A study on the properties of commercial thrombin preparations

Three commercial thrombin preparations used clinically to stop topical bleeding were studied. The specific activities of these preparations were 1,064 U/mg (human); 59 U/mg (bovine) and 147 U/mg (bovine). SDS-PAGE analysis of the human product produced one major band corresponding to a molecular weight of alpha-thrombin and one minor band. The bovine preparations produced several bands in addition to the alpha-thrombin band. One of bovine preparations had the highest amidolytic activity toward synthetic substrates S-2238 and S-2251 and also showed fibrinolytic activity when tested with the plasminogen-free fibrin plate method. Immunological analysis revealed that one preparation (human origin) contained immunoglobulin G, hepatitis B surface (HBs) antibody and human immunodeficiency virus (HIV) antibody. All of the preparations maintained more than 80% of their proteolytic activity for six hours when dissolved in physiological saline solution. It was found that the product A (bovine origin) was the best from the viewpoints of the specific activity, the stability and the purity which was free from factor Xa and plasmin.