Bongkrekic Acid is a natural toxin first isolated from coconut tempeh contaminated with bacteria. It is a polyunsaturated long-chain fatty acid derivative that acts as a potent inhibitor of the mitochondrial adenine nucleotide (ADP/ATP) translocase (Ki < 2 nM). Despite its high affinity, bongkrekic acid has a slow rate of action in intact preparations, as it must permeate the inner mitochondrial membrane to bind the translocase.