72909-34-3Relevant articles and documents
Reaction of Reduced PQQ (PQQH2) and Molecular Oxygen
Itoh, Shinobu,Ohshiro, Yoshiki,Agawa, Toshio
, p. 1911 - 1914 (1986)
Reduced PQQ (PQQH2) is prepared by the reaction of PQQ with thiophenol, 1-benzyl-1,4-dihydronicotinamide (BNAH), sodium dithionite, or sodium borohydride.Oxidation of PQQH2 to PQQ by molecular oxygen in aqueous solutions is investigated kinetically.The oxidation is accelerated gradually with proceeding of the reaction, which may be attributed to the side reaction of PQQH2 and H2O2 produced by the reaction of PQQH2 and O2.As in fact, the yield of H2O2 is found to be 50percent based on PQQH2.Initial rate is first-order in oxygen concentration.The pH-rate profile suggests that an active species in the reaction is PQQH-.Autocatalysis of O2-. and PQQ itself is scarcely detected in this reaction.The mechanism of the oxidation is also discussed.
Unusual Ionic Bond and Solubility Mechanism of NanPQQ (n = 0-4) Crystals
Ikemoto, Kazuto,Sakamoto, Yuki,Tanaka, Rikako,Ogata, Koji,Matsushita, Nobuyuki,Nakamura, Shinichiro
, p. 4118 - 4123 (2017)
A comparative study of van der Waals and ionic crystals can provide vital information for the medical and food industries. In this work, we investigated the coenzyme pyrroloquinoline quinone (PQQ), which contains three carboxyl groups coupled to imidazole, pyridine, and quinone. Whole-crystal analysis (crystal-ome) was attempted for NanPQQ (n = 0-4) crystals. All deprotonation sites were found to be dependent on pKa except for the Na sites, which cannot be explained by pKa. The Na1PQQ crystal exhibited an unusual ionic bond, forming COOH-Na+ at one of the carboxyl sites in the structure. The difference in the solubility of the van der Waals and ionic crystals was also investigated, with a focus on the dissolution processes of Na0PQQ and Na2PQQ, by combining molecular dynamics simulations with experiments that define the crystal surfaces. This study is the first step toward developing a general rule to link the different types of crystal structures with different dissolution mechanisms and rates.
Multistep, eight-electron oxidation catalyzed by the cofactorless oxidase, PqqC: Identification of chemical intermediates and their dependence on molecular oxygen
Bonnot, Florence,Iavarone, Anthony T.,Klinman, Judith P.
, p. 4667 - 4675 (2013)
The final step of the biosynthesis of prokaryotic cofactor PQQ is catalyzed by PqqC, a cofactorless oxidase that brings about a ring closure and overall eight-electron oxidation of its substrate. Time-dependent acid quenching and subsequent high-performance liquid chromatography separation and mass spectrometric analyses of reaction mixtures were performed to correlate the structures of intermediates with previously observed UV-visible signatures. The reaction is composed of four stepwise oxidations: three steps use O2 as the two-electron acceptor, and the fourth uses hydrogen peroxide (H 2O2). The chemical nature of the intermediates, the stoichiometry of the reaction, and their dependence on the oxygen concentration indicate that the third oxidation uses the product, H2O2, from the preceding step to produce water. The last oxidation step can also be studied separately and is a reaction between O2 and PQQH2 trapped in the active site. This oxidation is approximately 10 times slower than the reoxidation of PQQH2 in solution. From the order of the four oxidation steps and their sensitivity to O2 concentration, we propose a progressive closure of the active site as the enzyme proceeds through its catalytic cycle.
PYRROLOQUINOLINE QUINONE MONOSODIUM AND METHOD FOR PRODUCING THE SAME, AND COMPOSITION COMPRISING THE SAME
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Paragraph 0097; 0098-0099, (2019/11/11)
The present invention provides pyrroloquinoline quinone monosodium having a structure represented by the following formula (1).
A method for synthesizing pyrroloquinoline quinone (by machine translation)
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Paragraph 0029; 0040; 0049, (2018/08/28)
The invention relates to a synthetic pyrroloquinoline quinone of the method, the method to pyruvic acid ethyl ester as the starting synthetic raw material, preparation pyrroloquinoline quinone. In the synthetic method of the present invention, compound 4 synthesis of compound 5 is the key step in the synthetic route, in the key step 5) in, the invention creative use of hexafluoro antimonate ion liquid, hexafluoro titanate ion liquid, six fluorine niobium acid salt ion liquid such as Lewis acid ionic liquid, the ionic liquid has the function of the reaction medium and the catalyst, thereby improving the response speed and the yield of this step. In addition, the invention preferably use the [BMIm] SbF6 Ionic liquid, [BMIm] SbF6 Ionic liquid and Sc (OTf)3 Can be formed of a higher catalytic activity [Sc (OTf)3 -x ] [SbF6 ], Can make the reaction efficiency is greatly improved, and the obtained reaction product in [BMIm] SbF6 The solubility of the ionic liquid in small, easily precipitated, so as to improve the reaction yield (can be up to 96%). (by machine translation)