Effects of protein–protein interaction in ultrafiltration based fractionation processes

Abstract

This paper discusses the use of pulsed sample injection ultrafiltration (UF) for investigating protein-protein interaction, particularly its effect on protein transmission through UF membranes. Several binary protein mixtures were investigated; the proteins in each mixture being selected such that one of the proteins in the pair would be preferentially transmitted while the other would be either totally or substantially retained. The "retained" protein either decreased or increased or did not affect the sieving coefficient of the "transmitted" protein, this depending the type of protein-protein interaction, that is, associative, repulsive, or neutral. The type of protein-protein interaction depended on the particular protein pair under investigation as well as on the operating conditions used (pH and salt concentration). The magnitude of either decrease or increase in transmission of a preferentially transmitted protein due to the presence of a retained protein was found to be independent of the manner in which the proteins were injected into the system, that is, simultaneous or sequential. These magnitudes however correlated well with the ratio of the two proteins present in the feed.

High Purity of α-Lactalbumin from Binary Protein Mixture by Charged UF Membrane Far from the Isoelectric Point to Limit Fouling

“…Furthermore, BLG, being prevalently present in dimeric form, is also retained from the membrane, but when the initial protein concentration is further increased, the reversible fouling, due to the accumulation of the most rejected protein, also increases, causing the passage of BLG monomer. The higher passage of ALA through the membrane, before BLG concentration increase in the retentate, was also given by an associative affect between the two positively charged proteins due to the Donnan effect, as already reported in the UF of different binary protein mixtures [2,32,33]. In this particular condition, the largely retained BLG (prevalently in dimer form) tends to push the more transmittable ALA (present as monomer, and less charged) through the membrane to permit charge balance.…”

Association of Valdecoxib, a Nonsteroidal Anti‐Inflammatory Drug, with Human Serum Albumin

“…Furthermore, the treatment gives directly the free solute concentration and its validity is independent on the quenching mechanism (dynamic, static or mixed). In many senses this procedure, based on steady‐state fluorescence measurements, has the advantages of the physical separation without the experimental problems associated with these methodologies .…”

Continuous fractionation of plasma proteins HSA and HIgG using cascade ultrafiltration systems

“…In the pulsed injection experiment carried out to generate the above profiles, permeate samples were collected and analyzed by Protein-A affinity chromatography to determine the exact protein composition. The feed composition corresponding to the individual permeate samples were estimated [30,31]. Fig.…”

“…The experimental method used in this work was similar to that discussed in [31]. The ultrafiltration module was similar to that used in the fractionation experiments described in the previous section.…”