Figure 6
Protease inhibition assay. (a) Progress curve of the reaction of wild-type rC1-INH (dashed line) and Arg378Cys mutant (solid line) with kallikrein. (b) Plot of kobs of C1-INH wild-type (open circle) and Arg378Cys (closed circle) versus [I]0 for kallikrein (c) and C1s. rC1-INH, substrate and protease were combined in a 2-ml cuvette and substrate conversion was recorded at 405 nm. Reagent concentrations are shown in supplementary Table I. Experiments were performed at 25 °C in 50 mM Tris, 10 mM Na2HPO4, 150 mM NaCl, 0.1% Tween pH 8.
