Apoenzymes: The protein components of enzyme complexes (HOLOENZYMES). An apoenzyme is the holoenzyme minus any cofactors (ENZYME COFACTORS) or prosthetic groups required for the enzymatic function.Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).Pyridoxal Phosphate: This is the active form of VITAMIN B 6 serving as a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate (PYRIDOXAMINE).Methylmalonyl-CoA Mutase: An enzyme that catalyzes the conversion of methylmalonyl-CoA to succinyl-CoA by transfer of the carbonyl group. It requires a cobamide coenzyme. A block in this enzymatic conversion leads to the metabolic disease, methylmalonic aciduria. EC 5.4.99.2.Flavin-Adenine Dinucleotide: A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)Pyridoxal: The 4-carboxyaldehyde form of VITAMIN B 6 which is converted to PYRIDOXAL PHOSPHATE which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid.D-Amino-Acid OxidaseKinetics: The rate dynamics in chemical or physical systems.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Pyridoxamine: The 4-aminomethyl form of VITAMIN B 6. During transamination of amino acids, PYRIDOXAL PHOSPHATE is transiently converted into pyridoxamine phosphate.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Coenzymes: Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.Aspartate Aminotransferases: Enzymes of the transferase class that catalyze the conversion of L-aspartate and 2-ketoglutarate to oxaloacetate and L-glutamate. EC 2.6.1.1.Dihydrolipoamide Dehydrogenase: A flavoprotein containing oxidoreductase that catalyzes the reduction of lipoamide by NADH to yield dihydrolipoamide and NAD+. The enzyme is a component of several MULTIENZYME COMPLEXES.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.PQQ Cofactor: A pyrrolo-quinoline having two adjacent keto-groups at the 4 and 5 positions and three acidic carboxyl groups. It is a coenzyme of some DEHYDROGENASES.Tryptophanase: An enzyme that catalyzes the conversion of L-tryptophan and water to indole, pyruvate, and ammonia. It is a pyridoxal-phosphate protein, requiring K+. It also catalyzes 2,3-elimination and beta-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. (From Enzyme Nomenclature, 1992) EC 4.1.99.1.CobamidesPropanediol Dehydratase: An enzyme that catalyzes the dehydration of 1,2-propanediol to propionaldehyde. EC 4.2.1.28.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Tyrosine Decarboxylase: A pyridoxal-phosphate protein that catalyzes the conversion of L-tyrosine to tyramine and carbon dioxide. The bacterial enzyme also acts on 3-hydroxytyrosine and, more slowly, on 3-hydroxyphenylalanine. (From Enzyme Nomenclature, 1992) EC 4.1.1.25.Transketolase: An enzyme of the transferase class that catalyzes the conversion of sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate to D-ribose 5-phosphate and D-xylulose 5-phosphate in the PENTOSE PHOSPHATE PATHWAY. (Dorland, 27th ed) EC 2.2.1.1.Glycine Hydroxymethyltransferase: A pyridoxal phosphate enzyme that catalyzes the reaction of glycine and 5,10-methylene-tetrahydrofolate to form serine. It also catalyzes the reaction of glycine with acetaldehyde to form L-threonine. EC 2.1.2.1.Pyruvate OxidaseCatalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Thiamine Pyrophosphate: The coenzyme form of Vitamin B1 present in many animal tissues. It is a required intermediate in the PYRUVATE DEHYDROGENASE COMPLEX and the KETOGLUTARATE DEHYDROGENASE COMPLEX.Cobalt: A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.Pyruvate Decarboxylase: Catalyzes the decarboxylation of an alpha keto acid to an aldehyde and carbon dioxide. Thiamine pyrophosphate is an essential cofactor. In lower organisms, which ferment glucose to ethanol and carbon dioxide, the enzyme irreversibly decarboxylates pyruvate to acetaldehyde. EC 4.1.1.1.Dithionitrobenzoic Acid: A standard reagent for the determination of reactive sulfhydryl groups by absorbance measurements. It is used primarily for the determination of sulfhydryl and disulfide groups in proteins. The color produced is due to the formation of a thio anion, 3-carboxyl-4-nitrothiophenolate.Ethanolamine Ammonia-Lyase: An enzyme that catalyzes the deamination of ethanolamine to acetaldehyde. EC 4.3.1.7.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Lyases: A class of enzymes that catalyze the cleavage of C-C, C-O, and C-N, and other bonds by other means than by hydrolysis or oxidation. (Enzyme Nomenclature, 1992) EC 4.Glucose Dehydrogenases: D-Glucose:1-oxidoreductases. Catalyzes the oxidation of D-glucose to D-glucono-gamma-lactone and reduced acceptor. Any acceptor except molecular oxygen is permitted. Includes EC 1.1.1.47; EC 1.1.1.118; EC 1.1.1.119 and EC 1.1.99.10.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Tryptophan Oxygenase: A dioxygenase with specificity for the oxidation of the indoleamine ring of TRYPTOPHAN. It is a LIVER-specific enzyme that is the first and rate limiting enzyme in the kynurenine pathway of TRYPTOPHAN catabolism.L-Serine Dehydratase: A PYRIDOXAL-phosphate containing enzyme that catalyzes the dehydration and deamination of L-serine to form pyruvate. This enzyme was formerly listed as EC 4.2.1.13.NAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)Ornithine-Oxo-Acid Transaminase: A pyridoxal phosphate enzyme that catalyzes the formation of glutamate gamma-semialdehyde and an L-amino acid from L-ornithine and a 2-keto-acid. EC 2.6.1.13.Glucose 1-Dehydrogenase: A glucose dehydrogenase that catalyzes the oxidation of beta-D-glucose to form D-glucono-1,5-lactone, using NAD as well as NADP as a coenzyme.Glucose Oxidase: An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC 1.1.3.4.Holoenzymes: Catalytically active enzymes that are formed by the combination of an apoenzyme (APOENZYMES) and its appropriate cofactors and prosthetic groups.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Sulfhydryl Compounds: Compounds containing the -SH radical.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.Hydro-Lyases: Enzymes that catalyze the breakage of a carbon-oxygen bond leading to unsaturated products via the removal of water. EC 4.2.1.Pyridoxine: The 4-methanol form of VITAMIN B 6 which is converted to PYRIDOXAL PHOSPHATE which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. Although pyridoxine and Vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990).Flavins: Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.Isomerases: A class of enzymes that catalyze geometric or structural changes within a molecule to form a single product. The reactions do not involve a net change in the concentrations of compounds other than the substrate and the product.(from Dorland, 28th ed) EC 5.Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Urease: An enzyme that catalyzes the conversion of urea and water to carbon dioxide and ammonia. EC 3.5.1.5.Molecular Weight: The sum of the weight of all the atoms in a molecule.Flavin Mononucleotide: A coenzyme for a number of oxidative enzymes including NADH DEHYDROGENASE. It is the principal form in which RIBOFLAVIN is found in cells and tissues.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Bromides: Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Cations, Divalent: Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Glyceraldehyde-3-Phosphate Dehydrogenases: Enzymes that catalyze the dehydrogenation of GLYCERALDEHYDE 3-PHOSPHATE. Several types of glyceraldehyde-3-phosphate-dehydrogenase exist including phosphorylating and non-phosphorylating varieties and ones that transfer hydrogen to NADP and ones that transfer hydrogen to NAD.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.Guanidines: A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.Dialysis: A process of selective diffusion through a membrane. It is usually used to separate low-molecular-weight solutes which diffuse through the membrane from the colloidal and high-molecular-weight solutes which do not. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Methylmalonic Acid: A malonic acid derivative which is a vital intermediate in the metabolism of fat and protein. Abnormalities in methylmalonic acid metabolism lead to methylmalonic aciduria. This metabolic disease is attributed to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.

