*  Chinoproteina glucosio deidrogenasi - Wikipedia

Si tratta di una chinoproteina contenente PQQ, che catalizza l'ossidazione diretta da D-glucosio a D-gluconato nello spazio ... A covalent cofactor-inhibitor complex, in Proc. Natl. Acad. Sci. USA, vol. 96, 1999, pp. 11787-11791, Entrez PubMed 10518528. ... Dewanti, A.R. and Duine, J.A., Reconstitution of membrane-integrated quinoprotein glucose dehydrogenase apoenzyme with PQQ and ...

*  PQQ 20mg | Secom.ro

PQQ 20mg - Contribuie la încetinirea procesului de îmbătrânire celulară și la protecția sistemelor nervos și cardiovascular. ... Pirolochinolin chinona (PQQ) este un cofactor in ciclul redox si un nutrient esential, fiind implicata in generarea, ... PQQ actioneaza direct asupra enzimelor-cheie din mitocondrii, producatoare de energie in celule. Ca urmare, PQQ imbunatateste ... In urma acestei calitati unice, PQQ vine sa sustina sanatatea si longevitatea umana prin reducerea efectelor imbatranirii. Pe ...

*  PQQ: A Vital Nutrient for Mitochondrial Health, Memory, & Metabolism - Naturopathic Doctor News and Review

PQQ is a Vital Nutrient. PQQ stimulates growth and serves as a cofactor for a special class of enzymes involved in cellular ... before and 72 hours after being administered a daily dose of PQQ (0.3 mg PQQ/kg).20 PQQ supplementation resulted in significant ... PQQ is active on its own, and in most people under 50 years of age there may be no need for simultaneous use of PQQ and CoQ10 ... PQQ Activates AMPk and Lowers LDL-C. PQQ activates AMPk, an enzyme that is found inside living cells that serves as a "master ...

*  Toxics | Free Full-Text | The Chemistry and Toxicology of Depleted Uranium | HTML

Vanengelen et al. [15] reported the coordination of the uranyl ion with pyrroloquinoline quinone (PQQ) cofactor and its ... PQQ) with bonding of the uranyl ion to the carbonyl oxygen, the pyridine nitrogen and the quinone oxygen of the ... Uranium exerts acute toxicity by binding to pyrroloquinole quinine cofactor. Environ. Sci. Techol. 2011, 45, 937-942. [Google ... pyrroloquinoline quinone cofactor was proposed. They suggested, "…UO22+ may also coordinate with enzymes or enzyme cofactors ...

*  "Nutritional Complementation of Oxidative Glucose Metabolism in <i>Esch" by Michael Adamowicz, Tyrrell Conway...

PQQ is the cofactor for the periplasmic enzyme glucose dehydrogenase, which converts glucose to gluconate. Aerobically, E. coli ... Adaptation to PQQ-dependent growth exhibited long lag periods, except under low-phosphate conditions, in which the PhoE porin ... In the presence of 5% sodium dodecyl sulfate, PQQ no longer acted as a growth factor. Sodium dodecyl sulfate inhibited the ... ZSC113 grew on glucose plus PQQ with a generation time of 65 min, a generation time about the same as that for wildtype E. coli ...

*  Pfam: Family: GSDH (PF07995)

The enzyme is a calcium-dependent homodimer which uses PQQ as a cofactor [PUBMED:10508152]. ... PQQ PQQ_2 PQQ_3 RAG2 RCC1 RCC1_2 Reg_prop SBBP SBP56 SdiA-regulated SGL Str_synth TcdB_toxin_midN TolB_like VCBS WD40 WD40_3 ...

*  Bridging the Gap with Bioelectronics

PQQ)-flavinadenine dinucleotide (FAD). When the immobilized enzyme oxidizes glucose, electrons are shuttled from its cofactor ... the substrates of cofactor-dependent redox enzymes. A relevant enzyme depleted of its cofactor an apo-enzyme is reconstituted ... "We have also constructed a noncompartmentaalized biofuel cell employing electrodes functionalized with PQQ-FAD- glucose oxidase ... FAD to PQQ to the electrode. "This technology could be employed in implantable devices for continuous blood glucose monitoring ...

*  What does PQ mean?

pqq cofactor. *pr. *pr man. *prætor. *prætorian guard. Alternative searches for PQ:. *Search for Synonyms for PQ ...

*  Electrical contacting of flavoenzymes and NAD(P)+-dependent enzymes by reconstitution and affinity interactions on...

