Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycolyl-CoA can be formed during the course of the beta-oxidation by rat liver mitochondria of 4-hydroxybutyrate. The existence of this beta-oxidation has been previously supported by the occurrence of 4-hydroxybutyrate and its beta-oxidation catabolites in urine from patients with 4-hydroxybutyric aciduria, an inborn error of gamma-aminobutyric acid metabolism due to the deficiency of succinic semialdehyde dehydrogenase. The characteristics of the mitochondrial beta-oxidation of 4-hydroxybutyrate were, in rat liver, compared with those of the mitochondrial beta-oxidation of butyrate. The inhibition by malonate of the oxidation of 4-hydroxybutyrate was about twofold weaker than that of oxidation of butyrate, whereas both oxidations were abolished by preincubating the mitochondria with 1 mM valproic acid, a known inhibitor of mitochondrial beta-oxidation. Mitochondria from rat kidney cortex were demonstrated to catalyse, as previously shown for hepatic mitochondria, the carnitine-dependent oxidation of 12-hydroxylauroyl-CoA-omega-Hydroxymonocarboxylyl-CoAs are thus concluded to be precursors of glycolyl-CoA also in rat kidney cortex. In addition, 3-hydroxypyruvate was found to be a precursor of glycolyl-CoA, since it was oxidized by bovine heart pyruvate dehydrogenase with a cofactor requirement similar to that of pyruvate oxidation. Glycolyl-CoA was a substrate of carnitine acetyltransferase (pigeon breast muscle). Pig heart citrate synthase was capable of catalyzing the condensation of glycolyl-CoA with oxaloacetate. The product of this reaction induced low NADH production rates dependent on the addition of porcine heart aconitase and isocitrate dehydrogenase.
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PMID:Studies on the metabolism of glycolyl-CoA. 197 13

The composition and properties of the tricarboxylic acid cycle of the microaerophilic human pathogen Helicobacter pylori were investigated in situ and in cell extracts using [1H]- and [13C]-NMR spectroscopy and spectrophotometry. NMR spectroscopy assays enabled highly specific measurements of some enzyme activities, previously not possible using spectrophotometry, in in situ studies with H. pylori, thus providing the first accurate picture of the complete tricarboxylic acid cycle of the bacterium. The presence, cellular location and kinetic parameters of citrate synthase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate oxidase, fumarate reductase, fumarase, malate dehydrogenase, and malate synthase activities in H. pylori are described. The absence of other enzyme activities of the cycle, including alpha-ketoglutarate dehydrogenase, succinyl-CoA synthetase, and succinate dehydrogenase also are shown. The H. pylori tricarboxylic acid cycle appears to be a noncyclic, branched pathway, characteristic of anaerobic metabolism, directed towards the production of succinate in the reductive dicarboxylic acid branch and alpha-ketoglutarate in the oxidative tricarboxylic acid branch. Both branches were metabolically linked by the presence of alpha-ketoglutarate oxidase activity. Under the growth conditions employed, H. pylori did not possess an operational glyoxylate bypass, owing to the absence of isocitrate lyase activity; nor a gamma-aminobutyrate shunt, owing to the absence of both gamma-aminobutyrate transaminase and succinic semialdehyde dehydrogenase activities. The catalytic and regulatory properties of the H. pylori tricarboxylic acid cycle enzymes are discussed by comparing their amino acid sequences with those of other, more extensively studied enzymes.
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PMID:The tricarboxylic acid cycle of Helicobacter pylori. 1009 6