Comparison of the backbone dynamics of the apo- and holo-carboxy-terminal domain of the biotin carboxyl carrier subunit of Escherichia coli acetyl-CoA carboxylase. (1/550)

The biotin carboxyl carrier protein (BCCP) is a subunit of acetyl-CoA carboxylase, a biotin-dependent enzyme that catalyzes the first committed step of fatty acid biosynthesis. In its functional cycle, this protein engages in heterologous protein-protein interactions with three distinct partners, depending on its state of post-translational modification. Apo-BCCP interacts specifically with the biotin holoenzyme synthetase, BirA, which results in the post-translational attachment of biotin to a single lysine residue on BCCP. Holo-BCCP then interacts with the biotin carboxylase subunit of acetyl-CoA carboxylase, which leads to the addition of the carboxylate group of bicarbonate to biotin. Finally, the carboxy-biotinylated form of BCCP interacts with transcarboxylase in the transfer of the carboxylate to acetyl-CoA to form malonyl-CoA. The determinants of protein-protein interaction specificity in this system are unknown. The NMR solution structure of the unbiotinylated form of an 87 residue C-terminal domain fragment (residue 70-156) of BCCP (holoBCCP87) and the crystal structure of the biotinylated form of a C-terminal fragment (residue 77-156) of BCCP from Escherichia coli acetyl-CoA carboxylase have previously been determined. Comparative analysis of these structures provided evidence for small, localized conformational changes in the biotin-binding region upon biotinylation of the protein. These structural changes may be important for regulating specific protein-protein interactions. Since the dynamic properties of proteins are correlated with local structural environments, we have determined the relaxation parameters of the backbone 15N nuclear spins of holoBCCP87, and compared these with the data obtained for the apo protein. The results indicate that upon biotinylation, the inherent mobility of the biotin-binding region and the protruding thumb, with which the biotin group interacts in the holo protein, are significantly reduced.  (+info)

Dietary thiamin level influences levels of its diphosphate form and thiamin-dependent enzymic activities of rat liver. (2/550)

