Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Yeast aconitase [citrate (isocitrate) hydro-lyase, ED 4.2.1.3], inductively formed by Candida iipolytica in the presence of fluoroacetate, was purified approximately 100-fold by Sephadex G-100 gel filtration and DEAE-Sephadex column chromatography, yielding dark-brown needle crystals. The crystalline aconitase was homogenious as judged by polyacrylamide gel electrophoresis and sedimentation by ultracentrifugation. The enzyme showed maximal activity at pH 8.0 and at 55 degrees. It has an S20, W of 5.03 S, a molecular weight of 68,500 and an isolectric point of pH 4.2. The presence of 2.10 moles of iron per mole of the enzyme was demonstrated by atomic absorption spectroscopy.
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PMID:The aconitase of yeast. II. Crystallization and general properties of yeast aconitase. 23 89

Pig heart aconitase reacts with one mole of phenacyl bromide per molecule to give complete inactivation due to the alkylation of a cysteine reside at the active site. A tryptic peptide containing this essential residue has been isolated and its amino acid sequence determined at Ile-Gln-Leu-Leu-Cys *-Pro-Leu-Leu-Asn-Gln-Phe-Asp-Lys by manual methods and by the use of an automated solid phase sequencer. There is a limited similarity in amino acid sequence between this peptide and other peptides containing the cysteine residues involved in the binding of the iron-sulfur clusters of high-potential iron-sulfur protein of Rhodopseudomonas gelatinosa and rubredoxins from various bacteria.
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PMID:Amino acid sequence of a peptide containing an essential cysteine residue of pig heart aconitase. 721 10

Tricarballylate is the causative agent of grass tetany, a ruminant disease characterized by acute magnesium deficiency. Tricarballylate toxicity has been attributed to its ability to chelate magnesium and to inhibit aconitase, a Krebs cycle enzyme. Neither the ruminant nor the normal rumen flora can catabolize tricarballylate to ameliorate its toxic effects. However, the gram-negative enterobacterium Salmonella enterica can use tricarballylate as a carbon and energy source, providing an opportunity to study the genes and enzymes required for tricarballylate catabolism. The tricarballylate utilization (tcu) genes are organized into two transcriptional units, i.e., tcuR and tcuABC. Here, we report the initial biochemical analysis of TcuA. TcuA catalyzed the oxidation of tricarballylate to cis-aconitate. The apparent K(m) of TcuA for tricarballylate was 3.8 +/- 0.4 mM, with a V(max) of 7.9 +/- 0.3 mM min(-1), turnover number (k(cat)) of 6.7 x 10(-2) s(-1), and a catalytic efficiency (k(cat)/K(m)) of 17.8 M(-1) s(-1). Optimal activity was measured at pH 7.5 and 30 degrees C. The enzyme was inactivated at 45 degrees C. One mole of FAD was present per mole of TcuA. We propose a role for TcuB as an electron shuttle protein responsible for oxidizing FADH(2) back to FAD in TcuA.
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PMID:The FAD-dependent tricarballylate dehydrogenase (TcuA) enzyme of Salmonella enterica converts tricarballylate into cis-aconitate. 1685 37

Thermochemical processes developed for carbon capture and storage (CCS) offer high carbon capture capacities, but are generally hampered by low energy efficiency. Reversible cascade enzyme reactions are examined in this work for energy-efficient carbon sequestration. By integrating the reactions of two key enzymes of RTCA cycle, isocitrate dehydrogenase and aconitase, we demonstrate that intensified carbon capture can be realized through such cascade enzymatic reactions. Experiments show that enhanced thermodynamic driving force for carbon conversion can be attained via pH control under ambient conditions, and that the cascade reactions have the potential to capture 0.5 mol carbon at pH 6 for each mole of substrate applied. Overall it manifests that the carbon capture capacity of biocatalytic reactions, in addition to be energy efficient, can also be ultimately intensified to approach those realized with chemical absorbents such as MEA.
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PMID:Cascade enzymatic reactions for efficient carbon sequestration. 2570 41