[Non-linear, non-competitive inhibition of lactate dehydrogenase with carboxylic acid anions (substrate analogues)].

The carboxylic acid anions are shown to inhibit lactate dehydrogenase in a non-competitive manner at pH 8.5. The inhibitory effect of different carboxylates used increases in the direction acetate leads to formate leads to methacrylate. Non-competitive inhibition by carboxylates has a non-linear character with effective Hill exponent depending on the inhibitor concentration increasing to the value n approximately equal to 2 when inhibitor concentration increases. The kinetic model is proposed to account for non-linear non-competitive inhibition in consequence of the abortive ternary complexes formation in two enzyme conformations. The substrate analogues properties that result in non-competitive inhibition of lactatedehydrogenase are considered.