A Study of the Action of Purified Thyroid Protease on l31I-Labelled Thyroglobulin

Abstract

The preparation of pig thyroglobulin labelled with 1311 is described and the results of the action of purified thyroid protease on different samples are presented. The major iodine-containing compounds liberated were found to be mono- and di-iodotyrosine, thyroxine, and tri-iodothyronine, together with a "peptide" fraction; of these mono-iodotyrosine, di-iodotyrosine, and the "peptide" predominated. Specific activities of these components were determined and compared with the values obtained following alkaline hydrolysis of the labelled protein.