The reconstitution of apo-glucose oxidase, apo-GOx, on a FAD cofactor linked to a pyrroloquinoline quinone (PQQ) phenylboronic ... cofactor is linked to the PQQ-phenylboronic acid by two different binding modes. The integration of the LDH with the two NAD ... cofactor configurations yields enzyme assemblies differing by 1 order of magnitude in their bioelectrocatalytic activities. ...

*  Mito-PQQ

PQQ), a water-soluble, vitamin-like compound, and Rhodiola rosea, a popular adaptogen. PQQ is an enzyme cofactor possessing ... Mito-PQQ™ is designed to help support optimal mitochondrial biogenesis, which is critical for the promotion of healthy aging, ...

*  Buy PQQ Plus (30 Vegetarian Capsules) - Douglas Laboratories - Pyrrolo

PQQ Plus (30 Vegetarian Capsules) - Douglas Laboratories. For all your vitamins, superfoods and nutritional supplements. Lowest ... Pyrrolloquinoline (PQQ) is an enzyme cofactor functionally related to the B vitamin family. First recognized as an enzyme ... PQQ Plus supplies 20 mg pyrroloquinoline quinone (PQQ), the novel compound that some consider to be a newly discovered vitamin ... You're reviewing: PQQ Plus (30 Vegetarian Capsules) - Douglas Laboratories. How do you rate this product? * 1 star. 2 stars. 3 ...

*  EarthTurns - Douglas Laboratories PQQ Plus - 30 Vegetarian Capsules - Free Shipping

PQQ) and 50 mg of alpha glycerylphosphoryl choline (alpha GPC) for optimal neurological health. ... Douglas Laboratories PQQ Plus supplies 20 mg pyrroloquinoline quinone ( ... PQQ Plus Function. Pyrrolloquinoline (PQQ) is an enzyme cofactor functionally related to the B vitamin family. First recognized ... PQQ Plus Indications PQQ Plus may be a useful dietary supplement for individuals wishing to support healthy cognitive and ...

*  Caloric Restriction Mimetics | Life Extension

Similarly, pyrroloquinoline quinone (PQQ), a bacterial electron carrier154 and cofactor for several bacterial enzymes (and at ...

*  Redox-Active Amino Acids in Biology, Volume 258 - 1st Edition

L.M. Sayre and Y. Lee, Catalytic Aerobic Deamination of Activated Primary Amines by a Model for the Quinone Cofactor of ... R. Flackiger, M.A. Paz, and P.M. Gallop, Redox-Cycling Detection of Dialyzable Pyrroloquinoline Quinone (PQQ) and Quinoproteins ... S. Itoh and Y. Ohshiro, Model Studies of Cofactor Tryptophan Tryptophylquinone (TTQ). ... Use of Rapid Kinetics Methods to Study the Assembly of the Diferric-Tyrosyl Radical Cofactor of E. coli Ribonucleotide ...

*  Boli, afectiuni

Coenzyme PQQ. Sulpiment alimentar, co-factor redox. Conduce la regenerarea mitocondriilor obosite. Conduce la generarea de noi ...

*  Patent US8118991 - Apoenzyme reactivation electrochemical detection method and assay - Google Patents

Other apoenzymes and cofactor requiring enzymes suitable for the present invention require other cofactor molecules. Some of ... The antibody coupled aminoacylase enzyme produces a GDH apoenzyme prosthetic group PQQ. These PQQ apoenzyme prosthetic groups, ... said cofactor, prosthetic group or activation moiety being present in the form of at least one complex that contains at least ... said cofactor, prosthetic group or activation moiety being present in the form of at least one complex that that contains at ...

*  Institute of Biochemistry - Vilnius University

Application of NAD- And PQQ-Dependent Alcohol Dehydrogenases for Bioconversion. Dr. R. Meškys. 2011-2014. ... are attractive catalysts because of their wide substrate specificity and non-diffusible cofactor. ADH IIG from Pseudomonas ... Creation and Investigation of Bioelectrocatalytical Systems Based on PQQ-Dehydrogenases and Fungal Laccases. Mathematical ...


PQQ is induced by exercise so it stands to reason that memory and cognition can also be improved and expanded by using PQQ as ... Brendel C, Gelman L, Auwerx J (June 2002). "Multiprotein bridging factor-1 (MBF-1) is a cofactor for nuclear receptors that ... K. - I see there is PQQ in vegetables like celery and parsley (and natto, yuck). Is it possible to get enough PQQ from food ... Remember, I just introduced you PQQ in my last blog. This is why many researchers and clinicians have called PQQ the "exercise ...

