Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.¶
Why this mattered¶
Towbin, Staehelin, and Gordon’s 1979 paper mattered because it turned protein electrophoresis from a primarily visual separation technique into a platform for specific molecular identification. Before this work, polyacrylamide gels could resolve complex protein mixtures, but identifying a particular protein within that pattern was cumbersome and often indirect. The key shift was to move proteins out of the gel and immobilize them on nitrocellulose while preserving the electrophoretic pattern closely enough that antibodies, labeled secondary antibodies, enzymes, fluorophores, or other ligands could interrogate the separated proteins directly. In effect, the paper joined the resolving power of gel electrophoresis to the specificity of immunochemistry.
That combination made possible what soon became known as the Western blot. Its importance was not simply technical convenience, although the method was simpler and sensitive enough to detect very small amounts of protein. It changed the kinds of questions biologists could ask: whether a protein was present in a sample, whether it had the expected molecular weight, whether an antibody recognized one band or many, whether expression changed across tissues or conditions, and whether a purified factor corresponded to a protein seen in a complex extract. Because the protein remained immobilized and accessible, the same conceptual workflow could support radioactive, fluorescent, enzymatic, and later chemiluminescent detection systems.
The paper’s influence is visible across late twentieth-century molecular biology, cell biology, immunology, and medicine. Western blotting became a standard validation method for protein expression, antibody specificity, viral and autoimmune serology, signaling pathway activation, and recombinant protein production. It also helped anchor later proteomic thinking: proteins could be separated, transferred, probed, and interpreted as identifiable molecular species rather than anonymous gel bands. The paradigm shift was the creation of a durable bridge between physical separation and biological recognition, making specific protein detection a routine experimental language.
Abstract¶
A method has been devised for the electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets. The method results in quantitative transfer of ribosomal proteins from gels containing urea. For sodium dodecyl sulfate gels, the original band pattern was obtained with no loss of resolution, but the transfer was not quantitative. The method allows detection of proteins by autoradiography and is simpler than conventional procedures. The immobilized proteins were detectable by immunological procedures. All additional binding capacity on the nitrocellulose was blocked with excess protein; then a specific antibody was bound and, finally, a second antibody directed against the first antibody. The second antibody was either radioactively labeled or conjugated to fluorescein or to peroxidase. The specific protein was then detected by either autoradiography, under UV light, or by the peroxidase reaction product, respectively. In the latter case, as little as 100 pg of protein was clearly detectable. It is anticipated that the procedure will be applicable to analysis of a wide variety of proteins with specific reactions or ligands.
Related¶
- cite → Detection of specific sequences among DNA fragments separated by gel electrophoresis — Western blotting adapts Southern's gel-transfer and membrane-detection strategy from DNA fragments to proteins.
- cite → Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 — The protein-transfer method relies on SDS-polyacrylamide gel electrophoresis popularized in Laemmli's bacteriophage T4 protein-separation work.
- enables ← Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 — Laemmli's SDS-PAGE protein separation method created the gel-based protein bands that Towbin et al. transferred to nitrocellulose in Western blotting.