Thromb Haemost 1978; 40(01): 144-151
DOI: 10.1055/s-0038-1648644
Original Article
Schattauer GmbH Stuttgart

The Action of Immobilized Thrombin on Factor VIII, Fibrinogen and a Synthetic Tripeptide

Authors

  • J E Brown

    The Department of Pathology, University of California San Diego, School of Medicine, La Jolla, California 92093, U.S.A.
  • C L Carton

    The Department of Pathology, University of California San Diego, School of Medicine, La Jolla, California 92093, U.S.A.
  • A S Dietz

    The Department of Pathology, University of California San Diego, School of Medicine, La Jolla, California 92093, U.S.A.
  • R F Baugh

    The Department of Pathology, University of California San Diego, School of Medicine, La Jolla, California 92093, U.S.A.
  • C Hougie

    The Department of Pathology, University of California San Diego, School of Medicine, La Jolla, California 92093, U.S.A.
Further Information

Publication History

Received 20 July 1977

Accepted 14 February 1978

Publication Date:
12 July 2018 (online)

Preview

Summary

Bovine thrombin was insolubilized by attachment to cyanogen bromide-activated Sepharose (Sepharose-thrombin) or to activated (Affi-Gel 10) agarose containing a 10 Å long arm (Affi-Gel-thrombin). Coupling in both instances approximated 7,000 units of thrombin per ml packed gel as determined by 125I-thrombin incorporation. The thrombin beads hydrolyzed the synthetic tripeptide Bz-Phe-Val-Arg-pNA (S-2160) at different rates, with the Sepharose-thrombin more active (220 esterase units per ml) than Affi-Gel thrombin (20.4 units per ml). The Km was significantly higher for the insolubilized thrombins (2×10-3M) than uncoupled thrombin (Km = 8×10-5M). The Sepharose- thrombin activated factor VIII significantly more rapidly than Affi-Gel-thrombin. Neither matrix-bound thrombin clotted a fibrinogen solution or liberated significant amounts of fibrinopeptides over 48 hr. This data indicates that a proteolysis of factor VIII, rather than a complex with thrombin, is the method of activation of factor VIII and that factor VIII is more accessible to the action of immobilized thrombin than is fibrinogen.