Biomaterial Database

Formation of glutathione-conjugated semiquinones by the reaction of quinones with glutathione: an ESR study. 1987

N Takahashi, and J Schreiber, and V Fischer, and R P Mason

The nonenzymatic reaction of the cytotoxic compounds menadione (2-methyl-1,4-naphthoquinone) and 1,4-naphthoquinone (a reactive metabolite of 1-naphthol) with reducing agents such as NADPH and glutathione led to the formation of semiquinone-free radicals, which were detected with electron spin resonance spectroscopy. In the presence of glutathione as a reducing agent, menadione and 1,4-naphthoquinone underwent net one-electron reduction and conjugation with glutathione. At higher concentrations of glutathione, 1,4-naphthoquinone formed the semiquinones of both the monoconjugate and the diconjugate. The naphthoquinone-glutathione conjugates should redox cycle in a manner already known for the menadione conjugate. The semiquinone intermediates could be detected only under a nitrogen atmosphere and are probably the primary oxygen-reactive species responsible for the redox cycling of menadione- and naphthoquinone-glutathione conjugates.

UI	MeSH Term	Description	Entries
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D009285	Naphthoquinones	Naphthalene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.	Naphthalenediones,Naphthazarins,Naphthoquinone
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D011809	Quinones	Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
D004578	Electron Spin Resonance Spectroscopy	A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D014812	Vitamin K	A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K.
D016227	Benzoquinones	Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.	1,2-Benzoquinones,1,4-Benzoquinones,Benzodiones,2,5-Cyclohexadiene-1,4-Diones,o-Benzoquinones,p-Benzoquinones