The lipase forms an addition compound with the ester as well as with the cleavage products. The speed of the reaction is not the same for all esters; and, for any substrate, is only approximately proportional to the time. After an initial steep drop or slight increase, the velocity decreased to the end of the reaction. This decrease is not due to progressive decomposition of several enzymes but to their combining with the products of cleavage[long dash]on the alkaline side with the alcohol, and on the acid side with both alcohol and acid. Since the binding velocity of the alcohol-enzyme is less than that of ester-enzyme, the amount of inhibition depends as much on enzyme concentration as on temp. The more slowly the reaction proceeds, the more pronounced is the inhibition. The form of the reaction curve, therefore, depends not only on the affinity of the lipase for the ester and its cleavage products, but also on the velocity at which saponification proceeds, which in turn depends upon temp. and enzyme concentration.