Preferential inhibition of the plasma membrane NADH oxidase (NOX) activity by diphenyleneiodonium chloride with NADPH as donor.
The cell-surface NADH oxidase (NOX) protein of plant and animal cells will utilize both NADH and NADPH as reduced electron donors for activity. The two activities are distinguished by a differential inhibition by the redox inhibitor diphenyleneiodonium chloride (DPI). Using both plasma membranes and cells, activity with NADPH as donor was markedly inhibited by DPI at submicromolar concentrations, whereas with NADH as donor, DPI was much less effective or had no effect on the activity. The possibility of the inhibition being the result of two different enzymes was eliminated by the use of a recombinant NOX protein. The findings support the concept that NOX proteins serve as terminal oxidases for plasma membrane electron transport involving cytosolic reduced pyridine nucleotides as the natural electron donors and with molecular oxygen as the electron acceptor.
Morré
D James
DJ
Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-1333, USA. morre@pharmacy.purdue.edu
D002462:Cell Membrane / Q000201:enzymology*; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004583:Electrons; D006367:HeLa Cells; D006801:Humans; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors*; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors*; D009249:NADP / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology*; D011725:Pyridines / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
D009097:Multienzyme Complexes; D009861:Onium Compounds; D011725:Pyridines; D011994:Recombinant Proteins; D009249:NADP; C007517:diphenyleneiodonium; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases