The effect of membrane filtration upon protein conformation
Truskey, G.A.; Gabler, R.; DiLeo, A.; Manter, T.
Journal of Parenteral Science and Technology a Publication of the Parenteral Drug Association 41(6): 180-193
1987
ISSN/ISBN: 0279-7976 PMID: 3325627 Document Number: 302977
Conformational changes of three proteins were investigated upon passage through different membrane filters. Three different pore sizes and three differential pressures were examined. Protein conformational changes were detected using circular dichroism measurements both before and after filtration and replicate measurements were performed to examine the reproducibility of the results. No spectral changes were observed for filtration through a polyhydroxypropylacrylate grafted polyvinylidene difluoride membrane and replication was excellent. Some spectral differences and variability in replicates were observed for a polysulfone membrane. Many differences in spectra were seen for filtration through a nylon membrane and the results were very variable. In all cases the spectral changes did not seem to be correlated to either pore size or applied pressure. Hydrodynamic variables in the form of shear stress are probably not the cause of any conformational changes, while the membrane's ability to bind protein seems to be more closely related to conformational changes.