Quantitative Proteomics: Techniques and Applications

This lecture discusses the principles and methodologies of quantitative proteomics, emphasizing the importance of quantitation in biological systems. The instructor begins by highlighting the necessity of measuring biological phenomena quantitatively, referencing Galileo's assertion that science must be quantitative. Different types of quantitation are introduced, including relative quantitation, which measures ratios between samples, and absolute quantitation, which provides physical units like moles or concentrations. The lecture explains how signal intensity from mass spectrometry is utilized to derive protein quantities. Various labeling strategies for quantitative proteomics are also covered, including metabolic labeling using isotopes and chemical labeling methods. The instructor details how these techniques allow for the comparison of samples by analyzing peptides that are chemically identical but distinguishable by mass. This approach enables researchers to obtain relative quantitation by calculating ratios of peptide intensities from different samples, thus facilitating a deeper understanding of protein abundance in biological contexts.