Fig. 7.

SIC interferes with HK binding to endothelial cells. Biotin–HK (20 nM) was added to endothelial cells (HUVEC) in HEPES-Tyrode's buffer containing 50 μM Zn²⁺ in the presence of protein SIC (•, 1–200 μM), CM–papain (▿, 1–30 μM) or cystatin C (○, 1–100 μM). The proportion of biotin–HK bound to HUVECs was determined in the presence of each competitor protein after non-specific binding was subtracted. Non-specific binding was determined by the level of binding seen in the presence of a 50-fold molar excess of unlabelled HK. Data presented are the mean±sem of three experiments. The absence of error bars at some data points indicates a small deviation of values.