Presence of dityrosine bridges in thyroglobulin and their relationship with iodination.

The presence of dimeric thyroglobulin (19S), after reduction and alkylation, suggests that within thyroglobulin there may be intermolecular cross-links, other than disulphide bridges. However, the nature of these intermolecular cross-links is still unknown. In this study, we show the presence of 3-3' dityrosine bridges in the molecule of bovine thyroglobulin by NMR and fluorescence studies. Also, we evaluated the role of iodination in dityrosine formation in vivo and in vitro.