Chromogenic substrate assay of plasma prekallikrein. With a note on its site of biosynthesis

A method for assaying plasma prekallikrein has been developed applying the chromogenic substrate Chromozym PK. Different variables have been investigated, and the final assay system was found to give a reproducible and reliable assay procedure. A normal value of 99.0 +/- 18% was found, the coefficient of variation being 7.9. Studies on material from patients with various liver diseases indicated that the main site of prekallikrein biosynthesis is the liver.