Which of the following techniques is NOT typically used for protein analysis?

The chosen answer is correct because Polymerase Chain Reaction (PCR) is a technique primarily used to amplify DNA, not to analyze proteins. PCR allows for the replication of a specific DNA sequence, making it easier to study genes and genetic variations. In contrast, the other techniques listed are directly involved with protein analysis.

Western blotting is a widely used technique for detecting specific proteins in a sample. It works by separating proteins based on size through gel electrophoresis, transferring them to a membrane, and then probing with specific antibodies to identify the target proteins.

Mass spectrometry is a powerful analytical tool that helps identify and quantify proteins by measuring the mass-to-charge ratio of their ions. This technique provides precise molecular weights and can also help in determining the structure of proteins, making it essential for protein analysis.

Enzyme-linked immunosorbent assay (ELISA) is another method used to quantify specific proteins. It uses antibodies and color change to detect the presence or concentration of proteins in a sample.

In summary, while techniques like Western blotting, mass spectrometry, and ELISA are integral to protein analysis, PCR serves a different purpose focused on DNA manipulation, confirming it as the correct answer to the question.