DIFFERENTIAL STABILITY OF IODINE POOR AND IODINE RICH RAT THYROGLOBULIN

Publisher Website
Google Scholar
Abstract
In certain environments thyroglobulin is dissociated into 12S subunit or unfolded into 14–17S species. The unfolding and dissociating ability of various agents was examined on poorly iodinated (PIT) or iodine rich (IRT) rat thyroglobulins. According to the efficiency of provoking unfolding or dissociation these agents could be grouped in the following order: low ionic strength < chaotropic anions < chaotropic anions plus freezing and thawing < succinic anhydride and mild alkali < SDS < strong alkali. The degree of thyroglobulin changes was further dependent on the iodine concentration. No change of sedimentation pattern was obtained in the presence of 2-mercaptoethanol or after incomplete reduction and alkylation of the iodine rich protein. No stabilization of PIT was brought about by a number of oxidizing agents. Stabilization was only obtained by in vitro iodination. The main difference between the uneffected and unfolded or dissociated thyroglobulin species was in the amount of thyroxine, or, at lower levels of iodination, DIT. The results suggest that non-covalent, especially hydrophobic, rather than covalent interactions are involved in stabilization of conformation of the thyroglobulin molecule.

This publication has 0 references indexed in Scilit: