title: Amidolytic assay of thrombin bound to alpha2-macroglobulin in plasma.
abstract: A method for the determination in plasma of alpha2-macroglogulin-bound thrombin is described. Alpha2-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 alpha2-macro-globulin precipitate. It is suggested that the contribution of alpha2-macroglobulin to anti-thrombin activity of normal plasma is of little relevance.
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism*; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D004590:Electrophoresis, Paper; D006801:Humans; D011092:Polyethylene Glycols / Q000494:pharmacology; D013917:Thrombin / Q000032:analysis / Q000378:metabolism*; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D000814:Aniline Compounds; D000511:alpha-Macroglobulins; D011092:Polyethylene Glycols; D013917:Thrombin