[Structural model of factor VIII complex].

Gel filtration patterns on Sepharose CL-2B of functional subunits (procoagulant, ristocetin cofactor, antigen) derived from highly purified human factor VIII indicate that the native, intact complex is reproducibly eluted in the void volume. The complex is, however, degraded by proteolytic (and possibly other) enzymes contaminating the purified material during dialysis at room temperature. Resulting degradation products were fractionated by gel filtration and characterized by SDS-polyacrylamide electrophoresis. Our results suggest that factor VIII consists of identical subunits (mol. wt. about 500 000) which might be linked together by hydrophobic bonds. Only native high molecular weight aggregates posses ristocetin cofactor activity.