The Properties of Thyroglobulin

Abstract

Abstract The extent of reduction of the disulfide groups in thyroglobulin by β-mercaptoethanol has been investigated as a function of pH in aqueous media and in 8 m urea. The products of reduction of thyroglobulin in dilute urea and in concentrated urea and guanidine solutions have been characterized by sedimentation and viscosity. Cleavage of a few disulfide bonds produces a smaller molecule of the same molecular weight as that obtained by quantitative reduction of all the bonds. On reduction in 5m guanidine, the 12 S subunit of thyroglobulin of ⅓ million molecular weight is cleaved into two equal or similar sized molecules.