Affinity purification mass spectrometry
- Affinity purification mass spectrometry
- Affinity purification is the capture of biological material via specific enrichment with a ligand coupled to a solid support. Many types of ligands can be used in affinity purification, including DNA and RNA molecules (most often oligonucleotides), chemicals, lipids, peptides, or proteins, with some of the most widely used ligands for affinity purification being antibodies. In AP-MS, a single protein or molecule of interest is affinity captured in a matrix as bait. A protein mixture (often a lysate from the cell or tissue of interest) is passed through the matrix, and interacting partners (prey) are retained by interaction with the bait. Proteins that do not interact pass through the matrix and are discarded. There are multiple variations in the affinity purification step, including immunoprecipitation and pull-down of epitope tagged molecules. Once purified, proteins can be processed for direct analysis by MS or, fractionated to reduce sample complexity.