Synthesis in vitro of rat brown adipose tissue 32 000 Mr protein

The synthesis of the mitochondrial inner membrane 32 000 Mr protein from rat brown adipose tissue was examined. Polysomes from the tissue were translated in a reticulocyte lysate protein-synthesizing system and newly-synthesized protein isolated with a monospecific antibody against the 32 000 Mr protein. The newly-synthesized protein had the same relative molecular mass as the mature protein. It was taken up by mitochondria isolated from Chinese hamster ovary cells into a form resistant to trypsin.