curves of known input ratios of peptides/phosphopeptides and analyzing their resulting signal intensity ratios. These calibration curves reveal subtleties in sequence-dependent differences for relative desorption/ionization efficiencies that cannot be seen from single-point calibrations. We found that the behaviors were reproducible with a variability of 5-10% for observe

SUBMITTER: Parker L 

PROVIDER: S-EPMC2874747 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature