The entire complement of in vitro translation products derived from a mRNA population may be analyzed by polyacrylamide gel electrophoresis followed by fluorography and autoradiography. It is often necessary however to demonstrate the synthesis of a polypeptide translation product present in minimal amounts, or one comigrating with another product. In such cases, and also to prove the identity of particular translation products, it is possible to separate the particular polypeptide from the general population by specific immunoprecipitation with antisera raised specifically to the polypeptide of interest.
