APC-cofactor activity of protein S Heerlen in FVa- and FVIIIa-degradation assays.

(A) FVa-degradation assay. APC-mediated inactivation of wild-type FVa (solid lines) or FVa Leiden (dotted lines) was measured in the presence of wild-type protein S or protein S Heerlen. The mean of 2 independent experiments performed in duplicate are shown. (B) FVIIIa-degradation assay. Inactivation of FVIIIa was performed in either the absence or presence of FV, together with increasing concentrations of wild-type protein S or protein S Heerlen. The means ± SEM of 3 independent experiments performed in duplicate are shown.