Abstract
Partitioning of proteins in aqueous two-phase systems has been shown to provide a powerful method for separating and purifying mixtures of biomolecules by extraction. These systems are composed of aqueous solutions of either two water-soluble polymers, usually polyethylene glycol (PEG) and dextran (Dx), or a polymer and a salt, usually PEG and phosphate or sulfate. There are many factors which influence the partition coefficient K, the ratio of biomolecule concentration in the top phase to that in the bottom phase, in aqueous two-phase systems. The value of the partition coefficient relies on the physico-chemical properties of the target biomolecule and other molecules and their interactions with those of the chosen system. In this work, the partition behavior of pure bovine serum albumin in aqueous two-phase systems was investigated in order to see the effects of changes in phase properties on the partition coefficient K. The concentration of NaCl and pH were considered to be the factors having influence on K. Optimal conditions of these factors were obtained using the Box-Wilson experimental design. The optimum value of K was found as 0.0126 when NaCl concentration and pH were 0.14 M and 9.8, respectively, for a phase system composed of 8% (w/w) polyethylene glycol 3,350 - 9 (% w/w) dextran 37,500 - 0.05 M phosphate at 20 °C.
Similar content being viewed by others
References
Albertsson PA (1986) Partition of Cell Particles and Macromolecules. John Wiley and Sons, New York.
Backman L and Shanbhag VP (1984) Simplex optimization in biochemistry: application of the method in two-phase partition. Anal. Biochem. 138: 372–379.
Box GEB, Hunter WG and Hunter JS (1978) Statistics for Experimenters. John Wiley and Sons, New York.
Johansson G (1970) Partition of salts and their effects on partition of proteins. Biochim. Biophys. Acta 221: 387–390.
Brooks DE, Sharp KA and Fisher D (1985) Theoretical aspects of partitioning. In: H Walter, DE Brooks and D Fisher (eds) Partitioning in Aqueous Two Phase Systems. Academic Press, New York: John Wiley and Sons, New York.
Zaslavsky BY, Bagirov TO, Borovskaya AA, Gulaeva ND, Miheeva LH, Mahmudov AV and Rodnikova MN (1989) Structure of water as a key factor of phase separation in aqueous mixtures of two nonionic polymers. Polymer 30: 2104–2111.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gündüz, U. Optimization of bovine serum albumin partition coefficient in aqueous two-phase systems. Bioseparation 9, 277–281 (2000). https://doi.org/10.1023/A:1011194324047
Issue Date:
DOI: https://doi.org/10.1023/A:1011194324047