Biomaterial Database

Inactivation of microsomal NADPH-cytochrome c reductase by sulfhydryl-reactive derivatives of menadione. 1984

R E Talcott, and A Ketterman, and D G Giannini

Five derivatives of menadione (2-methyl-1,4-naphthoquinone) having electronegative substituents on allylic carbons were prepared for study as sulfhydryl-reactive inactivators of mouse liver microsomal NADPH-cytochrome c reductase. Each of these naphthoquinones, incubated with dilute suspensions of microsomes, produced a loss of NADPH-cytochrome c reductase activity proportional to the initial naphthoquinone concentration. Each of the compounds also reacted with cysteine, as evidenced in the case of the halogenated compounds, by loss of reactive sulfhydryl groups and, in the case of 2-p-nitrophenoxymenadione, by the displacement of the leaving group, p-nitrophenol. Menadione, incubated under identical conditions, did not inactivate NADPH-cytochrome c reductase and was unreactive with cysteine. The requirement for a halogen or a nitrophenoxy substituent on at least one of the allylic carbons suggested that the mechanism of NADPH-cytochrome c reductase inactivation involves attack on critical microsomal nucleophiles, possibly sulfhydryl groups. The possible significance of these findings is discussed in relation to the antitumor activity and bioactivation of the halomethyl naphthoquinones.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D009251	NADPH-Ferrihemoprotein Reductase	A flavoprotein that catalyzes the reduction of heme-thiolate-dependent monooxygenases and is part of the microsomal hydroxylating system. EC 1.6.2.4.	Cytochrome P-450 Reductase,Ferrihemoprotein P-450 Reductase,NADPH Cytochrome P-450 Oxidoreductase,NADPH Cytochrome P-450 Reductase,NADPH Cytochrome c Reductase,Cytochrome P-450 Oxidase,Cytochrome P450 Reductase,Ferrihemoprotein P450 Reductase,NADPH Cytochrome P450 Oxidoreductase,NADPH Cytochrome P450 Reductase,NADPH-Cytochrome P450 Reductase,NADPH-P450 Reductase,Cytochrome P 450 Oxidase,Cytochrome P 450 Reductase,Ferrihemoprotein P 450 Reductase,NADPH Cytochrome P 450 Oxidoreductase,NADPH Cytochrome P 450 Reductase,NADPH Ferrihemoprotein Reductase,NADPH P450 Reductase,Oxidase, Cytochrome P-450,P-450 Oxidase, Cytochrome,P450 Reductase, Cytochrome,P450 Reductase, NADPH-Cytochrome,Reductase, Cytochrome P-450,Reductase, Cytochrome P450,Reductase, Ferrihemoprotein P-450,Reductase, Ferrihemoprotein P450,Reductase, NADPH-Cytochrome P450,Reductase, NADPH-Ferrihemoprotein,Reductase, NADPH-P450
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D013439	Sulfhydryl Reagents	Chemical agents that react with SH groups. This is a chemically diverse group that is used for a variety of purposes. Among these are enzyme inhibition, enzyme reactivation or protection, and labelling.	SH-Reagents,Sulfhydryl Compound Antagonists,Sulfhydryl Compound Inhibitors,Thiol Reagents,Sulfhydryl Compounds Antagonists,Sulfhydryl Compounds Inhibitors,Antagonists, Sulfhydryl Compound,Antagonists, Sulfhydryl Compounds,Compound Antagonists, Sulfhydryl,Compound Inhibitors, Sulfhydryl,Inhibitors, Sulfhydryl Compound,Inhibitors, Sulfhydryl Compounds,Reagents, Sulfhydryl,Reagents, Thiol,SH Reagents
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.
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In