Fig. 2.

Concentration-dependent inhibition of PMPMEase by fragrances. Purified porcine liver PMPMEase (0.2 µg/µL) was preincubated at 37°C for 15 min with the indicated concentrations of each inhibitor as described in the methods section. RD-PNB substrate (0.2 mM) was then added followed by further incubation for 1 h. Reactions were stopped by the addition of methanol. These were then chilled to precipitate the proteins before centrifugation at 5000 × g for 5 min. The supernatants were then analyzed by reversed-phase HPLC for residual PMPMEase activity. The activities are expressed as percentages of the uninhibited controls (± SEM, N = 3).