Fig. 4.
Effect of cholesterol on the trimera dependence NADPH oxidase activity. The assays mixtures consisted of trimera at varying concentrations (from 0 to 420 nM) and membrane fractions of human neutrophils (3 nM Cyt b558) to which were added ● 40 µM AA or ■ a mixture of 40 µM AA and 10 µM cholesterol. The superoxide formation was measured as indicated in Materials and methods. Each curve was fitted by Michaelis–Menten like equation leading to the determination of the EC50 and Vmax values related to the trimera. The values of these kinetic parameters in the presence of AA alone or AA plus cholesterol are in Table 2. The values are an average of three independent measurements±SEM.