Identification of a 27-kilodalton protein with the properties of type I iodothyronine 5'-deiodinase in human thyroid gland.
J Clin Endocrinol Metab
; 74(3): 533-8, 1992 Mar.
Article
en En
| MEDLINE
| ID: mdl-1740487
ABSTRACT
N-Bromoacetyl-[125I]T4(BrAc[125I]T4) was used as affinity label to identify type I 5'-deiodinase (5'-D) in human thyroid glands. Affinity labeled proteins were analyzed by autoradiography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Human thyroid microsomes labeled with BrAc[125I]T4 showed the most prominent radiolabeled band of protein at a mol wt of approximately 27,000 (p27). BrAc[125I]T4 incorporations into p27 were significantly higher in both Graves' and follicular adenomas than in normal thyroids. On the other hand, four cases out of five carcinomas were lower than the least value of normal thyroids. Furthermore, an excellent correlation was observed between 5'-D activities and quantities of p27 in all cases (r = 0.96; P less than 0.001). Labeling of p27 was strongly inhibited by preferred type I 5'-D substrate rT3, but to a lesser extent by poor substrate T4 or T3, and the type I 5'-D inhibitor, propylthiouracil and iopanoic acid, also inhibited the p27 labeling in normal and various diseases. In addition, the rate of enzyme inactivation by BrAcT4 equaled the rate of p27 labeling. These data suggest that p27 may be a type I 5'-D itself or at These data suggest that p27 may be a type I 5'-D itself or at least the substrate-binding subunit of this enzyme in human thyroid, and that both Graves' and follicular adenoma thyroids contain larger amounts of it, and papillary adenocarcinoma thyroids smaller than normal amounts.
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Banco de datos:
MEDLINE
Asunto principal:
Glándula Tiroides
/
Yoduro Peroxidasa
/
Isoenzimas
Tipo de estudio:
Diagnostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Clin Endocrinol Metab
Año:
1992
Tipo del documento:
Article
País de afiliación:
Japón