Prothrombin Derivatives in Human Serum. Isolation and Some Properties of the Non-Thrombin Fragments

Abstract

The main non-thrombin fragment of prothrombin (the ‘pro-fragment’) was isolated from human serum. Its electrophoretic mobility was influenced by calcium, and on electrophoresis the preparation separated into two equal sized fractions. The ‘pro-fragment’ was active in the prothrombin-proconvcrtin determination according to Owren. On storage it underwent further fragmentation. Tissue extract and calcium or high concentrations of sodium citrate accelerated this reaction. The new main fragment formed showed esterolytic activity against tosyl-L-arginin methylester. It is con cluded that the main physical and chemical' characteristics of factor VII and factor X of blood coagulation also apply to the non-thrombin fragments of prothrombin.

Key Words:

• Blood coagulation
• prothrombin
• thrombin