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Electrostatic potentials and protein partitioning in aqueous two‐phase systems
Author(s) -
Haynes C. A.,
Carson J.,
Blanch H. W.,
Prausnitz J. M.
Publication year - 1991
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690370912
Subject(s) - chemistry , aqueous solution , partition coefficient , ethylene glycol , electrostatics , lysozyme , aqueous two phase system , bovine serum albumin , phase (matter) , analytical chemistry (journal) , capillary action , cyclodextrin , chromatography , iodide , thermodynamics , inorganic chemistry , organic chemistry , physics , biochemistry
A thermodynamic analysis unambiguously relates interfacial‐electrostatic‐potential differences measured with Ag/AgCl capillary electrodes to the equilibrium properties of an aqueous two‐phase system. Interfacial electrostatic potentials were measured as a function of total α‐cyclodextrin concentration in an aqueous two‐phase system containing 9.1 wt. % poly (ethylene glycol), 6.1 wt. % Dextran T‐70, and 1‐mM potassium iodide. An order‐of‐magnitude increase in the interfacial electrostatic potential was observed as the total concentration of α‐cyclodextrin increased from 0 to 1 mM. Measured partition coefficients for α‐chymotrypsin, lysozyme, and bovine serum albumin depend strongly on α‐cyclodextrin concentration. For example, as the concentration of α‐cyclodextrin rises from 0 to 1 mM, the partition coefficient of lysozyme decreases from 1.7 to 0.55. These measurements are in good agreement with theoretical expectations.