Immunoprecipitation (IP) uses antigen-antibody reaction principle to isolate and concentrate a specific protein from a mixture of proteins. For example, such process can be used to pull out the protein of interest from a cell extract or culture supernatant via a protein A/G-coupled agarose beads. This technique can be done manually or by a high throughput automated magnetic bead platform, Precipitor™ developed by Abnova.
Types of Immunoprecipitation:
Individual protein Immunoprecipitation (IP):
A method to isolate the protein of interest from the mixture of proteins.
Protein complex Immunoprecipitation (Co-IP):
A method to analyze protein-protein interactions. Co-precipitated protein can then be identified by western blot analysis or by sequencing a purified protein band.
Chromatin Immunoprecipitation (ChIP):
A method to determine the location of DNA binding sites on the genome for the protein of interest. This technique gives a picture of the protein-DNA interactions that occur inside the nucleus of living cells or tissues.
RNA Immunoprecipitation (RIP):
Similar to chromatin immunoprecipitation (ChIP), but rather than targeting DNA binding proteins as in ChIP, RNA immunoprecipitation targets RNA binding proteins.