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ISRN Cell Biology
Volume 2012 (2012), Article ID 632867, 11 pages
Research Article

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

1Departments of Biological Sciences and Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA
2Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA

Received 27 September 2011; Accepted 10 November 2011

Academic Editor: N. Zambrano

Copyright © 2012 Martin H. Coggin and Arthur S. Brecher. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Heparin promotes the formation of 1 FXaα-ATIII and FXaβ-ATIII complexes from the free enzymes and antithrombin III. It further stimulates the transformations of the 1 complexes into the corresponding 3 complexes. Additionally, it stimulates the degradation of the 1 FXaα-ATIII and FXaβ-ATIII complexes into free FXaα, FXaβ and ATIIIM. Protamine sulfate (PS) stimulates the transformation of FXaα into FXaβ and hence to FXaγ. It also stimulates the transformation of the 1-, 2-, and 3- FXα-ATIII complexes into their corresponding β-complexes. It further promotes the degradation of the 1 FXaα- and FXaβ-ATIII complexes into their corresponding 3- FXaα- and FXaβ-ATIII complexes, with the concommittant release of FXaγ. The addition of PS to FXa/ATIII/H mixtures results in a reduction in free FXa, ATIII, and 1 Xa-ATIII complex formation, together with the concommittant increase in 3-FXa- ATIII complex formation and release of FXaγ. The likeliest explanation of these results resides in the removal of the effective free heparin as a consequence of the generation of a stable heparin/PS salt upon the addition of the PS to the FXa/ATIII/H mixtures, thereby effectively lowering clotting times.