FIGURE 6.

Reactivity profiles of furin variable loop mutants with synthetic substrate and serpin inhibitors. Bar graphs depicting the effects of mutating the four variable surface loops of furin to alanines on k_cat/K_m for furin cleavage of a tetrapeptide fluorogenic substrate and on k_a for furin reactions with serpin B8-5S, α₁PDX, and α₁PDX-serpin B8 P6–P1, P1′–P5′, and P6–P5′ chimeras. k_cat/K_m values are taken from Table 2 and k_a values are from Table 3. Numbers at the top of bars represent kinetic constants expressed relative to wild-type furin values.