2.5. Enzyme Inhibition Kinetics

Lineweaver–Burk analysis was used to identify the kinetic parameters and inhibition modes for the enzymatic reactions of curcumin, demethoxycurcumin, and bisdemethoxycurcumin against pancreatic lipase [20]. Briefly, the effects of p-nitrophenyl butyrate at different concentrations on the initial velocity (v) of different inhibitor concentrations was determined at a fixed concentration of pancreatic lipase (5 mg/mL) with reference to the above enzyme-activity assay method. The maximum catalytic reaction rate (V_max), Michaelis constant (K_m), and inhibition constant (K_i) were determined within the double-reciprocal plot with the following equations:

The [S] represents concentrations of substrate, and [I] means inhibitor.