Improved MS-based proteomics by the reduction of isotopic composition in vivo

Reducing the isotopic composition of proteins in vivo improves in-depth, high resolution MS-based quantitative proteomics. We used U-[12C]-glucose as the metabolic precursor of all amino acids in yeast. This substantially increased the peptide monoisotopic ion intensity in bottom-up analyses, greatly improving identification scores and protein sequence coverage, and making it possible to address the dynamics of protein turnover at the proteome scale.