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Titolo:
Inhibition of the neutrophil NADPH oxidase and associated H+ channel by diethyl pyrocarbonate (DEPC), a histidine-modifying agent: evidence for at least two target sites
Autore:
Mankelow, TJ; Henderson, LM;
Indirizzi:
Univ Bristol, Sch Med Sci, Dept Biochem, Bristol BS8 1TD, Avon, England Univ Bristol Bristol Avon England BS8 1TD Bristol BS8 1TD, Avon, England
Titolo Testata:
BIOCHEMICAL JOURNAL
, volume: 358, anno: 2001,
parte:, 2
pagine: 315 - 324
SICI:
0264-6021(20010901)358:<315:IOTNNO>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDROGEN-ION CURRENTS; SUPEROXIDE-GENERATING SYSTEM; CYTOPLASMIC PH REGULATION; INTRACELLULAR PH; CYTOCHROME-B; RESPIRATORY BURST; PLASMA-MEMBRANE; NA+/H+ EXCHANGE; BINDING SUBUNIT; ARACHIDONATE;
Keywords:
proton channel; superoxide; therapeutic;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Henderson, LM Univ Bristol, Sch Med Sci, Dept Biochem, Univ Walk, Bristol BS8 1TD, Avon,England Univ Bristol Univ Walk Bristol Avon England BS8 1TD ,England
Citazione:
T.J. Mankelow e L.M. Henderson, "Inhibition of the neutrophil NADPH oxidase and associated H+ channel by diethyl pyrocarbonate (DEPC), a histidine-modifying agent: evidence for at least two target sites", BIOCHEM J, 358, 2001, pp. 315-324

Abstract

Diethyl pyrocarbonate (DEPC), a histidine-modifying reagent, has been utilized to demonstrate the importance of histidine residues in the functioningof proteins. In previous studies of the NADPH oxidase, histidine residues have been determined to be important in the ability of gp91(phox) to function as an H+ pathway and in the binding of haem and FAD. We have investigated the ability of DEPC to inhibit H+ flux and superoxide generation by humanneutrophils. Proton flux through the NADPH oxidase-associated H+ channel was inhibited by DEPC only if applied simultaneously with an activator of the channel. This suggested that the site modified by DEPC is not accessible in the closed channel. Superoxide generation by the NADPH oxidase was also inhibited by DEPC when applied after or simultaneously with the activator. Translocation of the NADPH oxidase cytosolic components, p67(phox) and p47(phox), to the membrane was unaffected by DEPC. In a cell-free system, DEPC-treated membranes failed to support superoxide generation or the reduction of Iodonitrotetrazolium Violet and showed a loss of the characteristic cytochrome b(558) spectrum. Superoxide generation by DEPC-treated cytosol was inhibited slightly. Therefore it can be concluded that there are two sites within the NADPH oxidase that interact with DEPC, one in the H+ pathway, only accessible in the activated oxidase, and a second accessible prior to activation of the NADPH oxidase. The latter non-proton pathway DEPC site is located within the membrane components of the NADPH oxidase and is associatedwith the binding of haem in the enzyme complex.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/03/20 alle ore 14:37:32