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Titolo:
Regulation of inducible nitric oxide synthase by self-generated NO
Autore:
Abu-Soud, HM; Ichimori, K; Nakazawa, H; Stuehr, DJ;
Indirizzi:
Cleveland Clin, Lerner Res Inst, Dept Immunol, Cleveland, OH 44195 USA Cleveland Clin Cleveland OH USA 44195 pt Immunol, Cleveland, OH 44195 USA Cleveland Clin, Lerner Res Inst, Dept Cell Biol, Cleveland, OH 44195 USA Cleveland Clin Cleveland OH USA 44195 Cell Biol, Cleveland, OH 44195 USA Tokai Univ, Dept Physiol, Isehara, Kanagawa 2591193, Japan Tokai Univ Isehara Kanagawa Japan 2591193 sehara, Kanagawa 2591193, Japan
Titolo Testata:
BIOCHEMISTRY
fascicolo: 23, volume: 40, anno: 2001,
pagine: 6876 - 6881
SICI:
0006-2960(20010612)40:23<6876:ROINOS>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
L-ARGININE; ELECTRON-TRANSFER; HEME; OXYGEN; INHIBITION; SUBSTRATE; BINDING; DOMAIN; TETRAHYDROBIOPTERIN; CALMODULIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Abu-Soud, HM Cleveland Clin, Lerner Res Inst, Dept Immunol, 9500 Euclid Ave, Cleveland,OH 44195 USA Cleveland Clin 9500 Euclid Ave Cleveland OH USA 44195 195 USA
Citazione:
H.M. Abu-Soud et al., "Regulation of inducible nitric oxide synthase by self-generated NO", BIOCHEM, 40(23), 2001, pp. 6876-6881

Abstract

A ferric heme-nitric oxide (NO) complex can build up in mouse inducible nitric oxide synthase (iNOS) during NO synthesis from L-arginine. We investigated its formation kinetics, effect on catalytic activity, dependence on solution NO concentration, and effect on enzyme oxygen response (apparent KmO(2)). Heme-NO complex formation was biphasic and was linked kinetically to an inhibition of electron flux and catalysis in iNOS. Experiments that utilized a superoxide generating system to scavenge NO showed that the magnitude of heme-NO complex formation directly depended on the NO concentration achieved in the reaction solution. However, a minor portion of heme-NO complex (20%) still formed during NO synthesis even when solution NO was completely scavenged. Formation of the intrinsic heme-NO complex, and the heme-NO complex related to buildup of solution NO, increased the apparent KmO2 of iNOS by 10- and 4-fold, respectively. Together, the data show heme-NO complexbuildup in iNOS is due to both intrinsic NO binding and to equilibrium binding of solution NO, with the latter predominating when NO reaches high nanomolar to low micromolar concentrations. This behavior distinguishes iNOS from the other NOS isoforms and indicates a more complex regulation is possible for its activity and oxygen response in biologic settings.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/03/20 alle ore 05:14:01