Effect of oxygen on activation state of complex I and lack of oxaloacetate inhibition of complex II in Langendorff perfused rat heart

FEBS Letters

Cecchini, Gary²  Maklashina, Elena²  Kotlyar, Alexander B²  Karliner, Joel S¹ 

[1] Cardiology Section, VA Medical Center, San Francisco, CA 94121, USA;Molecular Biology Division, VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA

关键词: NADH:ubiquinone oxidoreductase;    Complex I;    Active/de-active transition;    Succinate dehydrogenase;    Complex II;    Krebs cycle;    regulation;    Oxygen;    Mitochondrion;    BTP;    bis-Tris–propane;    Complex I;    NADH:ubiquinone oxidoreductase;    Complex II;    succinate:ubiquinone oxidoreductase;    SMP;    submitochondrial particles;    OAA;    oxaloacetate;    SDH;    succinate dehydrogenase;    A-form;    active form;    D-form;    de-active form;    PES;    phenazine ethosulfate;   

DOI  :  10.1016/S0014-5793(03)01369-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Two main entry points for electrons into the mitochondrial respiratory chain are NADH:ubiquinone oxidoreductase (complex I) and succinate:ubiquinone oxidoreductase (complex II). Metabolic regulation of these two respiratory complexes is not understood in detail. It has been suggested that the Krebs cycle metabolic intermediate oxaloacetate (OAA) inhibits complex II in vivo, whereas complex I undergoes a reversible active/de-active transition. In normoxic and anoxic hearts it has been shown that the proportion of complex I in the active and de-active states is different suggesting a possible mode of regulation of the enzyme by oxygen concentration. In the current studies rapid isolation of mitochondrial membranes in a state that preserves the activity of both complex I and complex II has been achieved using Langendorff perfused rat hearts. The findings indicate that the state of activation of complex I is controlled by the oxygen saturation in the perfusate. In addition, these studies show that complex II is fully active in the mitochondrion and not inhibited by OAA regardless of the oxygen concentration.

【 授权许可】

Unknown