In vitro assay for prekallikrein activator (PKA).

The assay measures the action of prekallikrein in generating kallikrein. The prekallikrein activator is the limiting reagent. The product kallikrein is an esterase which can be quantitated using benzoyl arginine ethyl ester. The assay is reproducible and results are comparable with other methods. The large scale preparation of prekallikrein is described.