Thyroglobulin: Proteins and Enzymes

Thyroglobulin is synthesized by the follicular epithelial cells of the thyroid. Thyroglobulin is the glycoprotein precursor to the thyroid hormones. Its synthesis and metabolism have seemingly wasteful features. It has a molecular weight of 660,000, with 2 identical subunits of MW 300,000 and 10% sugars; yet its complete hydrolysis yields only 2 to 4 molecules of the iodothyroxines T4 and T3. Baas et al. (1986) showed that the TG gene encodes an 8.7-kb mRNA, covers at least 300 kb of genomic ...