The effects of ligand chain length, salt concentration and temperature on the adsorption of bovine serum albumin onto polypropyleneglycol-Sepharose.
The interaction thermodynamics associated with bovine serum albumin adsorption on polypropylene glycol (n=3)-Sepharose CL-6B and polypropylene glycol (n=7)-Sepharose CL-6B, using ammonium sulfate as the modulator was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model, preferential interaction approach and van't Hoff plots applied to HIC systems. Preferential interaction analysis indicated a strong entropic driving force under linear conditions, due to the release of a large amount of solvent on adsorption. In contrast, flow microcalorimetry under overloaded conditions showed that the adsorption of bovine serum albumin may be entropically or enthalpically driven. It is postulated that adsorption in the nonlinear region is influenced by the degree of water release, protein-protein interactions on the surface, reorientation of ligand, and conformational changes in the protein.
Dias-Cabral
A C
AC
Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal.
Ferreira
A S
AS
Phillips
J
J
Queiroz
J A
JA
Pinto
N G
NG
D000327:Adsorption; D002151:Calorimetry; D008024:Ligands; D011108:Polymers / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D012685:Sepharose / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D008024:Ligands; D011108:Polymers; D011409:Propylene Glycols; D012492:Salts; C012504:polypropylene glycol; D012710:Serum Albumin, Bovine; D012685:Sepharose