Role of Plasma Accelerator-Globulin and Serum Accelerator-Globulin in Conversion of Prothrombin

¹ From the Biochemistry Department, U. S. Army Medical Research Laboratory, Fort Knox, Kentucky

Either plasma accelerator-globulin or serum accelerator-globulin must be present in order to obtain complete conversion of prothrombin in the presence of serum-eluate factor(s) [proconvertin or plasma thromboplastin component or both], antihemophilic factor, platelet factor 3, and calcium ions. If plasma accelerator-globulin is present, it must first be converted to serum accelerator-globulin by the action of thrombin before the maximum rate of prothrombin conversion is reached. Serum accelerator-globulin does neither affect the degree nor the rate of interaction of serum-eluate factor(s), antihemophilic factor, platelet factor 3, and calcium ions forming a prothrombin-conversion factor but affects thrombin formation at a point just prior to or during the conversion of prothrombin.