Figure 7.

Influence of other proteins on biotin–HK binding to cytokeratin. Biotin–HK (20 nM) in the absence (NO COMPETITOR) or presence of 1 μM of LK, factor XII (XII), soluble uPAR, or gC1qR fusion protein was incubated in 0.01 M sodium phosphate and 0.15 M NaCl (pH 7.4) containing 1% BSA, 0.01% Tween 20, and 50 μM Zn²⁺ in microtiter plate wells that were coated with 1 μg/well cytokeratin. Nonspecific binding (No Zn²⁺) was determined by biotin–HK binding in the absence of added Zn²⁺. The amount of biotin–HK bound to the microtiter plate wells was determined as indicated in Experimental Procedures. The data presented are the mean ± SEM of three experiments.