Saponin is isolated from Quillaja bark. It is a glucoside with a high affinity for
cholesterol. It will replace the cholesterol in the membrane and make pores big
enough to have Ab's enter the cell (Willingham, et al.). Since the
intercalation is a reversible process it is important to have saponin present in
all your incubation and wash steps. Minimum concentration is 0.1%. Normally used
in concentration between 0.2 and 0.4%. This mainly depending on the batch since
the purity of the isolation is not always as good. The browner the preparation
the higher the the concentration has to be.
This widely used non-ionic surfactant is a detergent which permeabilizes
the cell membrane. It is often used to isolated membrane components under
non-denaturizing conditions. Just as for Saponin hold true; too high
concentrations simply will dissolve the cells.
n-octyl-ßD-glucopyranoside or n-Octyl glucoside has the same
characteristics as Triton. This chemical is also an non-ionic detergent used
for the solubilization and isolation of membrane proteins.