Thrombin inhibitory activity of fused and unfused hirudins. (A) Results of amidolytic assays of thrombin activity to which conditioned media containing 1.0 nmol/L Cos-derived recombinant protein (ALH, HLA, or HV3) was added. Conditioned media from nontransfected cells served as a negative control for inhibition (CON), while commercial HV1 was diluted in this media to 1.0 nmol/L (HV1). (B) Thrombin clotting times in the presence of 0.5 nmol/L Cos-derived recombinant protein, equivalent amounts of control conditioned media (CON), or of control conditioned media combined with HV1 (HV1). Error bars correspond to the standard deviation (n = 4) in both panels.