Competitive inhibition of lipolytic enzymes. I. A kinetic model applicable to water-insoluble competitive inhibitors

It is now becoming clear from the abundant lipolytic enzyme literature that any meaningful interpretation of inhibition data has to take into account the kinetics of enzyme action at the lipid/water interface. We attempt in the present paper to provide a kinetic model applicable to water-insoluble competitive inhibitors, in order to quantitatively compare the results obtained at several laboratories. We derived kinetic equations applicable to the pre-steady state as well as steady state. By measuring the inhibitory power, as described in the present paper, it is possible to obtain a normalized estimation of the relative efficiency of various potential inhibitors. Furthermore, with the kinetic treatment developed here, it is possible to make quantitative comparisons with the same inhibitor placed under various physico-chemical situations, i.e., micellar or monolayer states.