Fig. 3. Hydrolysis of PAF by Culex quinquefasciatus SGH. One pair of homogenised salivary glands was incubated with 50 µl of 100 µmol l^-1 PAF in 0.1 mol l^-1 ammonium acetate, pH 7.2. At the indicated times, 5 µl of the reaction mixture was diluted tenfold with 80 % methanol plus 0.1 % acetic acid and injected into the mass spectrometer. (A) Mass spectrum done immediately after mixing the substrate with the homogenate. (B) Mass spectrum at 120 min. (C–H) Disappearance of PAF-associated masses and appearance of indicated product masses. A control sample without salivary homogenates incubated for 2 h had an identical spectrum to A. The line on C was the best non-linear fit of a two-parameter hyperbolic decay curve. The lines on D–H were the best non-linear fit for a two-parameter hyperbolic curve.