[Synthesis of iodoamino acids during in vitro thyroglobulin iodination in different states of its molecule].

Iodotyrosine and iodothyronine residues are formed in the protein molecule during bovine thyroglobulin iodination in vitro. Dissociation and reassociation of the thyroglobulin molecule have no significant influence on its iodoaminoacid composition. Thyroglobulin iodination in the presence of 8 M urea does not result in thyroxine synthesis despite the increased formation of iodotyrosine residues. Similarly, during iodination of reassociated thyroglobulin the new molecules of thyroxine are not formed either. It is presumed that during reassociation of thyroglobulin subunits the native conformation of the protein is not completely reconstituted. The results obtained suggest that the structure of thyroglobulin controls the distribution of the iodine atoms incorporated by the iodoaminoacid residues.