| Popis: |
The importance of calcium irons for the action of pro-coagulant blood clotting factors has been known since the time of Morawitz’s classical theory and the practical application of this knowledge is demonstrated in the use of anticoagulants for the collection of blood used in laboratory investigations. The necessity for cations in the interaction between the pro-coagulant factors and their inhibitors has not been described. We now find that during the isolation and purification of antithrombin from normal plasma, the use of dialysis tended to diminish or even abolish the activity of this inhibitor. However, when the dialysate was reintroduced into the dialysed plasma or fraction containing the antithrombin, the activity was restored, although the dialysate itself showed no antithrombin activity. On reintroduction of divalent cations in place of the dialysate, the activity was also restored. It seems therefore, that these divalent cations are necessary for the interaction of thrombin and antithrombin. Although the exact mechanism of action of these cations has not been completely elucidated, it would appear that they act possibly by the removal of charges or by facilitation of bonding between the two reactants. |
