RABBIT FACTOR-VIII - IDENTIFICATION OF SIZE HETEROGENEITY

  • 1 January 1977
    • journal article
    • research article
    • Vol. 49  (2) , 209-217
Abstract
Two forms of rabbit factor VIII procoagulant activity, distinguishable by size on gel filtration and ultracentrifugation, were identified in normal rabbit plasma. These studies were carried out with citrate-anticoagulated rabbit plasma obtained by cardiac puncture. Two peaks of factor VIII activity were obtained on agarose gel chromatography, using physiologic ionic strength buffers: a high molecular weight peak eluting at the void volume and a 2nd peak eluting with smaller plasma proteins. The presence of high and low molecular weight factor VIII activities was confirmed by sucrose density gradient centrifugation. The 2 peaks of factor VIII activity remained distinct when proteolytic inhibitors were added to the plasma and eluting buffers. Both the high and low molecular weight factor VIII procoagulant activities were inhibited by antibodies to human and rabbit factor VIII, and both were activated thrombin. The identification of size heterogeneity of factor VIII in normal rabbit plasma, in the absence of any modification by ionic strength, may permit more satisfactory study of the relationship of factor VIII size to function.