Abstract
Gp85 the major envelope glycoprotein of Rous sarcoma virus can be released from intact by virus treatment with 2-mercaptoethanol. Attempts were made to reassociate released gp85 to 2-mercaptoethanol treated virus. In order to study the biological activity and to analyse the reaction product with biochemical methods gp85 from a subgroup different from the recipient virus was used. Successfulin vitro phenotypic mixing could be shown. The biochemical analysis, however, revealed that no reassociation of gp85 and gp35 could be obtained. The biological activity was due to a strong association of whole gp85-gp35 molecules derived from the gp85 preparation to the recipient virus. These molecules were present as a minor contamination in the gp85 preparation.