Direct characterization of factor VIII in plasma: detection of a mutation altering a thrombin cleavage site (arginine-372----histidine)

Proc Natl Acad Sci U S A. 1989 Jun;86(11):4277-81. doi: 10.1073/pnas.86.11.4277.


An immunoadsorbent method has been developed for the direct analysis of normal and variant plasma factor VIII. Using this method, the molecular defect responsible for mild hemophilia A has been identified for a patient whose plasma factor VIII activity is 0.05 unit/ml, even though the factor VIII antigen content is 3.25 units/ml. Although the variant factor VIII has an apparently normal molecular mass and chain composition, the 92-kDa heavy chain accumulates when the variant protein is incubated with thrombin and the 44-kDa heavy chain fragment cannot be detected. In contrast, thrombin cleavage of the 80-kDa light chain to the 72-kDa fragment is normal. As these data indicate a loss of factor VIII cleavage by thrombin at arginine-372, the genetic defect was determined by polymerase-chain-reaction amplification of exon 8 of the factor VIII gene and direct sequencing of the amplified product. A single-base substitution (guanine----adenine) was identified that produces an arginine to histidine substitution at amino acid residue 372. These data identify the molecular basis of an abnormal factor VIII, "factor VIII-Kumamoto," that lacks procoagulant function because of impaired thrombin activation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Arginine*
  • Base Sequence
  • Factor VIII / analysis*
  • Factor VIII / genetics
  • Factor VIII / isolation & purification
  • Genes
  • Hemophilia A / blood*
  • Hemophilia A / genetics
  • Histidine*
  • Humans
  • Immunoblotting
  • Molecular Sequence Data
  • Mutation*
  • Thrombin / metabolism


  • Histidine
  • Factor VIII
  • Arginine
  • Thrombin