Monoiodotyrosine formation during thyroglobulin processing in Golgi vesicles.
A golgi-enriched subfraction was obtained from porcine thyroid glands by differential centrifugation. When incubated in a suitable medium, these vesicles were able to concentrate iodide from the medium and bind it to protein. The iodination process was inhibited by methylmercapto-imidazole and was increased by the addition of an H2O2 generating system to the medium. Analysis of the protein content of the vesicles revealed the presence of 18 and 12-13 S thyroglobulin molecules, lacking mannose residues, and containing only monoiodotyrosine. It is concluded that in vitro, iodination can begin before exocytosis, in the smooth-surfaced vesicles derived from the golgi apparatus, as soon as N-acetylglucosamine is incorporated onto the pre-thyroglobulin molecule.
Bastiani
P
P
Institut de Chimie Biologique, C.N.R.S. U.A. 202, Université de Provence, Marseille, France.
Rognoni
J B
JB
D000818:Animals; D006056:Golgi Apparatus / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D007467:Iodoproteins / Q000378:metabolism; D007470:Monoiodotyrosine / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D013552:Swine; D013954:Thyroglobulin / Q000378:metabolism*; D013961:Thyroid Gland / Q000378:metabolism
D007467:Iodoproteins; D013954:Thyroglobulin; D006861:Hydrogen Peroxide; D007470:Monoiodotyrosine