Phase stability of aqueous mixtures of bovine serum albumin with low molecular mass salts in presence of polyethylene glycol

Hurija Džudžević Čančar (Author), Matic Belak Vivod (Author), Vojko Vlachy (Author), Miha Lukšič (Author)

Abstract

The stability of bovine serum albumin (BSA) solutions against phase separation caused by cooling the system is studied under the combined influence of added poly(ethylene glycol) (PEG) and alkali halide salts in water as solvent. The phase stability of the system depends on the concentration of the added PEG and its molecular mass, the concentration of the low molecular mass electrolyte and its nature, as also on the pH of the solution. More specifically, the addition of NaCl to the BSA-PEG mixture promotes phase separation at pH = 4.0, where BSA carries the net positive charge in aqueous solution, and it increases the stability of the solution at pH = 4.6, i.e., near the isoionic point of the protein. Moreover, at pH = 4.6, the cloud-point temperature decreases in the order from NaF to NaI and from LiCl to CsCl. The order of the salts at pH = 4.0 is exactly reversed: LiCl and NaF show the weakest effect on the cloud-point temperature and the strongest decrease in stability is caused by RbCl and NaNO$_3$. An attempt is made to correlate these observations with the free energies of hydration of the added salt ions and with the effect of adsorption of salt ions on the protein surface on the protein–protein interactions. Kosmotropic salt ions decrease the phase stability of BSA-PEG-salt solutions at pH < pI, while exactly the opposite is true at pH = pI.

Keywords

goveji serumski albumin;vodne raztopine;fazna stabilnost;polietilen glikol;

Data

Language:	English
Year of publishing:	2022
Typology:	1.01 - Original Scientific Article
Organization:	UL FKKT - Faculty of Chemistry and Chemical Technology
UDC:	577.322
COBISS:	93209859
ISSN:	0167-7322
Views:	82
Downloads:	38
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	goveji serumski albumin;vodne raztopine;fazna stabilnost;polietilen glikol;topnost;
Type (COBISS):	Article
Pages:	str. 118477-1-118477-8
Issue:	ǂVol. ǂ349
Chronology:	1 Mar. 2022
DOI:	10.1016/j.molliq.2022.118477
ID:	15721002