Western blot

The western blot (sometimes called the protein immunoblot), or western blotting, is a widely used <a href="/facts/Analytical_technique/TfqLbFbz">analytical technique</a> in <a href="/facts/Molecular_biology/YgqU35ub">molecular biology</a> and <a href="/facts/Immunogenetics/SL5y7aP6">immunogenetics</a> to detect specific <a href="/facts/Proteins/Jxmagu3E">proteins</a> in a sample of tissue homogenate or extract. Besides detecting the proteins, this technique is also utilized to visualize, distinguish, and quantify the different proteins in a complicated protein combination.
Western blot technique uses three elements to achieve its task of separating a specific protein from a complex: separation by size, transfer of protein to a solid support, and marking target protein using a primary and secondary antibody to visualize. A <a href="/facts/Synthetic_antibody/DstktXsP">synthetic</a> or <a href="/facts/Polyclonal_antibodies/zerWqe2r">animal-derived</a> <a href="/facts/Antibody/MX8pdTdP">antibody</a> (known as the <a href="/facts/Primary_antibody/KB0tmpqE">primary antibody</a>) is created that recognizes and binds to a specific target protein. The <a href="/facts/Immunoelectrophoresis/b5nV9jF9">electrophoresis membrane</a> is washed in a solution containing the primary antibody, before excess antibody is washed off. A <a href="/facts/Secondary_antibody/KB0tmpqE">secondary antibody</a> is added which recognizes and binds to the primary antibody. The secondary antibody is visualized through various methods such as <a href="/facts/Staining/jqGqWEE1">staining</a>, <a href="/facts/Immunofluorescence/lBrwxaYI">immunofluorescence</a>, and radioactivity, allowing indirect detection of the specific target protein.
Other related techniques include <a href="/facts/Dot_blot/Kzaj9juv">dot blot</a> analysis, <a href="/facts/Quantitative_dot_blot/Kzaj9juv">quantitative dot blot</a>, <a href="/facts/Immunohistochemistry/knPpmAFf">immunohistochemistry</a> and <a href="/facts/Immunocytochemistry/vgfBrdUJ">immunocytochemistry</a>, where antibodies are used to detect proteins in tissues and cells by <a href="/facts/Immunostaining/hVg7s9nX">immunostaining</a>, and <a href="/facts/Enzyme-linked_immunosorbent_assay/8yvpYDtH">enzyme-linked immunosorbent assay</a> (ELISA).
The name western blot is a play on the <a href="/facts/Southern_blot/HXrr0Gz3">Southern blot</a>, a technique for <a href="/facts/DNA/nB89Iauz">DNA</a> detection named after its inventor, English biologist <a href="/facts/Edwin_Southern/U6Nj8GXr">Edwin Southern</a>. Similarly, detection of RNA is termed as <a href="/facts/Northern_blot/pRUrdy2n">northern blot</a>. The term western blot was given by W. Neal Burnette in 1981, although the method itself was independently invented in 1979 by Jaime Renart, Jakob Reiser, and <a href="/facts/George_Stark/D5eBxRyb">George Stark</a> at <a href="/facts/Stanford/JEQeF9z2">Stanford University</a>, and by Harry Towbin, Theophil Staehelin, and Julian Gordon at the <a href="/facts/Friedrich_Miescher_Institute_for_Biomedical_Research/zTQkruR0">Friedrich Miescher Institute</a> in <a href="/facts/Basel/EzXbzbUx">Basel</a>, <a href="/facts/Switzerland/LcGuxeTe">Switzerland</a>. The Towbin group also used secondary antibodies for detection, thus resembling the actual method that is almost universally used today. Between 1979 and 2019 "it has been mentioned in the titles, abstracts, and keywords of more than 400,000 <a href="/facts/PubMed/JlHAvMHt">PubMed</a>-listed publications" and may still be the most-used protein-analytical technique.

Western blot open-in-new

Western blot