Pyrrolo-quinoline quinone

C. Anthony, M. Ghosh, and C.C. Blake, The structure and function of methanol dehydrogenase and related quinoproteins containing pyrrolo-quinoline quinone. Biochem. J. 304, 665-674 (1994). 

PYRROLO-QUINOLINE QUINONE (PQQ) THE PROSTHETIC GROUP OF METHANOL DEHYDROGENASE... 

The light-induced control of the electroactivity of charged redox-active substrates allows the functionalized electrode to be used to control electrochemical transformations. A system composed of two oppositely charged diffusional redox probes—positively charged 2,5-bis[[2-(dimethylbutylammo-nio)ethyl]amino]-l,4-benzoquinone (14) and negatively charged pyrrolo-quinoline quinone (PQQ) (15)—was used to demonstrate this behavior... 

Methoxantin coenzyme (PQQ, pyrrolo quinoline quinone, 2,7,9-tricarboxy-lff-pyrrolo-[2,3- /]-quinoline-4,5-dione, 4,5-dihydro-4,5-dioxo-lfl-pyrrolo[2,3 quinoline-2,7,9-tri-carboxylic acid) [72909-34-3] M... 

Quinone containing redox enzymes are a much less widely studied group, and to date fewer examples have been characterized. The prosthetic group in this case is a quinone, pyrrolo-quinoline quinone (PQQ), and again it is a two-electron... 

The electrochemistry of the PQQ (pyrrolo-quinoline quinone) prosthetic group has been investigated at poly(pyrrole)-coated electrodes, and PQQ has been entrapped within poly(pyrrole) films " good electrochemistry was observed in both cases. Poly(pyrrole) has also been used to entrap adenosine triphosphate (ATP) anions, again by growing the film in the presence of the anion, " and as an electrode material for oxidizing ascorbate. " In the latter case the oxidation... 

Pyrrolo quinoline quinone, PQQ 2,7,9-tricar-boxy-li/-pyrrolo [2,3-/ quinoline-4,5-dione, the cofactor of methanol dehydrogenase (EC 1.1.99.8) from Hyphomicrobium X and Melhylophilus methy-lotrophus, and of glucose dehydrogenase (EC 1.1.99.17) from Acinebacter cakoaceticus. [J. A. Duine et al. Eur. J.Biochem. 108 (1980) 187-192]... 

Besides the permselective properties, the electrocatalytic properties of ECP films can be also used for the amperometric detection of some target molecules. Accordingly, electrodes modified with PPy, polythiophene (PTh), PAni, and their derivatives were found to catalyze the electrochemical oxidation of ascorbic acid [127-129], NADH [115, 116,130], dopamine [128], pyrrolo-quinoline quinone [131] as a coenzyme of some oxidoreductases, and quinone and derivatives [132, 133]. Selectivity exhibited by these materials could be enhanced by the introduction of an appropriate substituent onto the polymer backbone. So, a facilitated electron transfer between cytochrome c and carboxylic acid or carboxylate-substituted PPy [134] or polyindole [135] has been observed. As such an effect was not obtained with unsubstituted polymer films, the cytochrome c-polymer interaction was e lained on the basis of binding between the polymer substituents and the lysine residues on the redox protein. 

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