Characterization of VDAC1 as a plasma membrane NADH-oxidoreductase

Issue title: The Proceedings of the 3rd International Conference on Food Factors (ICoFF 03)

Article type: Research Article

Authors: Baker, Mark A. | Ly, Jennifer D. | Lawen, Alfons

Affiliations: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, P.O. Box 13D, 100 Wellington Road, Melbourne, Victoria 3800, Australia | ARC Centre of Excellence in Biotechnology and Development, Reproductive Science Group, School of Environmental and Life Science, University of Newcastle, NSW, Australia

Note: [] Corresponding author. Tel.: +61 3 9905 3711; Fax: +61 3 9905 3726; E-mail: Alfons.Lawen@monash.edu.au

Abstract: We have recently demonstrated that voltage dependent anion selective channel~1 (porin, isoform 1) can function as a transplasma membrane NADH:ferricyanide-reductase. However, both the specific redox characteristics and the mechanism of electron transport in this enzyme presently remain unclear. Here we demonstrate that the redox capability of porin 1 is specific for ferricyanide as this same enzyme cannot reduce DCIP or cytochrome c in vitro. Furthermore, NADH-dependent ferricyanide reduction associated with VDAC1 is not sensitive to the anion channel inhibitors DIDS and dextran sulfate. However, this activity can be inhibited by thiol chelators, suggesting that at least one of the two cysteine groups present in VDAC1 are critical for electron transfer. We propose a model on how electron transport may occur in VDAC1.

Keywords: transplasma membrane electron transport, NADH, VDAC1, ferricyanide reductase

Journal: BioFactors, vol. 21, no. 1-4, pp. 215-221, 2004