Purified BDD-FVIII proteins. BDD-FVIII H1/H2, H3/H5, and H4 proteins analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis plus Coomassie brilliant blue staining showed high purity and the expected molecular weights. Molecular weights of protein standards are indicated in kDa. Refacto (Pfizer) was run as a BDD-FVIII standard. Lane 1: Refacto (10 μL, 300 IU/mL). Lane 2: Refacto (10 μL, 100 IU/mL). Lanes 3, 4, 5, 6: BDD-FVIII-H3/H5 (∼0.2 μg), BDD-FVIII-H1/H2 (0.56 μg), BDD-FVIII-H3/H5 (0.37 μg), and BDD-FVIII-H4 (0.46 μg), respectively, purified from representative clones, 1 μL/lane.