Electron transfer between a quinohemoprotein alcohol dehydrogenase and an electrode via a redox polymer network

A quinohemoprotein alcohol dehydrogenase (QH-EDH) from Comamonas testosteroni was immobilized on an electrode in a redox polymer network consisting of a polyvinylpyridine partially N-complexed with osmiumbis-(bipyridine)chloride. The enzyme effectively transfers electrons to the electrode via the polymer. An average maximum catalytic current of...

Inter-individual variability in the oxidation of 1,2-dibromoethane: Use of heterologously expressed human cytochrome P450 and human liver microsomes

1,2-Dibromoethane (1,2-DBE) is mainly used as an additive in leaded gasoline and as a soil fumigant and it is a suspected carcinogen in humans. In this study, the oxidative bioactivation of 1,2-DBE to 2-bromoacetaldehyde (2-BA) was studied using heterologously expressed human cytochrome P450 (P450) isoenzymes and human liver microsomes. Out of...

The biotransformation of isoprene and the two isoprene monoepoxides by human cytochrome P450 enzymes, compared to mouse and rat liver microsomes

The metabolism of isoprene was investigated with microsomes derived from cell lines expressing human CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, or CYP3A4. The formation of epoxide metabolites was determined by gas chromatographic analysis. CYP2E1 showed the highest rates of formation of the isoprene monoepoxides 3,4-epoxy-3-methyl-1...

Autoantibodies against MDA-LDL in subjects with severe and minor atherosclerosis and healthy population controls

Autoantibodies against oxidized low-density lipoprotein (LDL) have been reported to be associated with atherosclerosis. However, data are not consistent. We compared the titres of autoantibodies to malondialdehyde-modified LDL in three groups, a case group with angiographically documented severe coronary stenosis (> 80% stenosis in at least 1...

Lipoprotein lipase stimulates the binding and uptake of moderately oxidized low-density lipoprotein by J774 macrophages

Lipoprotein lipase (LPL) stimulates the uptake of low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) in different cell types, including macrophages, through bridging of LPL between lipoproteins and extracellular heparan sulphate proteoglycans (HSPG). Because macrophages produce LPL and because modified lipoproteins are present...

Supplementation with low doses of vitamin E protects LDL from lipid peroxidation in men and women

There is accumulating evidence that oxidative modification of LDL is an important step in the process of atherogenesis and that antioxidants may protect LDL from oxidation. We and others have previously shown that ingestion of pharmacological doses of the antioxidant D,L-α-tocopherol (vitamin E), far above the recommended daily intake (ie, 12 to...

Human cytochrome P450 enzyme selectivities in the oxidation of chlorinated benzenes

1,2-Dichlorobenzene 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3,5-tetrachlorobenzene, and pentachlorobenzene were incubated with microsomes derived from cell lines expressing human CYP1A1, CYP1A2, CYP3A4, CYP2E1, or CYP2D6. The formation of phenolic metabolites as determined by gas chromatographic analysis evealed that CYP2E1 possessed...

Enhanced susceptibility of low-density lipoproteins to oxidation in coronary bypass patients with progression of atherosclerosis

Oxidation of low-density lipoprotein (LDL) may play a causal role in atherosclerosis. In this study we analyzed whether the severity of progression of coronary atherosclerosis is related to the susceptibility of LDL to oxidative modification. On the basis of repeated coronary angiography, 28 coronary bypass patients were divided into two groups:...

Reduction of oxidative DNA-damage in humans by Brussels sprouts

The effect of consumption of Brussels sprouts on levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in human urine was investigated in 10 healthy, male, non-smoking volunteers. Following a 3 week run-in period, five volunteers continued on a diet free of cruciferous vegetables for a subsequent 3 week intervention period (control group),...

No influence of beta carotene on oxidative DNA damage in male smokers

Cytochrome P450-mediated oxidation of pentafluorophenol to tetrafluorobenzoquinone as the primary reaction product

In the present study the oxidative dehalogenation of a para-halogenated phenol was studied using pentafluorophenol and its non-para-halogenated analogue 2,3,5,6-tetrafluorophenol as model compounds. 19F NMR was used to characterize the metabolite patterns. In order to study the primary oxidation products of the microsomal cytochrome P450...

The relation between the oxidative biotransformation of hexachlorobenzene and its porphyrinogenic activity

The relation between the major toxic effect of hexachlorobenzene, hepatic porphyria, and its oxidative biotransformation was studied in vivo, by observing the effect of modulating its biotransformation on the expression of porphyria. This modulation was achieved by selective in vivo inhibition of the major cytochrome P450 isoenzyme involved in...

Methanol dehydrogenase: Mechanism of action

Chemicals/CAS: alcohol dehydrogenase, 9031-72-5; alcohol dehydrogenase (acceptor), EC 1.1.99.8; Alcohol Oxidoreductases, EC 1.1; Alcohols

Fluorimetric determination of menadione sodium bisulphite (vitamin K3) in animal feed and premixes by high-performance liquid chromatography with post-column derivatization

Chemicals/CAS: menadione sodium bisulfite, 130-37-0; menadione, 58-27-5; 2-methyl-1,4-dihydronaphthalene, 2717-43-3; Naphthalenes; Vitamin K 3, 58-27-5; Vitamin K, 12001-79-5.

Induction of cytochrome formation and stimulation of oxidative dissimilation by hemin in Streptococcus lactis and Leuconostoc mesenteroides

Aerobic glucose dissimilation of washed cells of Streptococcus lactis grown in peptone-glucose-yeast extract medium is characterized by the formation of large amounts of lactic acid, a small amount of acetic acid, and traces of acetoin: a corresponding amount of oxygen is taken up. Aerobic metabolism by washed cells of S. lactis and Leuconostoc...