sup 77 Se NMR studies on ovine erythrocyte glutathione peroxidase

Conference · Mon Mar 11 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5263788

Gettins, P; Crews, B C ^[1]

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1. Vanderbilt Univ., Nashville, TN (United States)

To facilitate {sup 77}Se NMR observation of the endogenous active site selenium in ovine erythrocyte glutathione peroxidase (GSHPx), lambs have been maintained on an artificial diet deficient in selenium and supplemented with 0.2 ppm 92atom% {sup 77}Se , as selenite. After 5 months, preparations of GSHPx showed that incorporation of selenium from the artificial diet represented 88% of the GSHPx selenium. Each monthly bleeding of two sheep routinely yielded 20mg of pure {sup 77}Se-enriched GSHPx. Limitations on the solubility of the enzyme have so far prevented observation of {sup 77}Se resonances from the intact enzyme. Upon denaturation, a broad resonance is observed at 277 ppm, indicating that the selenium is involved in mixed selenide sulfide bonds both inter and intramolecularly. Reduction of the SeS bonds with dithiothreitol resulted in an upfield shift of the {sup 77}Se resonance to {minus}212 ppm at pH 8 and {minus}55ppm at pH4.2, consistent with formation of Se- and SeH respectively. It is concluded that the selenium is most probably in the SeS or Se{sup {minus}} form in the intact enzyme. Relaxation time measurements were made at field strengths of 4.7 and 9.4T, which demonstrated the dominance of chemical shift anisotropy (CSA) relaxation for the selenium in GSHPx. A value of {le} 262 ppm was determined for the CSA of the iodoacetamide derivative of GSHPx.

• OSTI ID: 5263788
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:4
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHEMICAL SHIFT
DOMESTIC ANIMALS
ELEMENTS
ENZYMES
ERYTHROCYTES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAGNETIC RESONANCE
MAMMALS
MATERIALS
METABOLISM
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUTRITIONAL DEFICIENCY
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PEROXIDASES
PROTEINS
RADIOISOTOPES
RESONANCE
RUMINANTS
SECONDS LIVING RADIOISOTOPES
SELENIUM
SELENIUM 77
SELENIUM ISOTOPES
SEMIMETALS
SHEEP
STABLE ISOTOPES
TRACER TECHNIQUES
VERTEBRATES