Inactivation of Factor Va by APC single-point mutants.

FVa was incubated at a concentration of 1 nmol/L with 50 pmol/L wild-type or mutant APC and inactivation was followed over time as described in “Materials and methods.” (A) APC: wild-type (+), 306A (▵), 307A (○), 308A (◊), 309A (□). (B) APC: wild-type (+), 311A (▵), 312A (○), 314A (◊). Data points shown are averages of between 3 to 6 experiments for each APC. Standard deviations for all the data points shown averaged ± 3.4%. Error bars are shown for wild-type APC in panel B for illustrative purposes. Other error bars are left out because many of the curves are so close to each other. Curves were fit to the equation in “Materials and methods” according to Nicolaes and colleagues.l11 Coefficient of determination (r²) values were 0.995 or greater for all the curves except for that of 314A-APC (0.977).