Related Experiment Video
Updated: Jul 5, 2026

Immunoprecipitation with an Anti-Epitope Tag Affinity Gel to Study Protein-Protein Interactions
Published on: January 5, 2024
Detection of protein-protein interactions by coprecipitation
1Harvard Medical School, Boston, Massachusetts.
Abstract:
Coprecipitation of proteins from whole-cell extracts is a valuable approach to test for physical interactions between proteins of interest. This unit describes basic approaches to immunoprecipitating tagged proteins from whole-cell extracts. The approaches described can be adapted for other systems. In a typical experiment, as described here, cells are lysed and a whole-cell extract is prepared under nondenaturing conditions. The protein is precipitated from the lysate with a solid-phase affinity matrix, and the precipitate is tested for the presence of a second specifically associated protein. The approach can be used for native or epitope-tagged proteins for which antibodies are available, or for recombinant proteins that have been engineered to bind with high affinity to a molecule that can be coupled to a solid-phase matrix.
Related Concept Videos
Immunoprecipitation
Chromatin Immunoprecipitation
Chromatin immunoprecipitation, also known as ChIP, is used to study protein-DNA or...
Protein Networks
These interactions can be represented through maps depicting protein-protein interaction networks, represented as nodes and edges. Nodes are circles that are representative of a protein,...
Protein-protein Interfaces
Precipitation and Co-precipitation

