Fig. 5.
Effect of HK25c on the binding of kallikrein (⊡) and 125I-kallikrein (♦) to HUVEC-bound HK. (A) After preincubation with HK, HUVEC were incubated with increasing concentrations of HK25c in the presence of 10 nmol/L kallikrein or 125I-kallikrein. The ability of HK25c to inhibit kallikrein binding to cell-bound HK was determined by measuring the residual cell-associated kallikrein activity and 125I-kallikrein by radioactivity. The IC50 of HK25c determined in this manner was 50 ± 10 nmol/L (SD) for kallikrein and 150 nmol/L for 125I-kallikrein. (B) The kd of HK25c and kallikrein averaged from three binding assay plots of HK25c is 70 ± 10 nmol/L (SD).
