The Importance of Activation of Antihemophilic Globulin and Proaccelerin by Traces of Thrombin in the Generation of Intrinsic Prothrombinase Activity

Rapaport, Samuel I.; Schiffman, Sandra; Patch, Mary Jane; Ames, Sara Beth

doi:10.1182/blood.v21.2.221.221

Cited by 188 publications

(50 citation statements)

References 8 publications

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“…Trace amounts of thrombin are known to enhance the activity of factor VIII. This activation is necessary before interaction with factor IXa (Rapaport et al, 1963;Osterud et al, 1971). The initial increase in activity is followed by a subsequent decrease in activity, as measured by one-stage clotting assays (Rick and Hoyer, 1977).…”

Section: Analysis Of the Function Of R-viii Sq And R-viii R5mentioning

confidence: 99%

Novel Forms of B‐Domain‐Deleted Recombinant Factor VIII Molecules

Lind¹,

Larsson²,

Spira³

et al. 1995

European Journal of Biochemistry

122

111

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Recombinant molecules similar to the smallest active plasma-derived factor VIII molecule, a complex of an 80-kDa and a 90-kDa polypeptide chain lacking the B domain, have been produced using various factor VIII cDNA constructs in order to obtain primary translation products which were efficiently processed into the 80+90-kDa complex. Three types of single-chain cDNAs encoding B-domain-deleted derivatives factor VIII were designed, taking account of sites at Arg740 and Glu1649, assumed to be important for processing factor VIII.In the type 1 constructs, either Arg747, Arg752, or Arg776 in the N-terminal region of factor VIII B domain was fused to the N-terminus (Glu1649) of the 80-kDa subunit. In the type 2 construct r-VIII SQ, Ser743 was fused to Gln1638, creating a link of 14 amino acids between the C-terminus (Arg740) of the 90-kDa chain and N-terminus of the 80-kDa chain, whereas in type 2 r-VIII RH, Arg747 was fused to His1646. In the type 3 constructs, the B-domain was completely removed or replaced with 1-4 Arg residues.After expression in Chinese hamster ovary cells, the type 1 derivatives and the type 3 derivatives with 0-2 Arg residues inserted were found to be only partially processed and contained a large amount of the 170-kDa primary translation product. In contrast, most of the type 2 derivatives r-VIII SQ and r-VIII RH and the type 3 derivatives r-VIII R4 and r-VIII R5 containing three or four extra Arg residues preceding the N-terminus of the 80-kDa chain were processed into the desired 80+90-kDa chain complexes. The feature common to the most efficiently processed factor VIII deletion derivatives was that they contained the recognition motif for proteolytic cleavage by the membrane-bound subtilisin-like protease furin, which is expressed in most types of cells; that is, basic amino acid residues at positions -1 and -4 relative to the cleavage site at Glu1649. Biochemical studies of r-VIII SQ and r-VIII R5, two of the most effectively processed factor VIII derivatives, showed that both proteins had a normal factor VIII cofactor function, and had N-and C-termini of the 80-kDa and 90-kDa chains corresponding to those found in plasma-derived factor VIII.

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Section: Analysis Of the Function Of R-viii Sq And R-viii R5mentioning

confidence: 99%

Novel Forms of B‐Domain‐Deleted Recombinant Factor VIII Molecules

Lind¹,

Larsson²,

Spira³

et al. 1995

European Journal of Biochemistry

122

111

View full text Add to dashboard Cite

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“…It is now possible, therefore, to indicate the sequence of events from the activation of Factor XI1 to the activation of Factor X.The International Committee on the Nomenclature of Blood Clotting Factors has refrained from considering the nomenclature of derived products. Schiffman,-Rapaport and Patch (1963) have studied the activation of Factor IX (PTC) by contact product and they have used the notation PTC' for activated Factor IX and PTA' for activated Factor XI. Other terms such as Intermediate Product I (probably activated Factor X-Bergsagel and Hougie, 1956), Activated Factor IX, Factor IX Product, Accelerin (Activated Factor V), Convertin (Activated Factor VII), etc., have been used by various workers.…”

mentioning

confidence: 99%

The Interaction of Factors VIII and IX

Biggs

et al. 1964

Br J Haematol

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“…It has been known for some time that very small amounts of thrombin markedly enhance the activity of VIII:C in one-stage assays (Rapaport et al, 1963;Biggs et al, 1965). This enhancement, however, was not seen in the two-stage assays (Biggs et al, 1965;Niemetz and Nossel, 1969), which showed only a gradual loss of VIII:C activity as more thrombin was added.…”

Section: Effect Of Thrombinmentioning

confidence: 95%

Comparisons of One‐stage and Two‐stage Assays of Factor Viii:c

Barrowcliffe

1984

Scandinavian Journal of Haematology

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Comparisons of one‐stage and two‐stage methods are made in terms of technical aspects, precision and potency estimates. Because of the different dilution ranges and reagents, there is a higher concentration of clotting factors and total protein in the one‐stage essays, and a higher ratio of VIII R:Ag/VIII:C. The one‐stage assay is technically simpler and easier to automate, but the two‐stage method is probably more sensitive. In international collaborative studies, the two‐stage method has been generally more precise, but current differences in precision between the methods are small. Discrepancies between the methods occur in assays of concentrates against plasma standards, sometimes also against concentrate standards, and in assessment of in vivo recovery. The adsorption step used in the two‐stage method is a major cause of the discrepancy is assays of concentrates against plasma. Other possible causes of discrepancies between the methods in assays of concentrates are: pre‐dilution in buffer or haemophilic plasma; thrombin activation; the influence of VIII R:Ag on VIII:C activity; non‐specific contaminants such as lipids.

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The Importance of Activation of Antihemophilic Globulin and Proaccelerin by Traces of Thrombin in the Generation of Intrinsic Prothrombinase Activity

Cited by 188 publications

References 8 publications

Novel Forms of B‐Domain‐Deleted Recombinant Factor VIII Molecules

Novel Forms of B‐Domain‐Deleted Recombinant Factor VIII Molecules

The Interaction of Factors VIII and IX

Comparisons of One‐stage and Two‐stage Assays of Factor Viii:c

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