Inhibition of Enzymic ( Thrombokinase ) Activation of Blood Clotting by Organic Phosphates (ATP,ADP,AMP),Involving a Calcium Complex. ∗

Summary

Reduction of thrombin yields in an enzymic (thrombokinase)-activated 2-stage clotting system is achieved in vitro by mM additions of organic phosphates (ATP, ADP, AMP). This is investigated in relation to pH and Ca⁺⁺ concentration, optima for which are defined in control systems. The evidence indicates that the major inhibition must be related to some unknown calcium complex, which is a yield-determining factor in thrombin generation, even without the organic phosphates. ATP-ase degrades ATP and largely removes its inhibitory action.