Results 171 to 180 of about 4,234 (212)
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Analytical Biochemistry, 1996
Pyrroloquinoline quinone (PQQ) is a widely distributed redox-active cofactor and essential nutrient. For its detection in protein-free ultrafiltrates or dialysates, a highly sensitive amplification assay was developed on the basis of PQQ's ability to catalyze redox cycling at pH 10 in the presence of excess glycine, oxygen, and nitro blue tetrazolium ...
M A, Paz +4 more
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Pyrroloquinoline quinone (PQQ) is a widely distributed redox-active cofactor and essential nutrient. For its detection in protein-free ultrafiltrates or dialysates, a highly sensitive amplification assay was developed on the basis of PQQ's ability to catalyze redox cycling at pH 10 in the presence of excess glycine, oxygen, and nitro blue tetrazolium ...
M A, Paz +4 more
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Journal of the American Chemical Society, 2004
Pyrroloquinoline quinone (PQQ) is a tricyclic o-quinone, which serves as a cofactor in several enzyme-catalyzed redox reactions in certain bacteria. PQQ is also important for human health, and its role as a vitamin in mammals has recently been suggested. Although much is known about the function of enzymes that use PQQ as cofactor, relatively little is
Olafur T, Magnusson +4 more
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Pyrroloquinoline quinone (PQQ) is a tricyclic o-quinone, which serves as a cofactor in several enzyme-catalyzed redox reactions in certain bacteria. PQQ is also important for human health, and its role as a vitamin in mammals has recently been suggested. Although much is known about the function of enzymes that use PQQ as cofactor, relatively little is
Olafur T, Magnusson +4 more
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The PQQ-alcohol dehydrogenase of Gluconacetobacter diazotrophicus
International Journal of Food Microbiology, 2008The oxidation of ethanol to acetic acid is the most characteristic process in acetic acid bacteria. Gluconacetobacter diazotrophicus is rather unique among the acetic acid bacteria as it carries out nitrogen fixation and is a true endophyte, originally isolated from sugar cane. Aside its peculiar life style, Ga. diazotrophicus, possesses a constitutive
Saúl, Gómez-Manzo +5 more
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Identification and Quantification of PQQ
1989PQQ can occur in free form, as a C5-addition compound, as a condensation product with amino acids (e.g. an oxazole) and in an extractable or covalently bound form. Free, underivatized PQQ can be quantified by several chromatographic methods and biological assays. However, alternative analytical procedures had to be developed for the other cases. The so-
Robert A. van der Meer +2 more
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Methoxatin (PQQ) in guinea-pig neutrophils
Free Radical Biology and Medicine, 1994PQQ, also called methoxatin, has been isolated from guinea-pig neutrophils. The organic cations diphenyleneiodonium (DPI) and diphenyliodonium (BPI) and the aromatic o-diamine 4,5-dimethylphenylenediamine (DIMPDA) sequester synthetic PQQ and inhibit its redox-cycling activity in a model system.
A, Bishop +3 more
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The Chemistry and Biomimetics of PQQ
1989Chemical simulation of redox functions of PQQ-containing enzymes was studied to clarify the roles of coenzyme PQQ. Thus catalytic oxidations of amines, amino acids, glucose, alcohols, thiols, and nitroalkanes with PQQ were investigated from the stand point of organic chemistry and effective redox system was found as oxidase models.
Yoshiki Ohshiro, Shinobu Itoh
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Oxidation of D-glucose by coenzyme PQQ: 1,2-enediolates as substrates for PQQ oxidation
Journal of the Chemical Society, Chemical Communications, 1987Studies on the oxidation of D-glucose and related substrates with coenzyme PQQ have established that 1,2-enediolates are efficient substrates for PQQ oxidation.
Shinobu Itoh +2 more
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1989
A new method for gas chromatographic analysis of PQQ is presented. A sample was made weakly-alkaline and passed through a Sep-Pak C18 cartridge. The eluate was then made acid with HCl and passed through the second Sep-Pak C18 cartridge. Finally, PQQ was eluted with pyridine solution; it was evaporated to dryness.
O. Suzuki +4 more
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A new method for gas chromatographic analysis of PQQ is presented. A sample was made weakly-alkaline and passed through a Sep-Pak C18 cartridge. The eluate was then made acid with HCl and passed through the second Sep-Pak C18 cartridge. Finally, PQQ was eluted with pyridine solution; it was evaporated to dryness.
O. Suzuki +4 more
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Mutants of Methylobacterium organophilum Unable to Synthesize PQQ
Antonie van Leeuwenhoek, 1989The phenotype of mutants unable to synthesize PQQ is analyzed for different categories of methylotrophic bacteria. The advantages offered by strains dissimilating methylamine through methylated amino-acids are discussed. In M.organophilum, 40% of the mutants unable to grow in methanol medium but with normal methylamine utilization, were affected in PQQ
F, Biville +3 more
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The reaction of coenzyme PQQ with hydrazines
Journal of the Chemical Society, Perkin Transactions 2, 1990The reaction of coenzyme PQQ with hydrazines, which are known to be inhibitors of quinoprotein amine oxidases, has been investigated in vitro. Only the redox reaction is observed in the reaction with phenylhydrazine, methylhydrazine,N,N-dimethylhydrazine, and N, N′-dimethylhydrazine.
Minae Mure +4 more
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