NADH Oxidase Activity of Mitochondrial Apoptosis-inducing Factor

We report the biochemical characterization of Apoptosis-inducing factor ’s redox activity

M. Dolores Miramar; Paola Costantini; Luigi Ravagnan; Ligia M. Saraiva; Delphine Haouzi; Greg Brothers; Josef M. Penninger; M. Luisa Peleato; Guido Kroemer; Santos A. Susin


Scholarcy highlights

  • Mitochondria are considered as central players in apoptosis of mammalian cells
  • Properties of Recombinant Apoptosis-inducing factor Protein—Recombinant AIF⌬1–120 was found to elute as a single peak on a gel filtration column, with a calculated mass weight of 57 kDa, which corresponds to its theoretical molecular mass, indicating that, at near-physiological salt concentrations, AIF⌬1–120 is a monomer
  • Total thiol content was confirmed after unfolding in 8 M urea. This suggests that none of the three cysteines contained in the AIF amino acid sequence engages in disulfide links
  • The results from this work indicate that AIF has a marked NADH oxidase activity
  • According to the classification by Massey, AIF may belong to the electron-transferase class of NADH reductases, because it reacts rapidly with oxygen, forming O2Ϫ and the flavoprotein neutral radical as products
  • Since AIF is the only NADH oxidase detected in the intermembrane space, it is tempting to speculate that AIF accounts for the mitochondrial superoxide anion or hydrogen peroxide-generating NADH oxidase activity, which is lost from mitochondria, once cells have been induced to die
  • Inhibition of the apoptogenic effect of Apoptosis-inducing factor by means of para-chloromercuriphenylsulfonic acid failed to affect its NADH oxidase activity

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