Regulation of alternative oxidase kinetics by pyruvate and intermolecular disulfide bond redox status in soybean seedling mitochondria

FEBS Letters

Umbach, Ann L.²  Wiskich, Joseph T.¹  Siedow, James N.² 

[1] Botany Department, University of Adelaide, North Terrace, Adelaide SA, Australia;Department of Botany, Duke University, Box 90338, Durham, NC 27708-0338, USA

关键词: Cyanide-resistant oxidase;    Plant mitochondrion;    Pyruvate activation;    Dimeric enzyme;    Regulatory disulfide bond;    Diamide;    azodicarboxylic acid;    DTT;    dithiothreitol;    Qr;    reduced mitochondrial ubiquinone;    Qt;    total mitochondrial ubiquinone pool;    Qr/Qt;    proportion of the ubiquinone pool in the reduced state;    SDS-PAGE;    sodium dodecyl sulfate polyacrylamide gel electrophoresis;    SHAM;    salicylhydroxamic acid;   

DOI  :  10.1016/0014-5793(94)00600-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Two factors known to regulate plant mitochondrial cyanide-resistant alternative oxidase activity, pyruvate and the redox status of the enzyme's intermolecular disulfide bond, were shown to differently affect activity in isolated soybean seedling mitochondria. Pyruvate stimulated alternative oxidase activity at low levels of reduced ubiquinone, shifting the threshold level of ubiquinone reduction for enzyme activity to a lower value. The disulfide bond redox status determined the maximum enzyme activity obtainable in the presence of pyruvate, with the highest rates occurring when the bond was reduced. With variations in cellular pyruvate levels and in the proportion of reduced alternative oxidase protein, a wide range of enzyme activity is possible in vivo.

【 授权许可】

Unknown