*  Treatment of the Fluoroquinolone-Associated Disability: The Pathobiochemical Implications

These results point to high ability of FQs to absorb Fe2/3+ and reduce the activity of enzymes which use Fe2/3+ as a cofactor. ... PQQ) [107, 108]. This substance is also postulated to be OS protective [109].(e)Removing FQs permanently accumulated in the ... Mn2+ seems to be very important, because it is a cofactor of mitochondrial SOD2 being the first barrier against O2− and ... It must be pointed that cytochromes are the other important proteins which use Fe2/3+ in hem groups as a cofactor. Thus, the ...

*  Brevet US7045054 - Small volume biosensor for continuous analyte monitoring - Google Brevets

In a solution of 50 mM Pyrrole-3-acetic acid, 0.05 mM PQQ, and 50 mM KCl in 0.1 M HEPES buffer, 5 mg/mL of GDH was dissolved. ... Alternatively the enzyme(s), the enzyme cofactor(s) and the electron mediator(s) can be selected to have a molecular weight ... The GDH/PQQ substantially does not react with any endogenous substrate other than the analyte of interest. This allows the ... In a solution of 50 mM Pyrrole-3-acetic acid, 10 mM Osmium modified pyrrole derivative 10, 0.05 mM PQQ and 50 mM KCl in 0.1 M ...

*  Vitamin Scripts - Cognitive Support

PQQ Complex 30 vegcaps (P3168). Price: $42.00. PQQ Complex 30 vegcaps (P3168) ...

*  Now Foods, NADH, 10 mg, 60 Veg Capsules - iHerb.com

NADH is an essential cofactor for hundreds of biochemical reactions, and is used extensively in the production of cellular ... Doctor's Best, Best PQQ, 20 mg, 30 Veggie Caps 57. $19.28. MRM, Acetyl L-Carnitine, 500 mg, 60 Veggie Caps. 611 ...

(1/143) Characterization of the membrane quinoprotein glucose dehydrogenase from Escherichia coli and characterization of a site-directed mutant in which histidine-262 has been changed to tyrosine.

The requirements for substrate binding in the quinoprotein glucose dehydrogenase (GDH) in the membranes of Escherichia coli are described, together with the changes in activity in a site-directed mutant in which His262 has been altered to a tyrosine residue (H262Y-GDH). The differences in catalytic efficiency between substrates are mainly related to differences in their affinity for the enzyme. Remarkably, it appears that, if a hexose is able to bind in the active site, then it is also oxidized, whereas some pentoses are able to bind (and act as competitive inhibitors), but are not substrates. The activation energies for the oxidation of hexoses and pentoses are almost identical. In a previously published model of the enzyme, His262 is at the entrance to the active site and appears to be important in holding the prosthetic group pyrroloquinoline quinone (PQQ) in place, and it has been suggested that it might play a role in electron transfer from the reduced PQQ to the ubiquinone in the membrane. The H262Y-GDH has a greatly diminished catalytic efficiency for all substrates, which is mainly due to a marked decrease in their affinities for the enzyme, but the rate of electron transfer to oxygen is unaffected. During the processing of the PQQ into the apoenzyme to give active enzyme, its affinity is markedly dependent on the pH, four groups with pK values between pH7 and pH8 being involved. Identical results were obtained with H262Y-GDH, showing that His262 it is not directly involved in this process.  (+info)

(2/143) Functions of amino acid residues in the active site of Escherichia coli pyrroloquinoline quinone-containing quinoprotein glucose dehydrogenase.

Several mutants of quinoprotein glucose dehydrogenase (GDH) in Escherichia coli, located around its cofactor pyrroloquinoline quinone (PQQ), were constructed by site-specific mutagenesis and characterized by enzymatic and kinetic analyses. Of these, critical mutants were further characterized after purification or by different amino acid substitutions. H262A mutant showed reduced affinities both for glucose and PQQ without significant effect on glucose oxidase activity, indicating that His-262 occurs very close to PQQ and glucose, but is not the electron acceptor from PQQH(2). W404A and W404F showed pronounced reductions of affinity for PQQ, and the latter rather than the former had equivalent glucose oxidase activity to the wild type, suggesting that Trp-404 may be a support for PQQ and important for the positioning of PQQ. D466N, D466E, and K493A showed very low glucose oxidase activities without influence on the affinity for PQQ. Judging from the enzyme activities of D466E and K493A, as well as their absorption spectra of PQQ during glucose oxidation, we conclude that Asp-466 initiates glucose oxidation reaction by abstraction of a proton from glucose and Lys-493 is involved in electron transfer from PQQH(2).  (+info)

(3/143) Novel role for the NMDA receptor redox modulatory site in the pathophysiology of seizures.