This study was prompted by our incomplete understanding of the mechanism responsible for the clinical benefits of pharmacological doses of thiamin in some patients with maple syrup urine disease (MSUD) and the question of whether thiamin diphosphate (TDP), a potent inhibitor of the activity of the protein kinase that phosphorylates and inactivates the isolated branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex, affects the activity state of the complex. Rats were fed a chemically-defined diet containing graded levels of thiamin (0, 0.275, 0.55, 5.5, and 55 mg thiamin/kg diet). Maximal weight gain was attained over a 3-wk period only in rats fed diets with 5.5 and 55 mg thiamin/kg. Feeding rats the thiamin-free diet for just 2 d caused loss of nearly half of the TDP from liver mitochondria. Three more days caused over 70% loss, an additional 3 wk, over 90%. Starvation for 2 d had no effect, suggesting a mechanism for conservation of TDP in this nutritional state. Mitochondrial TDP was higher in rats fed pharmacological amounts of thiamin (55 mg thiamin/kg diet) than in rats fed adequate thiamin for maximal growth. Varying dietary thiamin had marked but opposite effects on the activities of alpha-ketoglutarate dehydrogenase (alpha-KGDH) and BCKDH. Thiamin deficiency decreased alpha-KGDH activity, increased BCKDH activity, and increased the proportion of BCKDH in the active, dephosphorylated, state. Excess dietary thiamin had the opposite effects. TDP appears to be more tightly associated with alpha-KGDH than BCKDH in thiamin-deficient rats, perhaps denoting retention of alpha-KGDH activity at the expense of BCKDH activity. Thus, thiamin deficiency and excess cause large changes in mitochondrial TDP levels that have a major influence on the activities of the keto acid dehydrogenase complexes.  (+info)

Structural characterization of l-aspartate oxidase and identification of an interdomain loop by limited proteolysis. (3/550)

l-Aspartate oxidase is the first enzyme in the de novo biosynthesis of pyridinic coenzymes in facultative aerobic organisms. The enzyme is FAD dependent and it shares common features with both the oxidase and the fumarate reductase classes of flavoproteins. In this report we focused our attention on the supersecondary structure of the molecule by means of limited proteolysis studies. Moreover the polymerization state of the protein at different pH and the interactions with NAD and its analogues are described. The results suggest that l-aspartate oxidase is a monomer at pH values lower than 4.5 and a dimer at pH values higher than 6.5. The protein is organized in two major domains connected by a flexible loop located in the 120-140 region. The data obtained by limited proteolysis of the holo and the apo form in the presence and in the absence of substrates (fumarate and menadione), inhibitors (succinate) and NAD allows the proposition that both domains are involved in the binding of the flavin coenzyme. Moreover the data reported in this manuscript suggest that NAD inhibits l-aspartate oxidase activity by competing with the flavin for the binding to the enzyme.  (+info)

Effects of divalent metal ions on the activity and conformation of native and 3-fluorotyrosine-PvuII endonucleases. (4/550)

The activities of restriction enzymes are important examples of Mg(II)-dependent hydrolysis of DNA. While a number of crystallographic studies of enzyme-DNA complexes have also involved metal ions, there have been no solution studies exploring the relationship between enzyme conformation and metal-ion binding in restriction enzymes. Using PvuII restriction endonuclease as a model system, we have successfully developed biosynthetic fluorination and NMR spectroscopy as a solution probe of restriction-enzyme conformation. The utility of this method is demonstrated with a study of metal-ion binding by PvuII endonuclease. Replacement of 74% (+/- 10%) of the Tyr residues in PvuII endonuclease by 3-fluorotyrosine produces an enzyme with Mg(II)-supported specific activity and sequence specificity that is indistinguishable from that of the native enzyme. Mn(II) supports residual activity of both the native and fluorinated enzymes; Ca(II) does not support activity in either enzyme, a result consistent with previous studies. 1H- and 19F-NMR spectroscopic studies reveal that while Mg(II) does not alter the enzyme conformation, the paramagnetic Mn(II) produces both short-range spectral broadening and longer range changes in chemical shift. Most interestingly, Ca(II) binding perturbs a larger number of different resonances than Mn(II). Coupled with earlier mutagenesis studies that place Ca(II) in the active site [Nastri, H. G., Evans, P.D., Walker, I.H. & Riggs, P.D. (1997) J. Biol. Chem. 272, 25761-25767], these data suggest that the enzyme makes conformational adjustments to accommodate the distinct geometric preferences of Ca(II) and may play a role in the inability of this metal ion to support activity in restriction enzymes.  (+info)

The aconitase of yeast. V. The reconstitution of yeast aconitase. (5/550)

The apoenzyme of yeast aconitase [EC 4.2.1.3] was prepared by treatment of yeast aconitase with sodium mersalyl, followed by passage by passage of the reaction mixture through a column of Dowex A-1 and gel filtration on Sephadex G-25. The apoenzyme had no aconitase activity, but the active enzyme could be reconstituted by treatment of the apoenzyme with ferrous ions and sodium sulfide in the presence of 2-mercapto-ethanol. The reconstituted active enzyme was isolated by DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration from the reaction mixture. The reconstituted enzyme was identical with the original untreated enzyme in terms of specific activity, iron content and spectral characteristics, but not in terms of labile sulfur content. A significant difference in visible spectra between the holo- and apoenzymes appeared to be due to the difference in iron and labile sulfur contents between the two proteins.  (+info)

Rapid PCR test for discriminating between Candida albicans and Candida dubliniensis isolates using primers derived from the pH-regulated PHR1 and PHR2 genes of C. albicans. (6/550)

