The functional role of CD36 protein detected in mitochondrial fractions in long chain fatty acid (LCFA) oxidation is unclear due to conflicting results obtained in Cd36 knockout mice and experiments using sulfo-N-Succinimidyl oleate (SSO) for inhibition of CD36 mediated LCFA transport: We investigated effect of SSO on mitochondrial respiration and found that SSO substantially inhibits not only LCFA oxidation, but also oxidation of flavoprotein- and NADH-dependent substrates and generation of mitochondrial membrane potential. Experiments in rat liver, heart and kidney mitochondria demonstrated a direct effect on mitochondrial respiratory chain with the most pronounced inhibition of the complex III (IC50 4 mu M SSO). The results presented here show that SSO is a potent and irreversible inhibitor of mitochondrial respiratory chain. (C) 2010 Published by Elsevier Inc.