OUTSTANDING CHARACTERISTICS OF THROMBOKINASE ISOLATED FROM BOVINE PLASMA.
Thrombokinase has been isolated from bovine plasma by a procedure which begins with the highly purified product of a previously described method, chromatographs it on DEAE-cellulose, and then fractionates it by continuous flow electrophoresis, yielding 0.2 mg per liter of oxalated plasma. The electrophoretic fraction has shown a single boundary in the ultracentrifuge; and its esterase activity on toluenesulfonylarginine methyl ester has been about the same as that of thrombokinase previously isolated by repeated electrophoretic fractionations. Thrombokinase is a euglobulin with minimum solubility near pH 5.0. It is most stable within the pH range 7.5 to 9.5; but there is also a peak in the stability curve near pH 1.8. A few micrograms of thrombokinase per milliliter can activate prothrombin in the presence of EDTA. A few thousandths of a microgram causes rapid production of thrombin in the system: prothrombin, thrombokinase, calcium chloride, phosphatide, "accelerator." But, thrombokinase has less than 1/175 the proteolytic activity of crystallized trypsin.
D000818:Animals; D002364:Caseins; D002417:Cattle; D002498:Centrifugation; D055598:Chemical Phenomena; D002621:Chemistry; D002845:Chromatography; D004492:Edetic Acid; D004586:Electrophoresis; D004950:Esterases; D015951:Factor Xa; D006863:Hydrogen-Ion Concentration; D011516:Prothrombin; D012106:Research; D013925:Thromboplastin; D014357:Trypsin
D002364:Caseins; D011516:Prothrombin; D013925:Thromboplastin; D004492:Edetic Acid; D004950:Esterases; D014357:Trypsin; D015951:Factor Xa
CASEIN; CATTLE; CENTRIFUGATION; CHEMISTRY; CHROMATOGRAPHY; EDTA; ELECTROPHORESIS; ESTERASES; EXPERIMENTAL LAB STUDY; HYDROGEN-ION CONCENTRATION; THROMBOPLASTIN; TRYPSIN