Flavoenzymes may reduce quinones in a single-electron, mixed single- and two-electron, and two-electron way. The mechanisms of two-electron reduction of quinones are insufficiently understood. To get an insight into the role of flavin semiquinone stability in the regulation of single- vs. two-electron reduction of quinones, we studied the reactions of wild type Anabaena ferredoxin:NADP(+)reduct...

Biobased: The filamentous fungus can be used as an environmentally and sustainable benign source to produce the bio-based quinone phoenicin. This natural compound shows electrochemical properties, which active material in negative electrolyte a redox flow battery with results showing that biologically produced quinones may become real competitor currently available synthetic quinones.

Bacterial respiratory quinones in environmental samples are proposed as sensitive indicators of the aerobic versus anaerobic metabolism of bacterial populations. A liquid chromatographic method for the analysis of respiratory quinones is presented, and the proportions of ubiquinone, menaquinone and desmethylmenaquinone in aerobic and anaerobic enrichments and several environmental samples are r...

Bacterial reaction centers (RCs) catalyze a series of electron-transfer reactions reducing a neutral quinone to a bound, anionic semiquinone. The dissociation constants and association rates of 13 tailless neutral and anionic benzo- and naphthoquinones for the Q(A) site were measured and compared. The K(d) values for these quinones range from 0.08 to 90 microM. For the eight neutral quinones, i...

Previously we have shown that ONIOM type (QM/MM) calculations can be used to simulate isotope edited FTIR difference spectra for neutral ubiquinone in the QA binding site in Rhodobacter sphaeroides photosynthetic reaction centers. Here we considerably extend upon this previous work by calculating isotope edited FTIR difference spectra for reaction centers with a variety of unlabeled and (18)O l...

Oxygenic photosynthesis is the complex process that occurs in plants or algae by which the energy from the sun is converted into an electrochemical potential that drives the assimilation of carbon dioxide and the synthesis of carbohydrates. Quinones belong to a family of species commonly found in key processes of the Living, like photosynthesis or respiration, in which they act as electron tran...

Quinones are a class of compounds which have widespread importance in chemistry, biology and medicine. Because of their appropriate performance in electron transferring rate, quinones are among the most applicable mediators in biosensors. Recently, the effects of different non-metal substitutions on redox potential of quinone have been investigated to design suitable mediators for different ele...

The iron-catalyzed direct arylation of a variety N-heteroarenes, quinones, and hydroquinones with arylboronic acids is investigated under microwave heating. reaction proceeds at 70 °C air using K 2 S O 8 as an oxidant FeSO 4 catalyst. Under heating, times decreased 14- to 115-fold. Reaction scope N-heteroarenes quinones comparable or slightly expanded when compared previous reports, but the aci...

BACKGROUND Quinones are compounds extensively used in studies of oxidative stress due to their role in plants as chemicals for defense. These compounds are of great interest for pharmacologists and scientists, in general, because several cancer chemotherapeutic agents contain the quinone nucleus. However, due to differences in structures and diverse pharmacological effects, the exact toxicity m...