Can I use Apollo to remove larger molecules and expect to quantitatively recover a protein that passes through in the filtrate?
This application, known as fractionation, is difficult. Two variables are important to effectively fractionate proteins. The polarization of the larger molecule will tend to increase the retention of the smaller protein. Controlling filtration rate and protein concentration can minimize this effect. Spinning more slowly and diluting the sample beforehand will improve performance. Another consideration is that the polyethylene microporous support of the composite Apollo UF membrane can tend to adsorb many proteins passing through it as filtrate. If the desired protein in the filtrate is very dilute and hydrophobic, the membrane support material may adsorb much of it before the surfaces become saturated. In this case, prior to use, an innocuous protein or other material may be used to block the binding surfaces in the polyethylene to improve permeate recovery.
