[Formation of the prothrombin-phosphatidyl serine and thrombin-phosphatidyl serine complex].

A possibility of formation of the thrombin-phosphatidyl serine and prothrombin-phosphatidyl serine complex is discussed. Prothrombin incubation with 131J-labelled phosphatidyl serine and its subsequent activation results in a formation of a thrombin-phosphatidyl serine--131J-complex. The radioactive label is also detected in the protein precipitate after thermodenaturation of thrombin preincubated with 131J-labelled phosphatidyl serine, which suggests that thrombin is firmly bound to phosphatidyl serine. The formation of the thrombin-phosphatidyl serine and prothrombin-phosphatidyl serine complex is supported by data of gel-filtration on Sephadex G-200 and acrylexes P-150 and P-60, as well as by differential spectrophotometry.