Peptide Bond Cleavages and Loss of Functional Activity during Inactivation of Factor Va and Factor Va by Activated Protein C

Factor V was purified from the plasma of an activated protein C (APC)-resistant patient who is homozygous for the mutation Arg Gln (factor V ). Factor V was converted by thrombin into factor Va which was further purified yielding a factor Va preparation that had the same cofactor activity in prothrombin activation as normal factor Va. Inactivation of low concentrations of normal factor Va (