| Abstract: | Phospholipase A2 and C activity was quantitated using liposomes impregnated with alkaline phosphatase. Release of alkaline phosphatase was dependent on phospholipase related hydrolysis of intact vesicles. Released alkaline phosphatase was quantitated after addition of its chromogenic substrate p-nitrophenyl phosphate. The lower limit of detectability for phospholipase A2 and C activity was 0.5 unit/ml. These limits were 10-fold lower than a titrimetric method. Liposome destruction as measured by alkaline phosphatase release was calcium dependent and inhibited by 1 mM EDTA and 1 mM ZnSO4. The assay was technically simple, generated same day results, and used automated enzyme-linked immunosorbent assay instrumentation. |
