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Titolo:
DIFFUSION OF PEROXYNITRITE ACROSS ERYTHROCYTE-MEMBRANES
Autore:
DENICOLA A; SOUZA JM; RADI R;
Indirizzi:
UNIV REPUBLICA,FAC MED,DEPT BIOQUIM,AVDA GRAL FLORES 2125 MONTEVIDEO 11800 URUGUAY UNIV REPUBLICA,FAC MED,DEPT BIOQUIM MONTEVIDEO 11800 URUGUAY UNIV REPUBLICA,FAC CIENCIAS,DEPT PHYS BIOCHEM MONTEVIDEO 11800 URUGUAY
Titolo Testata:
Proceedings of the National Academy of Sciences of the United Statesof America
fascicolo: 7, volume: 95, anno: 1998,
pagine: 3566 - 3571
SICI:
0027-8424(1998)95:7<3566:DOPAE>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRIC-OXIDE; SUPEROXIDE-DISMUTASE; CARBON-DIOXIDE; OXIDATION; NITRATION; TRANSPORT; KINETICS; CELLS; INHIBITION; PROTEINS;
Keywords:
NITRIC OXIDE; SUPEROXIDE; 4.4'-DIISOTHIOCYANATOSTILBENE-2,2'-DISULFONIC ACID; ANION TRANSPORT; HEMOGLOBIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
54
Recensione:
Indirizzi per estratti:
Citazione:
A. Denicola et al., "DIFFUSION OF PEROXYNITRITE ACROSS ERYTHROCYTE-MEMBRANES", Proceedings of the National Academy of Sciences of the United Statesof America, 95(7), 1998, pp. 3566-3571

Abstract

Peroxynitrite anion (ONOO-) is a reactive species of increasingly recognized biological relevance that contributes to oxidative tissue damage, At present, however, there is limited knowledge about the mechanisms of peroxynitrite diffusion through biological compartments, In thiswork we have studied the diffusion of peroxynitrite across erythrocyte membranes, In solution, peroxynitrite rapidly reacts with oxyhemoglobin to yield methemoglobin, with k(2) = (10.4 +/- 0.3) x 10(3) M-1 . s(-1) at PII 7.4 and 25 degrees C, Addition of peroxynitrite to intact erythrocytes caused oxidation of intracellular oxyhemoglobin to methemoglobin, Oxidation yields in red blood cells at pH 7.0 were approximately 40% of those obtained in solution, which results mostly from competition of other cytosolic components for peroxynitrite. Indeed, rathersmall differences were observed between oxidation yields in lysates compared with intact erythrocytes, in particular at acidic and neutral pH values, indicating that membrane was not precluding peroxynitrite diffusion, Incubation of erythrocytes at PH 7.0 with 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), a specific inhibitor of anionexchange, resulted in up to 50% inhibition of oxyhemoglobin oxidationby peroxynitrite. More protection by DIDS was achieved at alkaline pH, while no effect was observed at pH 5.5, where 95% of peroxynitrite is in the acidic form, ONOOH (pK(a) = 6.8), In addition, peroxynitrite caused nitration of intracellular hemoglobin, in a process that was enhanced in thiol-depleted erythrocytes. Our results indicate that peroxynitrite is able to cross the erythrocyte membrane by two different mechanisms: in the anionic form through the DIDS-inhibitable anion channel, and in the protonated form by passive diffusion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/09/20 alle ore 14:27:07