Clotting Factor X. Physiologic and Physico-Chemical Properties

Summary

1. A new clotting factor, factor X, participating in blood thromboplastin formation is demonstrated by matching experiments with various pathological sera. The possible influence of thrombin and factor VII is eliminated. The objection that factor X deficiency may be nothing else than a slight deficiency of factor IX is discussed. This hypothesis is in contradiction with our results. 2. Factor X is present in normal serum and in hemophilia B-Serum. absent in hepatitisserum and in serum of Marcoumar-(Dicoumarol derivative) treated patients. The affinity of factor X to barium sulfate is greater than that of Factor VII and IX. This property is utilised for the purification of Factor X. 3. Factor X is not identical with PTA and the new factors of Spaet et al. and of Ratnoff et al.