@article {1212, title = {Characterization of malate dehydrogenase from the hyperthermophilic archaeon Pyrobaculum islandicum.}, journal = {Extremophiles}, volume = {11}, year = {2007}, month = {2007 Sep}, pages = {741-6}, abstract = {

Native and recombinant malate dehydrogenase (MDH) was characterized from the hyperthermophilic, facultatively autotrophic archaeon Pyrobaculum islandicum. The enzyme is a homotetramer with a subunit mass of 33 kDa. The activity kinetics of the native and recombinant proteins are the same. The apparent K ( m ) values of the recombinant protein for oxaloacetate (OAA) and NADH (at 80 degrees C and pH 8.0) were 15 and 86 microM, respectively, with specific activity as high as 470 U mg(-1). Activity decreased more than 90\% when NADPH was used. The catalytic efficiency of OAA reduction by P. islandicum MDH using NADH was significantly higher than that reported for any other archaeal MDH. Unlike other archaeal MDHs, specific activity of the P. islandicum MDH back-reaction also decreased more than 90\% when malate and NAD(+) were used as substrates and was not detected with NADP(+). A phylogenetic tree of 31 archaeal MDHs shows that they fall into 5 distinct groups separated largely along taxonomic lines suggesting minimal lateral mdh transfer between Archaea.

}, keywords = {Citric Acid Cycle, Hydrogen-Ion Concentration, Kinetics, Malate Dehydrogenase, Malates, Molecular Weight, NAD, NADP, Oxaloacetic Acid, Phylogeny, Protein Conformation, Protein Subunits, Pyrobaculum, Recombinant Proteins, Sequence Analysis, Protein, Substrate Specificity, Temperature}, issn = {1431-0651}, doi = {10.1007/s00792-007-0081-2}, author = {Yennaco, Lynda J and Hu, Yajing and Holden, James F} } @article {1214, title = {Characterization of dissimilatory Fe(III) versus NO3- reduction in the hyperthermophilic archaeon Pyrobaculum aerophilum.}, journal = {J Bacteriol}, volume = {188}, year = {2006}, month = {2006 Jan}, pages = {525-31}, abstract = {

The hyperthermophilic archaeon Pyrobaculum aerophilum used 20 mM Fe(III) citrate, 100 mM poorly crystalline Fe(III) oxide, and 10 mM KNO3 as terminal electron acceptors. The two forms of iron were reduced at different rates but with equal growth yields. The insoluble iron was reduced when segregated spatially by dialysis tubing, indicating that direct contact with the iron was not necessary for growth. When partitioned, there was no detectable Fe(III) or Fe(II) outside of the tubing after growth, suggesting that an electron shuttle, not a chelator, may be used as an extracellular mediator of iron reduction. The addition of 25 and 50\% (vol vol(-1)) cell-free spent insoluble iron media to fresh media led to growth without a lag phase. Liquid chromatography analysis of spent media showed that cultures grown in iron, especially insoluble iron, produced soluble extracellular compounds that were absent or less abundant in spent nitrate medium. NADH-dependent ferric reductase activity increased approximately 100-fold, while nitrate reductase activity decreased 10-fold in whole-cell extracts from iron-grown cells relative to those from nitrate-grown cells, suggesting that dissimilatory iron reduction was regulated. A novel 2,6-anthrahydroquinone disulfonate oxidase activity was more than 580-fold higher in iron-grown cells than in nitrate-grown cells. The activity was primarily (>95\%) associated with the membrane cellular fraction, but its physiological function is unknown. Nitrate-grown cultures produced two membrane-bound, c-type cytochromes that are predicted to be monoheme and part of nitrite reductase and a bc1 complex using genome analyses. Only one cytochrome was present in cells grown on Fe(III) citrate whose relative abundance was unchanged.

