sentences:  Hydrogen cyanide is most potent as an inhibitor at pH 6, the optimum pH for the enzyme, suggesting that the rate-limiting step of catalysis is the formation of the Schiff base intermediate.Beta-diketones appear to inhibit acetoacetate decarboxylase well but slowly.Acetoacetate decarboxylase has a KM for acetoacetate of 7×10−3 M whereas the enzyme has a KI for benzoylacetone of 1.9×10−6 M. An enamine is most likely formed upon interaction of beta-diketones with free enzyme.