Redox-active compounds modulate NMDA receptors (NMDARs) such that reduction of NMDAR redox sites increases, and oxidation decreases, NMDAR-mediated activity. Because NMDARs contribute to the pathophysiology of seizures, redox-active compounds also may modulate seizure activity. We report that the oxidant 5, 5'-dithio-bis(2-nitrobenzoic acid) (DTNB) and the redox cofactor pyrroloquinoline quinone (PQQ) suppressed low Mg(2+)-induced hippocampal epileptiform activity in vitro. Additionally, in slices exposed to 4-7 microM bicuculline, DTNB and PQQ reversed the potentiation of evoked epileptiform responses by the reductants dithiothreitol and Tris(2-carboxyethyl)phosphine (TCEP). NMDA-evoked whole-cell currents in CA1 neurons in slices were increased by TCEP and subsequently decreased by DTNB or PQQ at the same concentrations that modulated epileptiform activity. However, DTNB and PQQ had little effect on baseline NMDA-evoked currents in control medium, and PQQ did not alter NMDAR-dependent long-term potentiation. In contrast, in slices returned to control medium after low Mg(2+)-induced ictal activity, DTNB significantly inhibited NMDAR-mediated currents, indicating endogenous reduction of NMDAR redox sites under this epileptogenic condition. These data suggested that PQQ and DTNB suppressed spontaneous ictal activity by reversing pathological NMDAR redox potentiation without inhibiting physiological NMDAR function. In vivo, PQQ decreased the duration of chemoconvulsant-induced seizures in rat pups with no effect on baseline behavior. Our results reveal endogenous potentiation of NMDAR function via mass reduction of redox sites as a novel mechanism that may enhance epileptogenesis and facilitate the transition to status epilepticus. The results further suggest that redox-active compounds may have therapeutic use by reversing NMDAR-mediated pathophysiology without blocking physiological NMDAR function.  (+info)

(4/143) Physiological importance of quinoenzymes and the O-quinone family of cofactors.

O-quinone cofactors derived from tyrosine and tryptophan are involved in novel biological reactions that range from oxidative deaminations to free-radical redox reactions. The formation of each of these cofactors appears to involve post-translational modifications of either tyrosine or tryptophan residues. The modifications result in cofactors, such as topaquinone (TPQ), tryptophan tryptophylquinone (TTQ), lysine tyrosylquinone (LTQ) or the copper-complexed cysteinyl-tyrosyl radical from metal-catalyzed reactions. Pyrroloquinoline quinone (PQQ) appears to be formed from the annulation of peptidyl glutamic acid and tyrosine residues stemming from their modification as components of a precursor peptide substrate. PQQ, a primary focus of this review, has invoked considerable interest because of its presence in foods, antioxidant properties and role as a growth-promoting factor. Although no enzymes in animals have been identified that exclusively utilize PQQ, oral supplementation of PQQ in nanomolar amounts increases the responsiveness of B- and T-cells to mitogens and improves neurologic function and reproductive outcome in rodents. Regarding TPQ and LTQ, a case may be made that the formation of TPQ and LTQ is also influenced by nutritional status, specifically dietary copper. For at least one of the amine oxidases, lysyl oxidase, enzymatic activity correlates directly with copper intake. TPQ and LTQ are generated following the incorporation of copper by a process that involves the two-step oxidation of a specified tyrosyl residue to first peptidyl dopa and then peptidyl topaquinone to generate active enzymes, generally classed as "quinoenzymes." Limited attention is also paid to TTQ and the copper-complexed cysteinyl-tyrosyl radical, cofactors important to fungal and bacterial redox processes.  (+info)

(5/143) Structural requirements of pyrroloquinoline quinone dependent enzymatic reactions.

On the basis of crystal structures of the pyrroloquinoline quinone (PQQ) dependent enzymes methanol dehydrogenase (MDH) and soluble glucose dehydrogenase (s-GDH), different catalytic mechanisms have been proposed. However, several lines of biochemical and kinetic evidence are strikingly similar for both enzymes. To resolve this discrepancy, we have compared the structures of these enzymes in complex with their natural substrates in an attempt to bring them in line with a single reaction mechanism. In both proteins, PQQ is located in the center of the molecule near the axis of pseudo-symmetry. In spite of the absence of significant sequence homology, the overall binding of PQQ in the respective active sites is similar. Hydrogen bonding interactions are made with polar protein side chains in the plane of the cofactor, whereas hydrophobic stacking interactions are important below and above PQQ. One Arg side chain and one calcium ion are ligated to the ortho-quinone group of PQQ in an identical fashion in either active site, in agreement with their proposed catalytic function of polarizing the PQQ C5-O5 bond. The substrates are bound in a similar position above PQQ and within hydrogen bond distance of the putative general bases Asp297 (MDH) and His144 (s-GDH). On the basis of these similarities, we propose that MDH and s-GDH react with their substrates through an identical mechanism, comprising general base-catalyzed hydride transfer from the substrate to PQQ and subsequent tautomerization of the PQQ intermediate to reduced PQQ.  (+info)

(6/143) Synthesis of [(14)C]pyrroloquinoline quinone (PQQ) in E. coli using genes for PQQ synthesis from K. pneumoniae.

