What's the difference between quinhydrone and quinone?
Quinhydrone
Definition:
(n.) A green crystalline substance formed by the union of quinone with hydroquinone, or as an intermediate product in the oxidation of hydroquinone or the reduction of quinone.
Example Sentences:
(1) The quinole oxidizes then to the quinhydrone and finally to primin itself.
(2) Its spectral characteristics, as well as the kinetic effects induced by substitution of the benzenoid part of the flavine, can hardly be taken into account by a quinhydrone-like structure for the intermediate dimers at any pH value.
(3) The redox electrodes are typified by the Quinhydrone electrode.
(4) Absorption and retention of all of these actinides was increased substantially by fasting and by the addition of mild oxidizing agents, ferric iron and quinhydrone.
(5) In contrast, fasting increased 210Pb absorption fivefold, and the oxidizing agents ferric iron and quinhydrone blocked the effect of fasting.
(6) Absorption of 233U, 238Pu, 241Am, and 244Cm from the gastrointestinal (GI) tract was measured in rats, fed ad libitum or fasted, that were gavaged with solutions containing ferric iron, ferrous iron, iron powder, quinhydrone or ascorbic acid.
(7) Both cutaneous melanin and adrenochrome appear to exist in a quinhydrone status.
Quinone
Definition:
(n.) A crystalline substance, C6H4O2 (called also benzoketone), first obtained by the oxidation of quinic acid and regarded as a double ketone; also, by extension, any one of the series of which quinone proper is the type.
Example Sentences:
(1) The thiol-conjugating capacity of quinones may, however, be applied to reduce the tissue-damaging effects of stimulated neutrophils.
(2) The effect of dicoumarol on glucuronidation of 3-OH-benzo(a)pyrene (BP) appears to be due to inhibition of UDPglucuronosyltransferase (UDPGT) and not to an inhibited DT-diaphorase (NAD(P)H:quinone oxidoreductase); to date the only enzyme known to be inhibited by dicoumarol.
(3) The coupled dienone-phenol re-arrangement and keto-enol tautomerism of this quinone methide produce the observed 3,4-dihydroxybenzaldehyde.
(4) Moreover, it seems unlikely that quinones are involved directly (e.g.
(5) The second-order rate constants appear to be at least 3 orders of magnitude lower than the second-order constants for quenching of the fluorescent probes; this is taken as a clear indication that ubiquinone diffusion is not the rate-determining step in the quinone-enzyme interaction.
(6) 15 human tumour cell lines (lung, breast and colon) have been evaluated for their sensitivity to the quinone based anti-cancer drugs Mitomycin C, Porfiromycin, and EO9 (3-hydroxymethyl-5-aziridinyl-1-methyl-2-(IH-indole-4,7-dione)prop-beta- en-alpha-ol).
(7) These studies provide evidence that GHB exerts cytotoxicity specifically for cells that by their content of tyrosinase convert the phenol to the quinone.
(8) Comparison of these two activities for both the quinone and hydroquinone showed that the hydroquinone form had superior activities.
(9) Bis(alkylthio)quinones 4a-d and 5a-d, and corresponding hydroquinones 9b-d exhibited high activities both in vitro and in vivo.
(10) It seems that quinone pigments, especially 2-oxyjuglone, react with complex I faster than it follows from their approximate values of one-electron reduction potential calculated from their reactivities with flavocychrome b2 and adrenodoxin.
(11) Formation of catechol from quinone by cyst extracts was observed spectrophotometrically and chromatographically.
(12) The present studies were conducted to evaluate the relative effect of the parent chemical BHT and two of its major oxidative metabolites, 2,6-di-tert-butyl-4-hydroxymethylphenol (BHT-BzOH) and 2,6-di-tert-butyl-1,4-benzoquinone (BHT-quinone), on DMBA-induced rat mammary tumorigenesis and on the formation of rat mammary DMBA-DNA adducts in vivo.
(13) Quinones play a major role in allergic contact dermatitis caused by plants.
(14) The urushiol analogs 5-pentadecylresorcinol (PDR) and 3-heptadecylveratrole (HDV) which cannot form o-quinones were found to be ineffective sensitizers as well.
(15) Toxicity of quinone(di)imines to hepatocytes and CHO cells was not related to superoxide anion radical formation, and toxicity to CHO cells was not affected by exclusion of oxygen during exposure of the cells to the compounds.
(16) The activity of cytochrome P-450 reductase, which reduces quinones to hydroquinones in the estrogen redox cycle, was 6-fold higher in liver than in kidney of both control and estrogen-treated animals.
(17) The interaction of pyrroloquinoline quinone (PQQ) with amino groups was followed by measuring the capacity of adducts to reduce nitroblue tetrazolium (NBT).
(18) The menadione-induced quinone reductase was isolated from the cytoplasmic fraction of induced cells.
(19) Hepa 1c1c7 murine hepatoma cells are plated in 96-well microtiter plates, grown for 24 h, and exposed to inducing agents for another 24 h. The cells are then lysed and quinone reductase activity is assayed by the addition of a reaction mixture containing an NADPH-generating system, menadione (2-methyl-1,4-naphthoquinone), and MTT [3-(4,-5-dimethylthiazo-2-yl)-2,5-diphenyltetrazolium bromide].
(20) quinone complex (X) was chemically reduced (state [PIX-]; P is the reaction center bacteriochlorophyll dimer, I is the long wavelength bacteriopheophytin), and compares these with the fluorescence observed when all the traps are open (state [PIX]) and with the fluorescence observed when all the traps are closed (state [P+IX]).