Amidolytic Assay of Thrombin Bound to α2-Macroglobulin in Plasma

Authors :: Musumeci, V.
Landolfi, R.
Bizzi, B.
Source :: Haemostasis; January 1977, Vol. 6 Issue: 2 p98-109, 12p
Publication Year :: 1977
Abstract: A method for the determination in plasma of α<subscript>2</subscript>-macroglobulin-bound thrombin is described. α<subscript>2</subscript>-Macroglobulin-bound thrombin is precipitated from plasma by 13% polyethyleneglycol, and its amidolytic activity is assayed by using the chromogenic substrate benzoyl-Phe-Val-Arg-p-nitroanilide (S 2160). After thrombin addition to plasma, only about 1.7 % of the added thrombin activity was recovered in the α<subscript>2</subscript>-macroglobulin precipitate. It is suggested that the contribution of α<subscript>2</subscript>-macroglobulin to the antithrombin activity of normal plasma is of little relevance.