Antimycin A

Background

Antimycin A is an inhibitor of electron transport from cytochrome b to cytochrome complex III (cytochrome c reductase). Binding of Antimycin A to cytochrome c reductase inhibits the oxidation of ubiquinol, disrupts the Q-cycle of enzyme turnover, and halts cellular respiration (1). Consequently, this small, non-peptide ligand inhibitor has been used for decades to characterize the mitochondrial respiratory chain (2). Antimycin A has long been used as a piscicide in commercial fish farms, and possesses strong antifungal, insecticidal, and nematocidal activities (3). Treatment of HeLa cells with Antimycin A results in the loss of mitochondrial membrane potential and inhibition of cell growth through apoptosis. Antimycin A strongly generates reactive oxygen species and induces glutathione depletion in these cells (4). Antimycin A binds and inhibits Bcl2/Bcl-xL-related anti-apoptotic proteins, which are commonly over-produced by cancer cells (5,6).