Radiochemical forms of pyrroloquinoline quinone (PQQ) are of utility in studies to determine the metabolic role and fate of PQQ in biological systems. Accordingly, we have synthesized [(14)C]PQQ using a tyrosine auxotrophic strain of Escherichia coli (AT2471). A construct containing the six genes required for PQQ synthesis from Klebsiella pneumoniae was used to transform the auxotrophic strain of E. coli. E. coli were then grown in minimal M9 medium containing 3.7x10(9) Bq/mmol [(14)C]tyrosine. At confluence, the medium was collected and applied to a DEAE A-25 anionic exchange column; [(14)C]PQQ was eluted using a KCl gradient (0-2 M in 0.1 M potassium phosphate buffer, pH 7.0). Radioactivity co-eluting as PQQ was next pooled, acidified and passed through a C-18 column; [(14)C]PQQ was eluted with a phosphate buffer (0.1 M, pH 7.0). Reverse phase HPLC (C-18) using either the ion-pairing agent trifluoroacetic acid (0. 1%) and an acetonitrile gradient or phosphoric acid and a methanol gradient were used to isolate [(14)C]PQQ. Fractions were collected and analyzed by liquid scintillation counting. (14)C-labelled compounds isolated from the medium eluted corresponding to the elution of various tyrosine-derived products or PQQ. The radioactive compound corresponding to PQQ was also reacted with acetone to form 5-acetonyl-PQQ, which co-eluted with a 5-acetonyl-PQQ standard, as a validation of [(14)C]PQQ synthesis. The specific activity of synthesized [(14)C]PQQ was 3.7x10(9) Bq/mmol [(14)C]PQQ, equal to that of [U-(14)C]tyrosine initially added to the medium.  (+info)

(7/143) Ca(2+) stabilizes the semiquinone radical of pyrroloquinoline quinone.

Spectroelectrochemical studies were performed on the interaction between Ca(2+) and pyrroloquinoline quinone (PQQ) in soluble glucose dehydrogenase (sGDH) and in the free state by applying a mediated continuous-flow column electrolytic spectroelectrochemical technique. The enzyme forms used were holo-sGDH (the holo-form of sGDH from Acinetobacter calcoaceticus) and an incompletely reconstituted form of this, holo-X, in which the PQQ-activating Ca(2+) is lacking. The spectroelectrochemical and ESR data clearly demonstrated the generation of the semiquinone radical of PQQ in holo-sGDH and in the free state in the presence of Ca(2+). In contrast, in the absence of Ca(2+) no semiquinone was observed, either for PQQ in the free state (at pH 7.0) or in the enzyme (holo-X). Incorporation of Ca(2+) into the active site of holo-X, yielding holo-sGDH, caused not only stabilization of the semiquinone form of PQQ but also a negative shift (of 26.5 mV) of the two-electron redox potential, indicating that the effect of Ca(2+) is stronger on the oxidized than on the reduced PQQ. Combining these data with the observations on the kinetic and chemical mechanisms, it was concluded that the strong stimulating effect of Ca(2+) on the activity of sGDH can be attributed to facilitation of certain kinetic steps, and not to improvement of the thermodynamics of substrate oxidation. The consequences of this conclusion are discussed for the oxidative as well as for the reductive part of the reaction of sGDH.  (+info)

(8/143) Membrane-associated quinoprotein formaldehyde dehydrogenase from Methylococcus capsulatus Bath.

A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159-167, 1999; Vorholt et al., J. Bacteriol. 180:5351-5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b(559/569) complex as the physiological electron acceptor.  (+info)


  • Pirolochinolin chinona (PQQ) este un cofactor in ciclul redox si un nutrient esential, fiind implicata in generarea, dezvoltarea si protectia celulara. (secom.ro)


  • PQQ actioneaza direct asupra enzimelor-cheie din mitocondrii, producatoare de energie in celule. (secom.ro)
  • One key action of PQQ involves a direct action on key enzymes in mitochondria. (ndnr.com)