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Title: Characterization of thyroidal glutathione reductase

Glutathione levels were determined in bovine and rat thyroid tissue by enzymatic conjugation with 1-chloro-2,4-dinitrobenzene using glutathione S-transferase. Bovine thyroid tissue contained 1.31 {+-} 0.04 mM reduced glutathione (GSH) and 0.14 {+-} 0.02 mM oxidized glutathione (GSSG). In the rat, the concentration of GSH was 2.50 {+-} 0.05 mM while GSSG was 0.21 {+-} 0.03 mM. Glutathione reductase (GR) was purified from bovine thyroid to electrophoretic homogeneity by ion exchange, affinity and molecular exclusion chromatography. A molecular weight range of 102-109 kDa and subunit size of 55 kDa were determined for GR. Thyroidal GR was shown to be a favoprotein with one FAD per subunit. The Michaelis constants of bovine thyroidal GR were determined to be 21.8 {mu}M for NADPH and 58.8 {mu}M for GSSG. The effect of thyroid stimulating hormone (TSH) and thyroxine (T{sub 4}) on in vivo levels of GR and glucose 6-phosphate dehydrogenase were determined in rat thyroid homogenates. Both enzymes were stimulated by TSH treatment and markedly reduced following T{sub 4} treatment. Lysosomal hydrolysis of ({sup 125}I)-labeled and unlabeled thyroglobulin was examined using size exclusion HPLC.
Authors:
Publication Date:
OSTI Identifier:
6612843
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Fargo, ND (US); North Dakota State Univ. of Agriculture and Applied Science
Research Org:
North Dakota State Univ., Fargo, ND (USA)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; 59 BASIC BIOLOGICAL SCIENCES; CHLORINATED AROMATIC HYDROCARBONS; METABOLISM; GLUTATHIONE; BIOSYNTHESIS; OXIDOREDUCTASES; CHEMICAL COMPOSITION; CATTLE; CHROMATOGRAPHY; FRACTIONATION; IODINE 125; LIQUID COLUMN CHROMATOGRAPHY; MOLECULAR WEIGHT; NITRO COMPOUNDS; RATS; THYROID; THYROID HORMONES; TRACER TECHNIQUES; ANIMALS; AROMATICS; BETA DECAY RADIOISOTOPES; BODY; DAYS LIVING RADIOISOTOPES; DOMESTIC ANIMALS; DRUGS; ELECTRON CAPTURE RADIOISOTOPES; ENDOCRINE GLANDS; ENZYMES; GLANDS; HALOGENATED AROMATIC HYDROCARBONS; HORMONES; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; MAMMALS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC CHLORINE COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANS; PEPTIDE HORMONES; PEPTIDES; POLYPEPTIDES; PROTEINS; RADIOISOTOPES; RADIOPROTECTIVE SUBSTANCES; RODENTS; RUMINANTS; SEPARATION PROCESSES; SYNTHESIS; VERTEBRATES 560300* -- Chemicals Metabolism & Toxicology; 550201 -- Biochemistry-- Tracer Techniques