title: [Stimulation of the NADPH:adrenodoxin reductase diaphorase reaction by adrenodoxin].
abstract: The diaphorase activity of NADPH: adrenodoxin reductase (EC 1.18.1.2) is stimulated by adrenodoxin. The latter prevents the reductase inhibition by NADPH; the Line-weaver-Burk plots are characterized by a biphasic dependence of the reaction rate on the oxidizer concentration. At pH 7.0 the maximal rate of the first phase is 20s-1; that for the second phase at saturating concentrations of adrenodoxin is 5 s-1. Since the second phase rate is equal to that of the adrenodoxin-linked cytochrome c reduction by reductase it is concluded that this phase reflects the reduction of the oxidizers via reduced adrenodoxin. Quinones are reduced by adrenodoxin in an one-electron way; the logarithms of their rate constants depend hyperbolically on their single-electron reduction potentials (E7(1]. The oxidizers interact with a negatively charged domain of adrenodoxin. The depth of the adrenodoxin active center calculated from the Fe(EDTA)- reduction data is 5.9 A.
authors.forename: I A
authors.initials: IA
authors.lastname: Martsinkiavichene
authors.forename: N K
authors.initials: NK
authors.lastname: Chenas
authors.forename: Iu Iu
authors.initials: IuIu
authors.lastname: Kulis
authors.forename: S A
authors.initials: SA
authors.lastname: Usanov
mesh_terms: D000325:Adrenodoxin / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D008058:Dihydrolipoamide Dehydrogenase / Q000187:drug effects* / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D005287:Ferredoxin-NADP Reductase / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D011809:Quinones / Q000378:metabolism
chemical_list: D011809:Quinones; D000325:Adrenodoxin; D005287:Ferredoxin-NADP Reductase; D008058:Dihydrolipoamide Dehydrogenase
vernacular_title: Stimulirovanie diaforaznoĭ reaktsii NADPH:adrenodoksinreduktazy adrenodoksinom.