}, keywords = {Cytochromes c, Ferric Compounds, FMN Reductase, Hot Temperature, NAD, Nitrates, Oxidation-Reduction, Pyrobaculum}, issn = {0021-9193}, doi = {10.1128/JB.188.2.525-531.2006}, author = {Feinberg, Lawrence F and Holden, James F} } @article {391, title = {Identification of a novel dihydrolipoyl dehydrogenase-binding protein in the pyruvate dehydrogenase complex of the anaerobic parasitic nematode, Ascaris suum.}, journal = {J Biol Chem}, volume = {271}, year = {1996}, month = {1996 Mar 8}, pages = {5451-7}, abstract = {A novel dihydrolipoyl dehydrogenase-binding protein (E3BP) which lacks an amino-terminal lipoyl domain, p45, has been identified in the pyruvate dehydrogenase complex (PDC) of the adult parasitic nematode, Ascaris suum. Sequence at the amino terminus of p45 exhibited significant similarity with internal E3-binding domains of dihydrolipoyl transacetylase (E2) and E3BP. Dissociation and resolution of a pyruvate dehydrogenase-depleted adult A. suum PDC in guanidine hydrochloride resulted in two E3-depleted E2 core preparations which were either enriched or substantially depleted of p45. Following reconstitution, the p45-enriched E2 core exhibited enhanced E3 binding, whereas, the p45-depleted E2 core exhibited dramatically reduced E3 binding. Reconstitution of either the bovine kidney or A. suum PDCs with the A. suum E3 suggested that the ascarid E3 was more sensitive to NADH inhibition when bound to the bovine kidney core. The expression of p45 was developmentally regulated and p45 was most abundant in anaerobic muscle. In contrast, E3s isolated from anaerobic muscle or aerobic second-stage larvae were identical. These results suggest that during the transition to anaerobic metabolism, E3 remains unchanged, but it appears that a novel E3BP, p45, is expressed which may help to maintain the activity of the PDC in the face of the elevated intramitochondrial NADH/NAD+ ratios associated with anaerobiosis.}, keywords = {Amino Acid Sequence, Anaerobiosis, Animals, Ascaris suum, Binding Sites, Carrier Proteins, Dihydrolipoamide Dehydrogenase, Electrophoresis, Polyacrylamide Gel, Flavin-Adenine Dinucleotide, Helminth Proteins, Kinetics, Larva, Molecular Sequence Data, NAD, Oxidation-Reduction, Pyruvate Dehydrogenase Complex, Sequence Homology, Amino Acid}, issn = {0021-9258}, author = {Klingbeil, M M and Walker, D J and Arnette, R and Sidawy, E and Hayton, K and Komuniecki, P R and Komuniecki, R} } @article {1739, title = {Bacterial metabolism of resorcinylic compounds: purification and properties of orcinol hydroxylase and resorcinol hydroxylase from Pseudomonas putida ORC.}, journal = {Eur J Biochem}, volume = {61}, year = {1976}, month = {1976 Jan 2}, pages = {259-69}, abstract = {

The hydroxylase activities observed in extracts of Pseudomonas putida ORC after growth on orcinol and resorcinol as sole source of carbon have been purified to homogeneity. Both enzymes were shown to be flavoproteins and to contain approximately 1 mol of FAD for each polypeptide chain, S20,W values for each enzyme are 4.1 +/- 0.1 and are independent of the presence of their aromatic substrates. Molecular weight determinations under native (approximately 68000) and denaturing (approximately 70000) conditions indicated that they are monomeric. The visible absorption spectra identical but the circular dichroic spectra of the two proteins can be distinguished. Although each protein catalyzes the NAD(P)H and O2-dependent hydroxylation of both orcinol and resorcinol, the efficiency of the transformations of the substrates by the two enzymes is radically different; furthermore resorcinol hydroxylase is much more versatile in the aromatic compounds it can utilize as substrates and effectors. Other properties of the enzymes which clearly establish their own identity include their serological characteristics and amino acid composition; the latter property is particularly evident when the quantities of valine and alanine residues are compared. The synthesis of each enzyme is also under different regulatory constraints, being controlled by the substrate used for growth.

}, keywords = {Amino Acids, Circular Dichroism, Flavin-Adenine Dinucleotide, Mixed Function Oxygenases, Molecular Weight, NAD, NADP, Oxidation-Reduction, Protein Conformation, Pseudomonas, Resorcinols, Spectrophotometry, Spectrophotometry, Ultraviolet}, issn = {0014-2956}, author = {Ohta, Y and Ribbons, D W} } @article {1707, title = {Citrate synthase.}, journal = {Curr Top Cell Regul}, volume = {10}, year = {1976}, month = {1976}, pages = {161-204}, keywords = {Adenosine Diphosphate, Adenosine Monophosphate, Adenosine Triphosphate, Amino Acids, Animals, Bacteria, Binding Sites, Cations, Divalent, Cations, Monovalent, Citrate (si)-Synthase, Dithionitrobenzoic Acid, Ketoglutaric Acids, Kinetics, Molecular Weight, NAD, NADP, Oxo-Acid-Lyases, Protein Binding, Species Specificity}, issn = {0070-2137}, author = {Weitzman, P D and Danson, M J} } @article {1710, title = {Delineation of the intimate details of the backbone conformation of pyridine nucleotide coenzymes in aqueous solution.}, journal = {Biochem Biophys Res Commun}, volume = {66}, year = {1975}, month = {1975 Oct 27}, pages = {1173-9}, keywords = {Fourier Analysis, Magnetic Resonance Spectroscopy, Models, Molecular, Molecular Conformation, NAD, NADP, Structure-Activity Relationship, Temperature}, issn = {0006-291X}, author = {Bose, K S and Sarma, R H} } @article {1727, title = {Inhibition of aldehyde reductase isoenzymes in human and rat brain.}, journal = {Biochem Pharmacol}, volume = {24}, year = {1975}, month = {1975 Oct 15}, pages = {1865-9}, keywords = {Aldehyde Oxidoreductases, Animals, Anticonvulsants, Barbiturates, Brain, Glutethimide, Humans, Hydantoins, In Vitro Techniques, Isoenzymes, Kinetics, NAD, NADP, Rats, Succinimides}, issn = {0006-2952}, author = {Ris, M M and Deitrich, R A and Von Wartburg, J P} }