FIGURE 3.

Time course of PIP₂ hydrolysis by hPLCγ1 (A), hPLCβ2 (B), and hPLCδ1 (C) in cholate-mixed micelles in the presence and absence of U73122 (10 μm). Purified PLC isozymes were incubated with U73122 in the presence of 0.03 mm cholate for 10 min at 32 °C prior to the addition of cholate-solubilized micelles containing 50 μm PIP₂. Data represent mean ± S.E. and are representative of two or more separate experiments. D, relative fold increase in rate caused by incubation with 10 μm U73122 for the four PLC isozymes evaluated in mixed micellar systems.