Purification of urokinase by affinity chromatography.

Commercially available urokinase (EC 3.4.99.26), though highly active, is still contaminated with unrelated proteins and degradation fragments of urokinase. Further purification of a urokinase preparation by chromatography on benzamidine-Sepharose is described. The final preparation consisted of two molecular forms of urokinase with molecular weights of respectively 31 000 and 54 000. The 54 000-dalton urokinase appears to be composed of two protein chains, one of which is the 31 000-dalton urokinase. A monospecific antiserum against urokinase was raised.