The development of a satisfactory means to reliably distinguish between the two closely related species Candida albicans and Candida dubliniensis in the clinical mycology laboratory has proved difficult because these two species are phenotypically so similar. In this study, we have detected homologues of the pH-regulated C. albicans PHR1 and PHR2 genes in C. dubliniensis. Restriction fragment length polymorphism analysis suggests that there are significant sequence differences between the genes of the two species. In order to exploit this apparent difference, oligonucleotide primers based on the coding sequence of the C. albicans PHR1 structural gene were designed and used in PCR experiments. Use of these primers with C. albicans template DNA from 17 strains yielded a predicted 1.6-kb product, while C. dubliniensis template DNA from 19 strains yielded no product. We therefore propose that PCR using these primers is a rapid and reliable means of distinguishing the two germ tube- and chlamydospore-producing species C. albicans and C. dubliniensis.  (+info)

A novel 35 kDa frog liver acid metallophosphatase. (7/550)

The lower molecular weight (35 kDa) acid phosphatase from the frog (Rana esculenta) liver is a glycometalloenzyme susceptible to activation by reducing agents and displaying tartrate and fluoride resistance. Metal chelators (EDTA, 1,10-phenanthroline) inactivate the enzyme reversibly in a time- and temperature-dependent manner. The apoenzyme is reactivated by divalent transition metal cations, i. e. cobalt, zinc, ferrous, manganese, cadmium and nickel to 130%, 75%, 63%, 62%, 55% and 34% of the original activity, respectively. Magnesium, calcium, cupric and ferric ions were shown to be ineffective in this process. Metal analysis by the emission spectrometry method (inductively coupled plasma-atomic emission spectrometry) revealed the presence of zinc, iron and magnesium. The time course of the apoenzyme reactivation, the stabilization effect and the relatively high resistance to oxidizing conditions indicate that the zinc ion is crucial for the enzyme activity. The presence of iron was additionally confirmed by the visible absorption spectrum of the enzyme with a shoulder at 417 nm and by the electron paramagnetic resonance line of high spin iron(III) with geff of 2.4. The active center containing only zinc or both zinc and iron ions is proposed. The frog liver lower molecular weight acid phosphatase is a novel metallophosphatase of lower vertebrate origin, distinct from the mammalian tartrate-resistant, purple acid phosphatases.  (+info)

Purification of beef kidney D-aspartate oxidase overexpressed in Escherichia coli and characterization of its redox potentials and oxidative activity towards agonists and antagonists of excitatory amino acid receptors. (8/550)

The flavoenzyme d-aspartate oxidase from beef kidney (DASPO, EC 1.4. 3.1) has been overexpressed in Escherichia coli. A purification procedure, faster than the one used for the enzyme from the natural source (bDASPO), has been set up yielding about 2 mg of pure recombinant protein (rDASPO) per each gram of wet E. coli paste. rDASPO has been shown to possess the same general biochemical properties of bDASPO, except that the former contains only FAD, while the latter is a mixture of two forms, one active containing FAD and one inactive containing 6-OH-FAD (9-20% depending on the preparation). This results in a slightly higher specific activity (about 15%) for rDASPO compared to bDASPO and in facilitated procedures for apoprotein preparation and reconstitution. Redox potentials of -97 mV and -157 mV were determined for free and l-(+)-tartrate complexed DASPO, respectively, in 0.1 M KPi, pH 7.0, 25 degrees C. The large positive shift in the redox potential of the coenzyme compared to free FAD (-207 mV) is in agreement with similar results obtained with other flavooxidases. rDASPO has been used to assess a possible oxidative activity of the enzyme towards a number of compounds used as agonists or antagonists of neurotransmitters, including d-aspartatic acid, d-glutamic acid, N-methyl-d-aspartic acid, d,l-cysteic acid, d-homocysteic acid, d, l-2-amino-3-phosphonopropanoic acid, d-alpha-aminoadipic acid, d-aspartic acid-beta-hydroxamate, glycyl-d-aspartic acid and cis-2, 3-piperidine dicarboxylic acid. Kinetic parameters for each substrate in 50 mM KPi, pH 7.4, 25 degrees C are reported.  (+info)

