A phospholipase C activity specific for platelet-activating factor (PAF), named PAF phosphorylcholine hydrolase, was found in the salivary glands and saliva of the human-feeding mosquito Culex quinquefasciatus. The enzymatic activity was demonstrated by inhibition of PAF-induced platelet aggregation, and by identification of substrate consumption and production of diacyl glyceride by electrospray-ionisation mass spectrometry. The activity has a neutral optimal pH and an apparent molecular mass of 40-50 kDa. Two anthropophilic mosquito species, Aedes aegypti and Anopheles gambiae, do not have this salivary activity. The results are interpreted within the evolutionary context of the genera Culex, Aedes and Anopheles. VSports手机版.