Partition behaviour of thaumatin derivatives in poly(etlyleneglycol)/salt aqueous two-phase systems

MIRANDA, MARÍA VICTORIA; FERNÁNDEZ LAHORE, HÉCTOR MARCELO; OSVALDO CASCONE,

BIOSEPARATION

Año: 1996 vol. 6 p. 315 - 321

0923-179X

In order to assess üe influence of the protein charge on its partitioning behaviour in poly(ethyleneglycol/salt aqueous two-phase systems, four thaumatin derivatives with isoelectric points around 4.0, 5.2,8.7 utd 9.2 were obtained by succinylation and isolated by isoelectric focusing and chromatofocusing. The modification reaction was mild enough to preserve the tertiary structure of the proteins, as judged by circular dichroism measurements and fourth derivative UV specha. The surface hydrophobicity of the thaumatin derivatives with pls 5.2,8.7 aÍd9.2 - as determinedb y hydrophobici nteractionc hromatography- was not modified by the succinylationt reatment. Partition constantso f the derivativesi n poly(ethyleneglycol)/phosphatec,i trate and sulphatea queoust wo-phase systems at pHs between 7.0 and 9.5 indicate that the partition is not dependent on the protein charge in the poly(ethyleneglycol)/salts ystemss tudied.