Determination of the specific activity of recombinant hirudin.

The anticipated importance of recombinant hirudin as an anti-thrombotic agent necessitates the development of tools for the quantification of its biological activity. A reproducible method for the determination of the specific activity of hirudin using a sensitive chromogenic assay is described. Purified recombinant hirudin proved to be close to 100% active versus thrombin. The method can also be used to determine the thrombin concentration if the hirudin concentration is known.