The invention discloses a device and method by which dry reagent enzyme based electrochemical biosensors, which are in a relatively mature form due to the extensive amount of development pioneered by the blood glucose monitoring industry, may be simply adapted to perform tests for blood coagulation, enzymatic activity, or immunochemical assays for antigens present in a fluid sample. In particular, the utility of combining apoenzyme based dry reagent electrochemical biosensors with apoenzyme reactivation technology is taught. This combination creates a novel combination test technology capable of detecting a wide range of different analytes, and operating in a wide variety of wet or dry, in vivo or in vitro environments.
Salmonella typhimurium encounters a variety of acid conditions during both its natural and pathogenic existence. The ability of this organism to respond transcriptionally to low pH is an area of active interest but little knowledge. As part of an ongoing investigation of low-pH adaptation, 18 pH-con …
3 3 THEN 330 280 L P r e v = L t 290 B i t e = l 300 D i f f e r i t = l . 0 E - 4 310 Mprev=Mt 320 GO TO 360 330 LPrev=10OE-6 340 D i f f c r i t = l . O05 360 MPrev=Mt 370 REM * I * ITERATION LOOP BEGINS * * * 380 M f r e e = M t / ( l + K l * L P r e v ÷ B 2 * L P r e v ~ 2 + B 3 * L P r e v ~ 3 ) 390 M l = M f r e e * K l * L P r e v 400 M l 2 = M f r e e * B 2 * L ~ r e v ~ 2 410 M13=Mfree*B3*LPrev~3 420 L ? r e e = L t - M I - 2 * M 1 2 - 3 * M 1 3 430 L d i f ? = L ? r e e - L P r e v 440 L P r e v = L P r e v ÷ B i t e * L d i ? Vallee, this series, Vol. 54, p. 446. [5] METAL-FREE ENZYMES 23 Special attention should be given to the chemical composition of solutions to be used for preparation and reconstitution of apoenzymes. Many of the buffers commonly employed are also metal-chelating agents at biological pH ranges. , cobalt. HEPES, a sulfonic acid derivative, has been successfully used as a buffer salt to prepare a number of apoenzymes. Metal-buffer binding constants of " G o o d " ...
PHR1山羊多克隆抗体(ab85706)可与大鼠样本反应并经WB实验严格验证。中国75%以上现货,所有产品均提供质保服务,可通过电话、电邮或微信获得本地专属技术支持。
Shop L-allo-isoleucine:holo-[CmaA peptidyl-carrier protein] ligase ELISA Kit, Recombinant Protein and L-allo-isoleucine:holo-[CmaA peptidyl-carrier protein] ligase Antibody at MyBioSource. Custom ELISA Kit, Recombinant Protein and Antibody are available.
CRY1_CULQU (B0WRR9 ), CRY1_SINAL (P40115 ), CRY2_ARATH (Q96524 ), CRY2_VIBCH (Q9KS67 ), CRYD_GLOVI (Q7NMD1 ), CRYD_OSTTA (Q5IFN2 ), CRYD_RHOBA (Q7UJB1 ), CRYD_SYNY3 (P77967 ), PHRA_AGRFC (A9CJC9 ), PHR_BACPE (Q04449 ), PHR_BUCAI (P57386 ), PHR_BUCBP (Q89AJ9 ), PHR_ECOLI (P00914 ), PHR_HALSA (Q9HQ46 ), PHR_NEUCR (P27526 ), PHR_SALTY (P25078 ), PHR_STRGR (P12768 ), PHR_SYNP6 (P05327 ), PHR_SYNY3 (Q55081 ), PHR_THET2 (P61496 ), PHR_THET8 (P61497 ), PHR_VIBCH (Q9KNA8 ), PHR_YEAST (P05066 ...
NO diffuses to the adjacent smooth muscle where it interacts with different receptor molecules, of which the sGC is the best characterized and presumably most important one with regard to control of vessel tone and smooth muscle proliferation. The catalytically active holoenzyme exists as an obligate heterodimer consisting of 1 α and 1 β subunit and a noncovalently bound ferrous heme.9 The most abundant isoform in mammalian tissues is the α1 (73 to 78 kDa)/β1 (70 kDa) heterodimer. Significant protein expression of 2 other homologues subunits has only been detected in the human placenta (α2)10,11 and kidney (β2).12 At the genomic level, a dominant-negative splice variant of α2 classified as α2i has been detected.13 The interspecies homology of the individual subunits is high, whereas the intersubunit homology is lower.14 In contrast to α1 and β1, the biological significance of α2, α2I, and β2 is still obscure. The α2 subunit has recently been shown to be linked to cerebral ...
Antitoxic Unit [Ger. Antitoxineinheit]; Apoenzyme; Aryepiglottic; Atherosclerotic Encephalopathy; Atrial Ectopic [heart Beat]; Avian ...
Plasmid pHR iSH-YFP-PIF from Dr. Wendell Lims lab contains the inserts p85 iSH2 and PIF6 1-100 and is published in Nat Methods. 2011 Sep 11;8(10):837-9. doi: 10.1038/nmeth.1700. This plasmid is available through Addgene.
command in MATLAB. You can launch a pre-configured optimization task in Response Optimization Tool by first opening the model and by double-clicking on the orange block at the bottom of the model. From the Response Optimization Tool, press the Plot Model Response button to simulate the model and show how well the initial design satisfies the design requirements.. ...
1HVA: Engineering the zinc binding site of human carbonic anhydrase II: structure of the His-94Cys apoenzyme in a new crystalline form.
1AH4: A specificity pocket inferred from the crystal structures of the complexes of aldose reductase with the pharmaceutically important inhibitors tolrestat and sorbinil.
