Identification and Isolation of Ovalbumin-synthesizing Polysomes

Polysomes involved in ovalbumin synthesis were identified by the binding of 1251-anti-ovalbumin to hen oviduct polysomes. Techniques were developed for the isolation of undegraded hen oviduct polysomes and for the preparation of 1251-y-globulin free of ribonuclease activity. The distribution of 1251-anti-ovalbumin in the polysome profile is in accordance with the size of the polysomes that are expected to be synthesizing ovalbumin. Anti-ovalbumin does not react with polysomes extracted from tissues that do not synthesize ovalbumin, and antibodies directed against a protein that is not synthesized in the oviduct do not bind to hen oviduct polysomes. These criteria indicate that the reaction is specific for polysomes that synthesize ovalbumin. Polysomes that bind 1251-anti-ovalbumin can be precipitated by the addition of ovalbumin and an excess of specific antibody.