CONDITIONS FOR THE FORMATION OF AN IODINATED AND TRITIATED PROTEIN COMBINATION DURING THE DEIODINATION OF DOUBLY LABELED I$sup 131$ AND H$sup 3$ THYROID HORMONES (in French)
Thyroid hormones doubly labeled in alpha - BETA position with H/sup 3/ and in 3',5' or 3' with I/sup 131/ (STAI/sup 131/,H/sup 3/!DL-thyroxine and (I/ sup 131/,H/sup 3/! 3,5,3'-triiodo-DL-thyronine) were deiodinated by mitochondria and several acellular preparations. The only labeled compounds produced under the experimental conditions adopted were I/sup 131/ and a protein complex, PX, which contained both H/sup 3/ and I/sup 131/. Since no H/sup 3/ loss occurred during the incubation, there was no exchange between the tritium atoms of the iodothyronine and the hydrogen atoms of the medium. The ratio of the specific activities of the two isotopes in the chromatographic zones where residual DLthyroxine or 3,5,3'-triiodo-DL-thyronine were located was identical to the blank after incubation with thyroxine deiodinase except where a disagreement was observed in the rate of deiodination calculated from the measurements of I/sup 131/and H/sup 3/. At the end of the reaction PX always contained a fraction of the I/sup 131/ and the total H/sup 3/ provided for by the iodothyronine that had disappeared. The I/sup 131/ concentration of PX is not constant during the incubation period. I/sup 131/ deiodination of PX took place in two steps, which seemed to indicate that the I/sup 131/ was presert in the protein in two different forms. All the preparations led to the same reaction products. (P.C.H.)
- Research Organization:
- College de France, Paris
- NSA Number:
- NSA-17-013927
- OSTI ID:
- 4750236
- Journal Information:
- Biochimica et Biophysica Acta (Netherlands), Journal Name: Biochimica et Biophysica Acta (Netherlands) Vol. Vol: 69; ISSN BBACA
- Country of Publication:
- Country unknown/Code not available
- Language:
- French
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