Difluoro-oxaloacetate interacts with the aldimine form of aspartate transaminase to give a complex, the dissociation constant of which has been determined spectrophotometrically and by 19F n.m.r. (nuclear magnetic resonance). The 19F n.m.r. line-width-pH and chemical-shift-pH profiles of difluoro-oxaloacetate in the presence of the aldimine form of the enzyme both show inflexion points in the pH5 and pH8 regions, which may arise from variations in the binding of difluoro-oxaloacetate as specific groups on the enzyme are successively protonated. Difluoro-oxaloacetate also interacts with apoenzyme to form a complex, the dissociation constant of which was determined by 19F n.m.r. The 19F n.m.r. line-width-pH and chemical-shift-pH profiles of difluoro-oxaloacetate in the presence of apoenzyme show a single inflexion point in the region of pH8. The absence, in this case, of an inflexion in the pH5 region indicates that the latter, present in the corresponding profiles for the aldimine form of the ...
... 3.65 (p,0.001) for 16, 24, and 32 weeks, respectively, compared to the 0 weeks
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This Valentines weekend some American zoos are offering an adults-only opportunity to discover animals amorous antics, and perhaps pick up a few tips.
Citation: Lee, L.F., Silva, R.F., Heidari, M., Reddy, S. 2010. Studies on Mareks Disease Virus Encoded Ribonucleotide Reductase. American Association of Avian Pathologists Symposium and Scientific Program, August 1-4, 2010, Atlanta, Georgia. Paper No. 9410-2. Interpretive Summary: Technical Abstract: Ribonucleotide reductase (RR) is an essential enzyme for the conversion of ribonucleotides to deoxyribonucleotides in prokaryotic and eukaryotic cells. The enzyme consists of two subunits namely RR1 and RR2, both of which associate to form an active holoenzyme. Herpesviruses express a functional RR required for viral pathogenesis and reactivation from latency in infected host. In pseudorabies virus, mutants deficient in RR were shown to be avirulent for pigs and capable for protecting pigs against disease. Mareks disease virus (MDV) also encodes a RR enzyme, which has 21 discrete blocks of amino acid homologous to other herpes viruses. These homologous blocks of amino acids are important sites for ...
Involved in the biogenesis of TorA. Acts on TorA before the insertion of the molybdenum cofactor and, as a result, probably favors a conformation of the apoenzyme that is competent for acquiring the cofactor.
The aim of this study was to identify the cardiac oxidoreductases involved in the metabolism of 4-hydroxy-2-trans-nonenal (HNE), an α,β unsaturated aldehyde generated during the peroxidation of ω-6 polyunsaturated fatty acids. In homogenates of bovine, human and rat ventricles the primary pyridine coenzyme-linked metabolism of HNE was associated with NADPH oxidation. The NADPH-dependent enzyme catalysing HNE reduction was purified to homogeneity from bovine heart. The purified enzyme displayed kinetic and immunological properties identical with the polyol pathway enzyme aldose reductase (AR), and catalysed the reduction of HNE to its alcohol 1,4-dihydroxynonene (DHN), with a Km of 7±2 μM. In the presence of NADP the enzyme did not catalyse the oxidation of DHN. During catalysis, HNE did not cause inactivation of AR. Nevertheless when the apoenzyme was incubated with HNE a dissociable complex was formed between the enzyme and HNE, followed by irreversible loss of activity. Inactivation of ...
Complete information for HCCS gene (Protein Coding), Holocytochrome C Synthase, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
myo-Inositol oxygenase from hog kidney. I. Purification and characterization of the oxygenase and of an enzyme complex containing the oxygenase and D-glucuronate reductase ...
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Apoenzymes becomes active enzymes on addition of a cofactor. Cofactors can be either inorganic (e.g., metal ions and iron- ... An apoenzyme (or, generally, an apoprotein) is the protein without any small-molecule cofactors, substrates, or inhibitors ...
Nair, P.M.; Vining, L.C. (1965). "Isophenoxazine synthase apoenzyme from Pycnoporus coccineus". Biochim. Biophys. Acta. 96: 318 ...
I. Purification of the apoenzyme and synthetase; characteristics of the reaction". J. Biol. Chem. 239: 2858-2864. Molecular and ...
However, the apoenzyme without copper is unstable. Apoceruloplasmin is largely degraded intracellularly in the hepatocyte and ...
Groen, B.W.; van Kleef, M.A.; Duine, J.A. (1986). "Quinohaemoprotein alcohol dehydrogenase apoenzyme from Pseudomonas ...
Methylmalonyl-CoA mutase is a mitochondrial homodimer apoenzyme (EC. 5. 4.99.2) that focuses on the catalysis of methylmalonyl ...
Isolation of the holo- and apoenzymes and conversion of the apoenzyme to the holoenzyme". J. Biol. Chem. 260 (2): 1311-1325. ...
A complex of the apoenzyme and citrate at 1.87 A resolution". Journal of Molecular Biology. 226 (3): 867-82. doi:10.1016/0022- ...
Crystallographic studies have helped elucidate the apoenzyme structure of phosphopentose epimerase. Results of these studies ...
Recny, M.A.; Hager, L.P. (1982). "Reconstitution of native Escherichia coli pyruvate oxidase from apoenzyme monomers and FAD". ...
