[Nature of the intracellular thyroid hormone receptor].

Thyroxine-binding proteins were isolated and purified by means of affine chromatography from the blood serum, 105 000 g of cytosol supernatant, non-histone protein fractions of chromatin, extracted with 0.4 M KCl. Identity of their molecular weights and of end aminoacids was found. A comparative study of proteins above, using chromatoelectrophoresis, has shown identity of their primary structure. The data obtained indicate, that chromatin and cytosol contain universal, thyroxine-binding protein, which structure is identical with that of prealbumin thyroxine-binding protein. This protein is considered to be a receptor, realizing the control of genome expression by thyroid hormones.