Many quantitative
proteomics methods rely on protein and peptide labeling with stable isotopes. We have recently found that the introduction of
15N into organisms via
in vivo metabolic labeling affects protein expression levels as well as metabolic pathways and behavioral phenotypes. Here, we present further evidence for a stable isotope effect based on the plasma proteome analysis of
15N-labeled mice. We compared plasma proteomes of
15N-labeled and unlabeled (
14N) mice by quantitative MS. We found a number of protein level differences, some of which were verified immunochemically. In addition, we observed divergent chromatographic retention time and peak full width at half maximum (FWHM) between
15N-labeled and
14N tryptic peptides. Our data point toward a systemic effect of the introduction of heavy isotopes
in vivo.
This article is part of a Special Issue entitled: New Horizons and Applications for Proteomics [EuPA 2012].