Summary
Commercial thrombin was shown to contain appreciable amounts of thrombokinase. Passage through a DEAE-cellulose column substantially reduced the thrombokinase titer, although significant contamination could still be detected. Similarly, repeated barium sulfate adsorptions failed to remove the thrombokinase completely.
However, barium sulfate adsorptions followed by passage through a column of DEAE-cellulose resulted in an essentially complete removal of the contaminant. Thrombin, so obtained, did not accelerate activation of prothrombin in the presence of calcium, phosphatide and barium carbonate adsorbed serum.
Thrombokinase, separated by chromatography, was able to activate prothrombin very slowly in the presence of oxalate. Comparably dilute thrombin fractions and the unfractionated commercial preparation either did not possess this capability, or else this capability was obscured by a concomitant loss of thrombin.
