Affinity purification-mass spectrometry (AP-MS)

Affinity purification-mass spectrometry (AP-MS) is a technique used to identify and analyze the proteins that interact with a specific "bait" protein within cells. First, the bait protein is tagged and isolated using a specialized "capture" method that pulls it out of the cell mixture along with any connected proteins. These proteins are then purified and broken into smaller pieces. Mass spectrometry analyzes these pieces to determine their identities, revealing the network of proteins that associate with the bait. This helps researchers understand how proteins work together within biological systems.