(C) To determine the contribution of ATP demand to increased energy expenditure under UK5099 cells were permeabilized and cytosolic ADP concentrations were clamped. OCR were measured in the presence of 5 mM pyruvate, 3 mM malate, 0.1 mM palmitoyl-CoA, 0.5 mM carnitine and 5 mM ADP. Cells were treated with either 100 nM, 1 µM or 10 µM UK5099. Data shows maximal state 3 OCR normalized to maximal complex 4 activity from n=3 individual experiments. 