Mass spectrometry (MS) based proteomics has become an essential tool for biologists over the last decade. The ability of a mass spectrometer to identify thousands of proteins from a complex biological sample has revolutionized scientific experiments. To fully understand the function of the proteome in health and disease, however, one must have the ability to accurately quantify proteins in many different types of biological samples. The invention of faster and higher resolution mass spectrometers has enabled the quantification of complex proteome dynamics. Heavy stable isotopes are routinely employed to generate precise and accurate quantitative proteomic data. Peptides labeled with heavy stable isotopes share identical biochemical characteristics to “light” or unlabeled peptides except a difference in mass. Mixing heavy peptides with light peptides results in peptide pairs that co-elute into the mass spectrometer, which can easily distinguish between the peptides based on the mass difference. Quantifying differences between proteomes subjected to different biological conditions or experiments can be achieved when using the heavy peptides as an internal standard or a control. CIL offers a variety of stable isotope reagents for labeling any proteome for quantitative MS analysis. These stable isotope MS methods are bringing scientists closer to curing human diseases through quantitative biomarker analysis and quantitative proteomic analysis of animal models of disease.
Click here to download a technical note on Mass Spectrometry Signal Calibration for Protein Quantitation, written by Michael J. MacCoss, PhD, Associate Professor of Genome Sciences, University of Washington, School of Medicine.
Click here to download a technical note on Early Stable Isotope Labeling in Proteomics, written by Timothy D. Veenstra, PhD, NCI