A cell-permeable α-cyanocinnamate compound that acts as a rapid, active site thiol modifying, time-dependent and non-competitive inhibitor of bi-directional pyruvate transport across plasma membranes in yeast, bacteria, Drosophila, and humans (IC50 = 50nM in rat heart mitochondria; Ki ≤ 1μM) with excellent selectivity over monocarboxylates and anions.