"Reconstitution of native Escherichia coli pyruvate oxidase from apoenzyme monomers and FAD". J. Biol. Chem. 257 (21): 12878-86 ...
2. Spectroscopic Studies on the Apoenzyme and the Monomeric and Dimeric Forms". European Journal of Biochemistry. 33 (2): 271-8 ...
Enzymes that require a cofactor but do not have one bound are called apoenzymes or apoproteins. An enzyme together with the ...
Kamei S, Ohkubo A, Yamanaka M (1979). "Apoenzyme of aspartate aminotransferase isozymes in serum and its diagnostic usefullness ...
The apoenzyme form, lacking the zinc cofactor, has a molecular weight of 382815.4 g/mol. The chloride ion and the 3,6,9,12,15, ... H2S The apoenzyme form, lacking the zinc cofactor, has a molecular weight of 382815.4 g/mol. The chloride ion and the 3,6,9,12, ...
... preparation and characterization of the apoenzyme and monomer-dimer equilibrium". Arch. Biochem. Biophys. 337 (1): 89-95. doi: ...
... and the properties of the apoenzyme subunits". Acta Biochim. Pol. 13 (4): 311-28. PMID 5962440. SMILEY KL, SOBOLOV M (1962). "A ...
Dewanti AR, Duine JA (1998). "Reconstitution of membrane-integrated quinoprotein glucose dehydrogenase apoenzyme with PQQ and ...
... the binding process of PQQ to the apoenzymes". Biosci. Biotechnol. Biochem. 59: 1548-1555. doi:10.1271/bbb.59.1548. Soluble ...
Three of these were of the wild type: the apoenzyme in 1S2T, the enzyme plus its magnesium ion cofactor in 1S2V, and the enzyme ... A mutant (D58A, in one of the active-site loops) was crystallized as an apoenzyme also (1S2U). From these structures, an active ...
In this system, the inactive form (the apoenzyme) becomes the active form (the holoenzyme) when the coenzyme binds. Examples of ...
This changes the active site from an open cleft in the apo-enzyme into a nearly solvent inaccessible pocket. This theme of ... Structural studies of P. aeruginosa PMM/PGM by X-ray crystallography have been conducted as both apo-enzyme and as protein- ...
An inactive enzyme without the cofactor is called an apoenzyme, while the complete enzyme with cofactor is called a holoenzyme ...
MMAA protein favors association with the MCM apoenzyme, and allows for the transfer of the AdoCbl cofactor to the enzyme active ... "Immunochemical studies of fibroblasts from patients with methylmalonyl-CoA mutase apoenzyme deficiency: detection of a mutation ...
Furthermore, it has been shown that the apoenzyme will still sample the 'closed' conformations of the ATPlid and AMPlid domains ...
... the binding process of PQQ to the apoenzymes". Biosci. Biotechnol. Biochem. 59: 1548-1555. doi:10.1271/bbb.59.1548. Soluble ...
Binding of cofactors to the apoenzyme showed the expected hysteresis. Without preincubation, the Km values for thiamin ...
Together, our data point to a gatekeeping role for MMAA by favoring complex formation with MUT apoenzyme for AdoCbl assembly ... Formation of a stable MMAA-MUT complex is nucleotide-selective for MMAA (GMPPNP over GDP) and apoenzyme-dependent for MUT. The ... Formation of a stable MMAA-MUT complex is nucleotide-selective for MMAA (GMPPNP over GDP) and apoenzyme-dependent for MUT. The ... Together, our data point to a gatekeeping role for MMAA by favoring complex formation with MUT apoenzyme for AdoCbl assembly ...
Unlike the enzymes from sheep, monkey, and human liver, which were converted to the apoenzyme upon treatment with L-cysteine ...
In particular, the utility of combining apoenzyme based dry reagent electrochemical biosensors with apoenzyme reactivation ... These PQQ apoenzyme prosthetic groups, in turn, bind to the electrode-bound GDH apoenzyme, and change the GDH apoenzyme into an ... the apoenzyme (4), (14) contains a reagent form of the antigen (9), (19) chemically coupled to apoenzyme (4), (14), and this ... Here the apoenzyme (1), which may be the apoenzyme form of glucose oxidase, or other enzyme, is mounted or otherwise associated ...
Crystal structure of a bacterial signal peptidase apoenzyme: implications for signal peptide binding and the Ser-Lys dyad ... CRYSTAL STRUCTURE OF A BACTERIAL SIGNAL PEPTIDASE APO-ENZYME, IMPLICATIONS FOR SIGNAL PEPTIDE BINDING AND THE SER-LYS DYAD ...
ENGINEERING THE ZINC BINDING SITE OF HUMAN CARBONIC ANHYDRASE II: STRUCTURE OF THE HIS-94-, CYS APOENZYME IN A NEW CRYSTALLINE ... Engineering the zinc binding site of human carbonic anhydrase II: structure of the His-94Cys apoenzyme in a new crystalline ... CYS APOENZYME IN A NEW CRYSTALLINE FORM ...
Interaction of Proteus mirabilis Urease Apoenzyme and Accessory Proteins Identified with Yeast Two-Hybrid Technology. Susan R. ... The urease gene cluster of P. mirabilis encodes three structural polypeptides, UreA, UreB, and UreC, which form the apoenzyme; ... 4); UreD was arbitrarily drawn contacting the apoenzyme face opposite UreA; there is no direct evidence for this structure. ... It is likely that some accessory proteins require physical contact with their respective apoenzyme or other coaccessory ...
