Biosynthesis of gamma globulin: studies in a cell-free system.

Incorporation of C(14)-amino acids into high-molecular-weight material precipitable by trichloroacetic acid indicates that microsomal cell-free systems, derived from spleens of immunized rabbits, are active in protein synthesis. Protein was made soluble by ultrasonic irradiation of the cell-free incubation mixtures, and low-molecular-weight materials were removed by dialysis and gel filtration. Chromatography and radio-immunoelectrophoresis of this soluble protein fraction reveal C(14)-labeled protein having several characteristics of gamma globulin.