Immunoprecipitation is a method used to isolate a specific antigen from a mixture using the antigen-antibody interaction. It involves adding an antibody to a mixture containing the antigen and incubating to allow antigen-antibody complexes to form. These complexes are then incubated with immobilized secondary antibodies or protein A/G beads. Antigens isolated through immunoprecipitation can be analyzed by SDS-PAGE or Western blotting. It has various applications including isolating and detecting proteins of interest, studying protein-protein interactions, and identifying unknown proteins in complexes.

1. Dr. P. Saranraj
Head
Department of Microbiology
Sacred Heart College (Autonomous)
Tirupattur – 635 601
Tamil Nadu, India
Mobile: +91-9994146964; E.mail:
microsaranraj@gmail.com
IMMUNOPRECIPITATION

2. IMMUNOPRECIPITATION
 Immunoprecipitation (IP) is a method to isolate a
specific antigen from a mixture, using the Ag -
Ab interaction.
 Antigens isolated by IP are analyzed by SDS-
PAGE or Western blotting.
 In IP, an antibody is added first to a mixture
containing an antigen, and incubated overnight
at 4 °C under Shaking condition to allow Ag - Ab
complexes to form.
 Subsequently, the antigen-antibody complexes
are incubated overnight at 4 °C under Shaking
condition with an immobilized antibody against
the primary antibody (secondary antibody) or
with Protein A/G-coated beads to allow them to

4. Applications of Immunoprecipitation
 Isolate / Detect Proteins of interest
 Target gene identification.
 Enrichment of low abundant proteins.
 Study protein-protein interaction and protein
complexes.
 Identify unknown proteins in a protein complex
 Verify protein expression in a specific tissue.
 Determining Size/Molecular weight of protein.
 Determining Specific enzyme activity.