Characterization of VDAC1 as a plasma membrane NADH-oxidoreductase.
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.
Baker
Mark A
MA
ARC Centre of Excellence in Biotechnology and Development, Reproductive Science Group, School of Environmental and Life Science, University of Newcastle, NSW, Australia.
Ly
Jennifer D
JD
Lawen
Alfons
A
D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D002522:Chlorocebus aethiops; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D018272:Porins / Q000378:metabolism*; D014162:Transfection; D050995:Voltage-Dependent Anion Channel 1; D050994:Voltage-Dependent Anion Channels
D009097:Multienzyme Complexes; D018272:Porins; C494762:VDAC1 protein, human; D050994:Voltage-Dependent Anion Channels; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D050995:Voltage-Dependent Anion Channel 1; D009245:NADH Dehydrogenase