2(3)-tert-Butyl-4-hydroxyanisole (BHA) is one of several widely used antioxidant food additives that protect against chemical carcinogenesis and toxicity. The present report concerns the enhancement of dicoumarol-inhibited NAD(P)H:quinone reductase [NAD(P)H dehydrogenase (quinone); NAD(P)H:(quinone acceptor) oxidoreductase, EC 1.6.99.2] activity in mouse tissues in response to dietary administr...

Ubiquinone forms an integral part of the electron transport chain in cellular respiration and photosynthesis across a vast number of organisms. Prior experimental results have shown that the photosynthetic reaction center (RC) from Rhodobacter sphaeroides is only fully functional with a limited set of methoxy-bearing quinones, suggesting that specific interactions with this substituent are requ...

The mobilities of 24 potential metabolites of benzo[a]pyrene were examined with high pressure liquid chromatography. Twelve phenols, five quinones, four dihydrodiols, and three oxides were studied. The chromatographic procedure employed allowed the separation and quantitation of benzopyrene metabolites into three major groups consisting of phenols, quinones, and dihydrodiols. Two of the benzopy...

Endogenous estrogens can be bio-activated to endogenous carcinogens via formation of estrogen quinones. Estrogen-3,4-quinones react with DNA to form mutagenic depurinating estrogen-DNA adducts. The carcinogenicity of endogenous estrogens is related to unbalanced estrogen metabolism leading to excess estrogen quinones and formation of depurinating DNA adducts. The present studies were initiated ...

With the use of an alkaliphilic bacterium, Corynebacterium humireducens MFC-5, this study investigated the reduction of goethite (α-FeOOH) and degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) mediated by different humic substances (humics) and quinones in alkaline conditions (pH of 9.0). The results indicated that (i) using sucrose as the electron donor, the strain MFC-5 was capable of red...

The enteron Escherichia coli is equipped with a branched electron transfer chain that mediates chemiosmotic electron transfer, that drives ATP synthesis. The components of this electron transfer chain couple the oxidation of available electron donors from cellular metabolism (e.g., NADH, succinate, lactate, formate, etc.) to the reduction of electron acceptors like oxygen, nitrate, fumarate, di...

o-Quinones are physiological oxidation products of catecholamines that contribute to redox cycling, toxicity and apoptosis, i.e. the neurodegenerative processes underlying Parkinson's disease and schizophrenia. The present study shows that the cyclized o-quinones aminochrome, dopachrome, adrenochrome and noradrenochrome, derived from dopamine, dopa, adrenaline and noradrenaline respectively, ar...

Oxidative stress appears to be directly involved in the pathogenesis of several neurodegenerative disorders, including Alzheimer and Parkinson diseases. Nigral dopaminergic neurons are particularly exposed to oxidative stress because a pathological accumulation of cytosolic dopamine gives rise to various toxic molecules, including free radicals and reactive quinones. These latter species can re...

The effect of quinone herbicides and fungicides on photosynthetic reactions in isolated spinach (Spinacia oleracea) chloroplasts was investigated. 2,3-Dichloro-1,4-naphthoquinone (dichlone), 2-amino-3-chloro-1,4-naphthoquinone (06K-quinone), and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) inhibited ferricyanide reduction as well as ATP formation. Benzoquinone had little or no effect on the...

The brown-rot basidiomycete Gloeophyllum trabeum uses a quinone redox cycle to generate extracellular Fenton reagent, a key component of the biodegradative system expressed by this highly destructive wood decay fungus. The hitherto uncharacterized quinone reductase that drives this cycle is a potential target for inhibitors of wood decay. We have identified the major quinone reductase expressed...