[Cellular contaminants and structural proteins of Rous sarcoma virus (RSV), studied by polyacrylamide gel electrophoresis].

The number of polypeptides in highly purified preparations of RSV, of two different subgroups, produced in culture, has been compared to the polypeptides present in the supernatant of uninfected cultures and processed in identical manner. The analysis of PAGE-SDS shows that from 13 to 18 polypeptides present in viral preparations may be cellular contaminants. Fewer contaminating polypeptides are found in the myeloblastosis virus purified from plasma of Chicken.