... - reactivation. immunoassay system), strips are impregnated with the dry conjugate , ... Meaning of "apoenzyme" in the English dictionary. To add the top layer to the sandwich, the FAD-conjugated monoclonal mouse ... Typically, apoenzyme 21 will contain prosthetic binding site 22 and the enzyme active site 23 which, in the absence of the ... An apoenzyme 4 containing an active site 5 and a prosthetic group binding site 6and an artificially coupled reagent-ligand ...
Rhymes for apoenzymes. Found with a strict rhyme search. Searched for rhymes at the end of the words. Rhymebox - the rhyming ... More about apoenzymes. Knowledge Wikipedia Wiktionary Google Images Google Yahoo! Flickr Videos Google Yahoo! Youtube ...
What is an apoenzyme?. A: Apoenzymes are proteins that form active enzyme systems by combining with coenzymes and establishing ...
What is an apoenzyme?. A: Apoenzymes are proteins that form active enzyme systems by combining with coenzymes and establishing ...
4.2 Apoenzyme/cofactor reconstitution. Even though biotin/(S)Av couples certainly exhibit nearly ideal features in terms of ... by Nolte and co-workers who took advantage of the strong interactions involved in the reconstitution between an apoenzyme and ... binding and host guest recognition process, the apoenzyme/cofactor reconstitution strategy represents an interesting ...
b) The apoenzyme is a part of all enzymes.. c) Proenzymes are active enzymes. ...
In addition, the quinone is hydrogen-bonded to a water molecule not present in the apo enzyme (W5 in Fig. 2B) that bridges the ... In this paper we report the apoenzyme structures of human (at 1.7-Å resolution) and mouse (2.8 Å) QR1 and the complex of the ... This is caused in part by the lack of structural information about the apoenzyme (apo) containing only the FAD prosthetic group ...
Conformational features of the holo- and apo-enzyme forms of serine hydroxymethyl transferase. Indian Journal of Biochemistry ... Conformational features of the holo- and apo-enzyme forms of serine hydroxymethyl transferase. ...
Apoenzyme 9606 1.1.1.1 , Details 72 1M6W 1 A, B Glutathione-dependent formaldehyde dehydrogenase Apoenzyme 9606 1.1.1.1 , ...
Apo-Enzyme. 19.127 g 0.40%. 0.673. MU/g. pyrrolo-quinoline quinine. Co-Factor. 0.5329 g 0.01%. ...
Coordinate Synthesis of Heme and Apoenzyme in the Formation of Tryptophan Pyrrolase ...
0 (Apoenzymes); 0 (Bacterial Proteins); 0 (Benzoquinones); 0 (Carrier Proteins); 0 (Protein Aggregates); 0 (Recombinant ...
Worthington Tyrosine Decarboxylase, Apoenzyme [WLS004968-250MG] - UNSPSC Code(s):12352204Activates to at least 0.2 units per ... Worthington Tyrosine Decarboxylase, Apoenzyme. Price(USD):$109.20. *Ask Promo Code: Equl SKU. Product Name. UOM. Specification ...
a. Apoenzyme Reagents-1.5 μM apoglucose oxidase (U.S. Pat. No. 4,268,631), 100 μl/ml antiserum to glucose oxidase, 3.5 μl/ml ... Apoenzyme reactivation electrochemical detection method and assay. US9156787. Jul 24, 2014. Oct 13, 2015. Board Of Regents Of ... Apoenzyme reactivation electrochemical detection method and assay. US20070289880 *. Jan 22, 2007. Dec 20, 2007. Zweig Stephen E ... An apoenzyme reactivation immunoassay system (ARIS, see U.S. Pat. No. 4,238,565) was established for imipramine as follows:. 1 ...
Crystal structure of apoenzyme cAMP-dependent protein kinase catalytic subunit ... Crystal structure of apoenzyme cAMP-dependent protein kinase catalytic subunit; X-RAY DIFFRACTION 2.90 Å SMTL ID. 1j3h.1. ...
Study Set 16 Enzymes and Hormones flashcards from Languages 247365
Study Biological Molecules flashcards from Rachel Lorenzon
  • Together, our data point to a gatekeeping role for MMAA by favoring complex formation with MUT apoenzyme for AdoCbl assembly and releasing the AdoCbl-loaded holoenzyme from the complex, in a GTP-dependent manner. (ox.ac.uk)
  • Formation of a stable MMAA-MUT complex is nucleotide-selective for MMAA (GMPPNP over GDP) and apoenzyme-dependent for MUT. (ox.ac.uk)
  • When antigenic test ligands 11 are added to the system, they compete for binding between the antigenic reagent ligand group 19 previously coupled to the apoenzyme 14breaking the bond between the antigenic reagent ligand group 19 and the antibody The next steps of the reaction are shown in 21immunoassay25262728 and These free FAD-antibodies bind to the apoglucose oxidase in the neighboring beads, creating active glucose oxidase. (yalasarat.info)
  • wherein said complex is on a surface that is spatially separated from the region or regions of the apparatus where the apoenzyme or inactive form of said electrochemical enzyme are located. (google.com)
  • 1,10-Phenanthroline is an inhibitor of metallopeptidases, with one of the first observed instances reported in carboxypeptidase A. Inhibition of the enzyme occurs by removal and chelation of the metal ion required for catalytic activity, leaving an inactive apoenzyme. (wikipedia.org)
  • In this paper we report the apoenzyme structures of human (at 1.7-Å resolution) and mouse (2.8 Å) QR1 and the complex of the human enzyme with the substrate duroquinone (2.5 Å) (2,3,5,6-tetramethyl- p -benzoquinone). (pnas.org)
  • The crystal structures of the human CDK2 apoenzyme and its Mg2+ ATP complex have been determined to 2.4 A resolution. (nih.gov)