Counterion diffusion in heparin solutions

✍ Scribed by P. Tivant; A. Perera; P. Turq; L. Belloni

• Publisher: Wiley (John Wiley & Sons)
• Year: 1989
• Tongue: English
• Weight: 437 KB
• Volume: 28
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360280609

✦ Synopsis

The physiological importance of heparin is due to its strong interaction with bivalent counterions, especially Ca". A diffusional approach of this property is presented in this article: the observable is the self-diffusion coefficient of the counterions, as a function of the ratio of the polyelectrolyte over the added salt concentrations. All the results are in agreement with a simple "quasi-chemical model" in which two different states are assumed for the counterions: "free" or "bound." The proportions of these two types of ions are calculated according to the distribution function of the counterions around the polyion. We assume that those of counterions located at a distance closer than a, the characteristic distance, are bound; the others are free. The ionic distribution function is evaluated by a numerical integration of a cell model Poisson-Boltzmann equation. Finally, this model leads to a very good agroeement with the experimental results, if the radius of heparin polyion is assumed to be 6 and 10 A.