Interaction of alpha-cyano[14C]cinnamate with the mitochondrial pyruvate translocator.

The binding of alpha-cyanocinnamate to rat-heart mitochondrial membrane was investigated using alpha-cyano[14C]cinnamate. The binding was correlated to the inhibition of pyruvate transport. The results obtained demonstrate that both these functions reach saturation at the same titre of the inhibitor. Quantitative parameters of alpha-cyano[14C]cinnamate binding have been determined. The binding can be prevented by pyruvate and other substrates of the carrier but not by acetate. Pyruvate decreases the affinity of alpha-cyanocinnamate binding, leaving the maximum number of binding unchanged. It is concluded that rat-heart mitochondria contain a specific site at which alpha-cyanocinnamate binds which is directly involved in the inhibition of pyruvate transport.