Pushes protons across the mitochondrial membrane to help defuse free oxygen radicals. We need oxygen but it is very damaging if not controlled. Note how complex the molecule is with its two 'domains'.:-http://www.the-scientist.com//?articles.view/articleNo/41867/title/Mitochondrial-Enzyme-Detailed/-My usual comment. Tell me how Darwinian evolution did this. How much information is required to create it?