[Use of N-benzoyl-phenylalanyl-valyl-arginine p-nitroanilide and hirudin for the detection of enzymatic activity under prothrombin acylation by citraconic anhydride].

Acylation of bovine prothrombin by cytraconic anhydride results in the formation of the thrombin active site, which provides the degradation of highly specific thrombin substrate, N-bensoyl-Phe-Val-Arg p-nitroanilide. This reaction is inhibited with hirudin, highly specific thrombin inhibitor.