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Wyszukujesz frazę "nitroaromatic compounds" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Reduction of nitroaromatic compounds by NAD(P)H:quinone oxidoreductase (NQO1): the role of electron-accepting potency and structural parameters in the substrate specificity
Autorzy:
Misevičienė, Lina
Anusevičius, Žilvinas
Šarlauskas, Jonas
Čėnas, Narimantas
Powiązania:
https://bibliotekanauki.pl/articles/1041217.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
reduction potential
DT-diaphorase
nitroaromatic compounds
reduction mechanism
explosives
Opis:
We aimed to elucidate the role of electronic and structural parameters of nitroaromatic compounds in their two-electron reduction by NAD(P)H:quinone oxidoreductase (NQO1, DT-diaphorase, EC 1.6.99.2). The multiparameter regression analysis shows that the reactivity of nitroaromatic compounds (n = 38) increases with an increase in their single-electron reduction potential and the torsion angle between nitrogroup(s) and the aromatic ring. The binding efficiency of nitroaromatics in the active center of NQO1 exerted a less evident role in their reactivity. The reduction of nitroaromatics is characterized by more positive entropies of activation than the reduction of quinones. This points to a less efficient electronic coupling of nitroaromatics with the reduced isoalloxazine ring of FAD, and may explain their lower reactivity as compared to quinones. Another important but poorly understood factor enhancing the reactivity of nitroaromatics is their ability to bind at the dicumarol/quinone binding site in the active center of NQO1.
Źródło:
Acta Biochimica Polonica; 2006, 53, 3; 569-576
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single-electron reduction of quinone and nitroaromatic xenobiotics by recombinant rat neuronal nitric oxide synthase
Autorzy:
Anusevičius, Žilvinas
Nivinskas, Henrikas
Šarlauskas, Jonas
Sari, Marie-Agnes
Boucher, Jean-Luc
Čėnas, Narimantas
Powiązania:
https://bibliotekanauki.pl/articles/1039577.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
antitumour agents
nitroaromatic compounds
electron transfer mechanism
oxidative stress
quinones
Neuronal nitric oxide synthase (nNOS)
Opis:
We examined the kinetics of single-electron reduction of a large number of structurally diverse quinones and nitroaromatic compounds, including a number of antitumour and antiparasitic drugs, and nitroaromatic explosives by recombinant rat neuronal nitric oxide synthase (nNOS, EC 1.14.13.39), aiming to characterize the role of nNOS in the oxidative stress-type cytotoxicity of the above compounds. The steady-state second-order rate constants (kcat/Km) of reduction of the quinones and nitroaromatics varied from 102 M-1s-1 to 106 M-1s-1, and increased with an increase in their single-electron reduction potentials (E17). The presence of Ca2+/calmodulin enhanced the reactivity of nNOS. These reactions were consistent with an 'outer sphere' electron-transfer mechanism, considering the FMNH./FMNH2 couple of nNOS as the most reactive reduced enzyme form. An analysis of the reactions of nNOS within the 'outer sphere' electron-transfer mechanism gave the approximate values of the distance of electron transfer, 0.39-0.47 nm, which are consistent with the crystal structure of the reductase domain of nNOS. On the other hand, at low oxygen concentrations ([O2] = 40-50 μM), nNOS performs a net two-electron reduction of quinones and nitroaromatics. This implies that NOS may in part be responsible for the bioreductive alkylation by two-electron reduced forms of antitumour aziridinyl-substituted quinones under a modest hypoxia.
Źródło:
Acta Biochimica Polonica; 2013, 60, 2; 217-222
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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