Protein Turnover
Heavy water metabolic labeling followed by liquid chromatography coupled with mass spectrometry is a powerful tool for high-throughput studies of the turnover of individual proteins in vivo. D2O enriched drinking water labels all non-essential
amino acids and results in the labeling all peptides. The turnover rate is determined from exponential decay modeling of the depletion of the monoisotopic relative isotope abundance. The turnover rate of thousands of proteins from different tissues
can been estimated using this technique. Relative abundances of mass isotopomers shifted during the gradual incorporation of deuterium from heavy water. Shown below are the isotope profiles of peptide, NLDKEYLPIGGLAEFCK, at three labeling durations:
0, 3, and 21 days. The turnover rate is determined from the depletion of the monoisotopic RIA, I0(t). See PMID: 37069333 for more details.
Other methods, such as SILAC labelling for cell lines, can also be analyzed by the MSF.