Figure 6 rAceAP1 inhibits factor Xa by a novel mechanism -- Factor Xa mediated cleavage of chromogenic substrate (500 pM total enzyme; 125 mM substrate) was measured in the presence of increasing amounts of the purified inhibitors. (a) Direct plot of rate data for rAcAP5; the solid curve represent best least-squares fit to equation [3]. (b) Direct plot for rAceAP1; the solid and dashed curves represents the best least-squares fit to equation [4] and [3], respectively. (c), (d) Transformed diagnostic plots corresponding to panels (a) and (b). For a simple competitive inhibition mechanism, the diagnostic plot is expected to be strictly linear.