Western blotting showing APC-catalyzed cleavage of wtFV in the FVIIIa degradation assay, in the presence of either 4.4 nmol/L or 100 nmol/L protein S. Aliquots were drawn from the FVIIIa degradation experiment of Fig 4 and analyzed by Western blotting using an antibody reacting with the amino acid sequence carboxy-terminal of the Arg-306 cleavage site. The aliquot containing 100 nmol/L protein S and 0.020 nmol/L APC was badly transferred during the Western blotting.