The X-ray crystallographic structure of medium-chain acyl-CoA dehydrogenase (MCAD)-octenoyl-CoA complex reveals that the 3'-phosphate group of CoA is confined to the exterior of the protein structure [approx. 15 A (1.5 nm) away from the enzyme active site], and is fully exposed to the outside solvent environment. To ascertain whether such a distal (3'-phosphate) fragment of CoA plays any signif...

Ignicoccus hospitalis is an anaerobic, autotrophic, hyperthermophilic Archaeum that serves as a host for the symbiotic/parasitic Archaeum Nanoarchaeum equitans. It uses a yet unsolved autotrophic CO(2) fixation pathway that starts from acetyl-CoA (CoA), which is reductively carboxylated to pyruvate. Pyruvate is converted to phosphoenol-pyruvate (PEP), from which glucogenesis as well as oxaloace...

The coenzyme A (CoA)-activated C5-dicarboxylic acids mesaconyl-CoA and beta-methylmalyl-CoA play roles in two as yet not completely resolved central carbon metabolic pathways in bacteria. First, these compounds are intermediates in the 3-hydroxypropionate cycle for autotrophic CO2 fixation in Chloroflexus aurantiacus, a phototrophic green nonsulfur bacterium. Second, mesaconyl-CoA and beta-meth...

The enzymes of fatty acid synthesis from liver and brain in normal and Blz-deprived rats were studied. Both total and specific activities of fatty acid synthetase and acetyl coenzyme A carboxylase were 2to 5-fold greater in Blz deprivation than in the normal state. The presence of excess activators in the BIp-deprived rat or an excess inhibitor in the normal rat was not found by serial admixtur...

Bacterial butyryl-CoA CoA-transferase activity plays a key role in butyrate formation in the human colon, but the enzyme and corresponding gene responsible for this activity have not previously been identified. A novel CoA-transferase gene is described from the colonic bacterium Roseburia sp. A2-183, with similarity to acetyl-CoA hydrolase as well as 4-hydroxybutyrate CoA-transferase sequences....

The metabolic fluxes of cis-5-enoyl-CoAs through the beta-oxidation cycle were studied in solubilized rat liver mitochondrial samples and compared with saturated acyl-CoAs of equal chain length. These studies were accomplished using either spectrophotometric assay of enzyme activities and/or the analysis of metabolites and precursors using a gas chromatographic method after conversion of CoA es...

The kinetics of carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) were examined in mitochondria from rat liver, heart and skeletal muscle as a function of pH over the range 6.8-7.6. In all three tissues raising the pH resulted in a fall in the Km for carnitine, no change in the Km for palmitoyl-CoA or Octanoyl-CoA, and a marked decrease in the inhibitory potency of malonyl-CoA. Studies with...

A simple and rapid mixed-phase method for the quantitative assay of 3-hydroxy-3-methylglutaryl (HMG)CoA reductase and a procedure for the efficient reactivation of Mg-ATP-inactivated microsomal HMG-CoA reductase by potato acid phosphatase are described. The mixed-phase assay entails the direct addition of the acidified, deproteinized incubation mixture to a toluene-based scintillation fluor. Th...

For improved production of coenzyme A (CoA), a mutant of Brevibacterium ammoniagenes IFO127071 resistant to oxypantetheine, the corresponding oxygen analog of pantetheine, was obtained. In the mutant, activity of pantothenate kinase (EC 2.7.1.33), the first-step enzyme for the biosynthesis of CoA from pantothenic acid, l-cysteine, and ATP, was about threefold higher than that in the parent stra...

BACKGROUND Malonyl-coenzyme A (CoA) is an important biosynthetic precursor in vivo. Although Escherichia coli is a useful organism for biosynthetic applications, its malonyl-CoA level is too low. RESULTS To identify strains with the best potential for enhanced malonyl-CoA production, we developed a whole-cell biosensor for rapidly reporting intracellular malonyl-CoA concentrations. The biosen...