Photoaffinity labelling of the rat liver nuclear thyroid hormone receptor with (/sup 125/I)triiodothyronine

Journal Article · Mon Nov 01 04:00:00 EST 1982 · Endocrinology; (United States)

OSTI ID:6440106

David-Inouye, Y ^[1]; Somack, R; Nordeen, S K; Apriletti, J W; Baxter, J D; Eberhardt, N L

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1. Univ. of California, San Francisco

(/sup 125/I)Triiodothyronine (T/sub 3/) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that (/sup 125/I)T/sub 3/ covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 +/- 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T/sub 3/ and thyroxine (T/sub 4/) similar to those that inhibit binding of (/sup 125/I)T/sub 3/ by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabelled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that (/sup 125/I)T/sub 3/ can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 +/- 0.5 pH units.

• OSTI ID: 6440106
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 111:5; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
550201 -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BODY
CHEMICAL REACTIONS
CHEMISTRY
COVALENCE
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
GLANDS
HORMONES
INHIBITION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LIVER
MAMMALS
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PEPTIDES
PH VALUE
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLYPEPTIDES
PROTEINS
RADIOCHEMISTRY
RADIOISOTOPES
RADIORECEPTOR ASSAY
RATS
RECEPTORS
RODENTS
THYROID HORMONES
TRACER TECHNIQUES
TRIIODOTHYRONINE
VERTEBRATES