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Titolo:
Glyceraldehyde-3-phosphate dehydrogenase inactivation by peroxynitrite
Autore:
Souza, JM; Radi, R;
Indirizzi:
Univ Republ, Fac Med, Dept Biochem, Montevideo 11800, Uruguay Univ RepublMontevideo Uruguay 11800 Biochem, Montevideo 11800, Uruguay
Titolo Testata:
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
fascicolo: 2, volume: 360, anno: 1998,
pagine: 187 - 194
SICI:
0003-9861(199812)360:2<187:GDIBP>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRIC-OXIDE; COVALENT MODIFICATION; SUPEROXIDE-DISMUTASE; S-NITROSYLATION; NAD LINKAGE; OXIDATION; MECHANISMS; NITRATION; KINETICS; PATHWAYS;
Keywords:
glyceraldehyde-3-phosphate dehydrogenase; peroxynitrite; nitric oxide; superoxide; free radicals; sulfhydryl oxidation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Radi, R Univ800,ubl, Fac Med, Dept Biochem, Avenida Gral Flores 2125, Montevideo 11 Univ Republ Avenida Gral Flores 2125 Montevideo Uruguay 11800 11
Citazione:
J.M. Souza e R. Radi, "Glyceraldehyde-3-phosphate dehydrogenase inactivation by peroxynitrite", ARCH BIOCH, 360(2), 1998, pp. 187-194

Abstract

Rabbit muscle glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was inactivated by peroxynitrite under biologically relevant conditions. The decrease of enzymatic activity followed an exponential function, and the concentration of peroxynitrite needed to inactivate 50% of 7 mu M GAPDH (IC50) was 17 mu M. Hydroxyl radical scavengers did not protect GAPDH from inactivation, but molecules that react directly with peroxynitrite such as cysteine, glutathione, or methionine and the substrate, glyceraldehyde 3-phosphate, afforded significant protection. Assuming simple competition kinetics between scavengers and the enzyme, we estimated a second-order rate constant of (2.5 /- 0.5) x 10(5) M-1 s(-1) at 25 degrees C and pH 7.4 for the GAPDH tetramer. The loss of enzyme activity was accompanied by protein thiol oxidation (two thiols oxidized per subunit) with only one critical thiol responsible of enzyme inactivation. Indeed, the pH profile of inactivation was consistent with the reaction of GAPDH sulfhydryls (GAPDH-SH) with peroxynitrite. Peroxynitrite-inactivated GAPDH was resistant to arsenite reduction and only 15% recovered by 20 mM dithiothreitol, suggesting that GAPDH-SH has been mainly oxidized to sulfinic or sulfonic acid, with a minor proportion yieldinga disulfide. On the other hand, under anaerobic conditions the peroxynitrite precursor, nitric oxide ((NO)-N-.), only slowly inactivated GAPDH with arate constant of 11 M-1 s(-1). The remarkable reactivity of the critical thiol group in GAPDH (Cys-149) toward peroxynitrite, which is one order of magnitude higher than that of previously studied sulfhydryls, indicate that it may constitute a preferential intracellular target for peroxynitrite. (C) 1998 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 19:57:27