Biosynthesis of the 32-kdalton uncoupling protein in brown adipose tissue of developing rabbits.

The biosynthesis of the 32-kdalton uncoupling protein of brown adipose tissue was examined with polysomes isolated from brown adipose tissue of developing rabbits. Polysomes were translated in a reticulocyte protein-synthesizing system and newly synthesized uncoupling protein was isolated with monospecific antibodies. The newly synthesized protein had the same molecular mass as the mature protein. Its synthesis is initiated and increases about five- to seven-fold before birth and decreases progressively after birth.