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Dissociation of the factor‐VIII complex during clotting: role of thrombin and phospholipids
Author(s) -
MUNTEAN W.,
ROTHWANGL H. J.
Publication year - 1984
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1984.tb01214.x
Subject(s) - chemistry , thrombin , dissociation (chemistry) , agarose , clotting factor , elution , thromboplastin , factor x , chromatography , prothrombinase , coagulation , medicine , platelet , organic chemistry
. To study the dissociation of the two moieties of the factor‐VIII complex during clotting, plasma, concentrate and serum were chromatographed on 4% agarose. In plasma and concentrate factor‐VIII coagulant activity (VIII C), factor‐VIII coagulant antigen (VIII C:Ag), and factor‐VIII‐related antigen (VIII R:Ag) eluted together in the void volume, but some VIII C: Ag eluted after the void volume. The amount of VIII C:Ag eluting after the void volume was made smaller by adding proteinase inhibitors. In serum nearly all VIII C:Ag eluted after the void volume. From factor‐VIII complex immunoadsorbed by means of an antibody against VIII R:Ag no VIII C:Ag was dissociated by thrombin or by thrombin and physiologic CaCl 2 concentrations. Radiolabelled human thrombin did not bind to the VIII C:Ag of immunoadsorbed factor‐VIII complex. VIII C:Ag displaying VIII C was dissociated from immunoadsorbed factor‐VIII complex by human brain thromboplastin or by phosphatidyl‐serine. Our results suggest that VIII C:Ag and VIII R:Ag dissociate during clotting. This dissociation seems not to be mediated by thrombin, but may be mediated by phospholipids.