Correlation of the effects of citric acid cycle metabolites on succinate oxidation by rat liver mitochondria and submitochondrial particles.
1. Succinate dehydrogenase is inhibited by citrate and beta-hydroxy-butyrate in a complex manner, both in mitochondria and submitochondrial particles. Kinetics of inhibition in the particles points to a competitive component in the mechanism involved. 2. Pyruvate, alpha-ketoglutarate, malate, and glutamate stimulate oxidation of succinate by mitochondria. 3. Stimulation by alpha-ketoglutarate and glutamate is not influenced by the presence of rotenone. 4. Stimulation by pyruvate is higher in the absence of rotenone and increases significantly in the presence of K+ and valinomycin. Pyruvate supplies in mitochondria reducing equivalents for malate dehydrogenase operating in the reverse direction-reduction of oxaloacetate to malate. 5. Stimulation by malate is higher in the presence of rotenone.
D000818:Animals; D002951:Citrates / Q000494:pharmacology; D002952:Citric Acid Cycle; D005971:Glutamates / Q000494:pharmacology; D006885:Hydroxybutyrates / Q000494:pharmacology; D066298:In Vitro Techniques; D007656:Ketoglutaric Acids / Q000494:pharmacology; D007700:Kinetics; D008293:Malates / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D010710:Phosphates / Q000494:pharmacology; D011773:Pyruvates / Q000494:pharmacology; D051381:Rats; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D013386:Succinates / Q000494:pharmacology
D002951:Citrates; D005971:Glutamates; D006885:Hydroxybutyrates; D007656:Ketoglutaric Acids; D008293:Malates; D010710:Phosphates; D011773:Pyruvates; D013386:Succinates; D013385:Succinate Dehydrogenase