Purification and characterization of guinea pig antithrombin III.

Antithrombin III (AT III) is a serine esterase inhibitor which regulates the activity of a number of coagulation factors. In this report, a three-step procedure for the purification of guinea pig AT III is described. This method, which involves affinity chromatography with heparin-Sepharose, ion exchange chromatography using DEAE-Sepharose, and Sephadex G-100 gel chromatography, results in purified, functionally active AT III with a 39% yield. The potential role of this molecule in the regulation of lymphocyte activation is discussed.