Final answer:
The Western blot is a procedure used to detect specific proteins in a sample by transferring them from a PAGE gel to a nitrocellulose membrane and probing with antibodies.
Step-by-step explanation:
The procedure you're asking about is known as the Western blot. It is a laboratory method used for the detection of specific proteins in a sample. After proteins are separated using polyacrylamide gel electrophoresis (PAGE), they are transferred to a nitrocellulose filter or membrane.
This process uses an electric current to facilitate the transfer. The proteins on the membrane are then probed with primary antibodies that bind specifically to the target protein. To visualize the proteins, secondary antibodies that are linked to a molecular beacon, such as an enzyme or fluorophore, are applied. If enzyme-linked antibodies are used, a chromogenic substrate is added, which reacts and develops color in the presence of the enzyme, indicating the location of the protein.
Additionally, immunoblot assays like the Western blot can also be used for identifying different antibody classes in plasma or serum, as well as the presence of specific antigens. This technique is critical in fields such as diagnosis of diseases like AIDS, where proteins from the HIV virus can be detected in an individual's serum using this method.