Recombinant protein or a chemically synthesized bioactive fragment is immobilized on resin and used as a probe to capture interacting proteins directly from a cell extract.  Affinity-purified proteins are fractionated by gel electrophoresis and visualized by Coomassie staining.  Proteins that interact specifically are identified by comparing this gel profile to one obtained from cell lysates passed over a control resin lacking the immobilized probe protein.

Protocol: Affinity Purification of Interacting Proteins from Cell Lysates Protocol