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Aggregation kinetics in salt‐induced protein precipitation
Author(s) -
Przybycien Todd M.,
Bailey James E.
Publication year - 1989
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.690351104
Subject(s) - turbidimetry , supersaturation , chemistry , protein aggregation , kinetics , precipitation , salt (chemistry) , hydrodynamic radius , monomer , solubility , protein precipitation , dynamic light scattering , population , chromatography , biophysics , chemical engineering , polymer , aqueous solution , organic chemistry , biochemistry , meteorology , physics , demography , quantum mechanics , sociology , nanoparticle , engineering , micelle , biology , analyte
The kinetics of protein aggregation in salt‐induced precipitation processes were studied as a function of salt type, salt concentration, temperature and protein concentration. α‐chymotrypsin (αCT) was used as a model protein. Stopped‐flow turbidimetry was used to monitor the progress of precipitations. Analysis of the linear portions of the turbidity trajectories indicates that temperature and salt concentration effects are related to protein solubility; the protein concentration dependence is well described by the Smoluchowski collision equation. The aggregation kinetics of partially‐inhibited αCT exhibit poisoning behavior, underscoring the importance of dimerization and monomer addition in the precipitation of αCT. Solute particle radius distributions determined via dynamic laser light scattering for low salt and supernatant αCT solutions indicated that significant aggregation does not occur in the absence of supersaturation. A detailed population balance model was proposed that accounted for specific and nonspecific interactions and monomer addition. The model is expected to find general application to protein aggregation phenomena, in particular for proteins that have specific quaternary interactions.