The Modification of Xa-ATIII-Heparin Dynamics by Protamine Sulfate

Figure 5

The effect of protamine sulfate upon the FXa/ATIII/H interrelationship. Lane 1: MWM. Lane 2: PS(5 μ)15′, at R.T. Lane 3: H(1 μg)15′, at R.T. Lane 4: FXa(1.5 μg)15′, at R.T. Lane 5: ATIII(1.5 μg)]15′, at R.T. Lane 6: FXa(1.5 μg) + ATIII(1.5 μg)15′, at R.T. Lane 7: [FXa(1.5 μg)+ATIII(1.5 μg)+PS(5 μg)]15′, at R.T. Lane 8: [FXa(1.5 μg)+ ATIII(1.5 μg)+H(1 μg)]15′, at R.T. Lane 9: [FXa(1.5 μg)+ ATIII(1.5 μg)+H(1 μg)+PS(5 μg)]15′, at R.T. Protamine (lane 7) accelerates the transformation of the 1° FXa-ATIII complexes into 3° FXa-ATIII complexes, with the concomitant generation of FXaγ. Heparin (lane 8) stimulates formation of the 1° FXa-ATIII complexes and their conversion to the 3° FXa-ATIII complexes with FXaγ production. The mixture of heparin and protamine (lane 9) indicates that considerable 3° FXa-ATIII complexes are formed, but that little 1° FXa-ATIII complexes are seen (primarily as a consequence of the sequestering of heparin by protamine).