title: Inhibition of the redox cycling of vitamin K3 (menadione) in mouse liver microsomes.
abstract: 1. Concentration-dependent effects of vitamin K1, coenzyme Q10, butylated hydroxytoluene, nor-dihydroguaiaretic acid and Fe-initiated lipid peroxidation on redox cycling of vitamin K3 were studied in mouse liver microsomes in vitro. 2. The antioxidants (butylated hydroxytoluene, nor-dihydroguaiaretic acid) caused apparent non-competitive inhibition of vitamin K3 redox cycling. 3. Vitamin K1 and coenzyme Q10 caused competitive inhibition of the redox cycling (Ki = 33 and 46 microM, respectively). 4. Fe-initiated microsomal lipid peroxidation caused irreversible decrease of one-electron reduction of vitamin K3. 5. The role of NADPH:cytochrome P-450 reductase along with mechanisms of these inhibitions are discussed.
authors.affiliation: Grace Cancer Drug Center, Roswell Park Memorial Institute, New York State Department of Health, Buffalo 14263.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Byczkowski
authors.forename: T
authors.initials: T
authors.lastname: Gessner
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D003067:Coenzymes; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D008054:Lipid Peroxides / Q000096:biosynthesis; D009637:Masoprocol / Q000494:pharmacology; D051379:Mice; D008811:Mice, Inbred DBA; D008862:Microsomes, Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects; D011809:Quinones / Q000494:pharmacology; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000494:pharmacology; D014812:Vitamin K / Q000378:metabolism*; D010837:Vitamin K 1 / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D003067:Coenzymes; D008054:Lipid Peroxides; D011809:Quinones; D014812:Vitamin K; D014451:Ubiquinone; D002084:Butylated Hydroxytoluene; D009637:Masoprocol; D010837:Vitamin K 1; D007501:Iron; C024989:coenzyme Q10