[Properties of rat liver polyribosomes synthesizing transferrin]

A radioimmunological study of rat liver polyribosomes synthesizing transferrin was carried out. The 125I-labelled monospecific antibodies against transferrin interact with membrane-bound liver polyribosomes to form a specific antigen-antibody complex. No binding of 125I-antibodies against transferrin to free liver polyribosomes was observed. The transferrin polyribosomes contain 11-13 monoribosomes per 1 molecule of mRNA. An injection of cycloheximide to the animals results in an increase in the size of the transferrin polyribosomes up to 16 monoribosomes per 1 mRNA molecule. During translation of the liver polyribosomal fractions in a cell-free system of wheat embryos only the membrane-bound polyribosomes were capable to synthesize immunoprecipitated transferrin.