Purification of urokinase by a beta-naphthamidine affinity column

Urokinase was purified by affinity chromatography using 6-amino-naththamidine-(2), a new specific ligand based on the urokinase inhibitor beta-naphthamidine. Urokinase was firmly bound at pH 7.0 and could be eluted at pH 3.0. The protein which passed the column at pH 7.0 without being bound did not contain any urokinase activity. This is an important property because it can be utilized for raising a monospecific urokinase antiserum by absorbing unspecific antibodies with only a minor loss of antiserum titre.