The NADPH:quinone oxidoreductase P1-zeta-crystallin in Arabidopsis catalyzes the alpha,beta-hydrogenation of 2-alkenals: detoxication of the lipid peroxide-derived reactive aldehydes.
Plant Cell Physiol
; 43(12): 1445-55, 2002 Dec.
Article
em En
| MEDLINE
| ID: mdl-12514241
ABSTRACT
P1-zeta-crystallin (P1-ZCr) is an oxidative stress-induced NADPHquinone oxidoreductase in Arabidopsis thaliana, but its physiological electron acceptors have not been identified. We found that recombinant P1-ZCr catalyzed the reduction of 2-alkenals of carbon chain C(3)-C(9) with NADPH. Among these 2-alkenals, the highest specificity was observed for 4-hydroxy-(2E)-nonenal (HNE), one of the major toxic products generated from lipid peroxides. (3Z)-Hexenal and aldehydes without alpha,beta-unsaturated bonds did not serve as electron acceptors. In the 2-alkenal molecules, P1-ZCr catalyzed the hydrogenation of alpha,beta-unsaturated bonds, but not the reduction of the aldehyde moiety, to produce saturated aldehydes, as determined by gas chromatography/mass spectrometry. We propose the enzyme name NADPH2-alkenal alpha,beta-hydrogenase (ALH). A major portion of the NADPH-dependent HNE-reducing activity in A. thaliana leaves was inhibited by the specific antiserum against P1-ZCr, indicating that the endogenous P1-ZCr protein has ALH activity. Because expression of the P1-ZCr gene in A. thaliana is induced by oxidative stress treatments, we conclude that P1-ZCr functions as a defense against oxidative stress by scavenging the highly toxic, lipid peroxide-derived alpha,beta-unsaturated aldehydes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
NAD(P)H Desidrogenase (Quinona)
/
Arabidopsis
/
Zeta-Cristalinas
/
Alcenos
Idioma:
En
Revista:
Plant Cell Physiol
Assunto da revista:
BOTANICA
Ano de publicação:
2002
Tipo de documento:
Article