Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

NADH dehydrogenase is an iron-sulfur flavoprotein which is isolated and purified from Complex I (mitochondrial NADH: ubiquinone oxidoreductase) by resolution with NaClO4. The activity of the enzyme (followed as NADH: 2-methylnaphthoquinone oxidoreductase) increases linearly with protein concentration (in the range between 0.2 and 1.0 mg/ml) and decreases with aging upon incubation on ice. In the present work a good correlation was found between enzymic activity and labile sulfide content, at least within the limits of sensitivity of the assays employed. Rhodanese (thiosulfate: cyanide sulfurtransferase (EC 2.8.1.1) purified from bovine liver mitochondria was shown to restore, in the presence of thiosulfate, the activity of the partly inactivated NADH dehydrogenase. Concomitantly, sulfur was transferred from thiosulfate to the flavoprotein and incorporated as acid-labile sulfide. Rhodanese-mediated sulfide transfer was directly demonstrated when the reactivation of NADH dehydrogenase was performed in the presence of radioactive thiosulfate (labeled in the outer sulfur) and the 35S-loaded flavoprotein was re-isolated by gel filtration chromatography. The results indicated that the [35S]sulfide was inserted in NADH dehydrogenase and appeared to constitute the structural basis for the increase in enzymic activity.
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PMID:Interaction of rhodanese with mitochondrial NADH dehydrogenase. 640 20

The inorganic sulfane tetrathionate (-O3SSSSO3-) resembles glutathione trisulfide (GSSSG) in that it remarkably activates the reduction of cytochrome c by GSH, both under aerobic and anaerobic conditions. These observations can be explained by the formation of the persulfide GSS-, due to nucleophilic displacements of sulfane sulfur. The GSS- species has previously been proposed to act as a chain carrier in the catalytic reduction of cytochrome c, and perthiyl radicals GSS., formed in the reduction step, were thought to recycle to sulfane via dimerization to GSSSSG.2 The present study provides some arguments in favour of a chain mechanism involving the GSS. + GS-<-->(GSSSG).- equilibrium and sulfane regeneration by a second electron transfer from (GSSSG).- to cytochrome c. Thiosulfate sulfurtransferase (rhodanese) is shown to act as a cytochrome c reductase in the presence of thiosulfate and GSH, and again the generation of GSS- can be envisaged to explain this result.
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PMID:Sulfane-activated reduction of cytochrome c by glutathione. 839 9