I thought about HIC too, but do not know if it would work since the
binding of protein to HIC need high salt conc. and I am not sure if the
salt conc. in the sf900 or Hi5 medium is high enough (the formulation is
secret, LOL), thus it is good to know that someone has succesful
experience with HIC.
Few things:
1. With regard to the salt/ionic strength, the formulation of serum-free
media cannot be far off from the traditional media. Very crudely speaking,
figure an equivalent of ~200 mM NaCl. So most protein won't bind to, say,
phenyl sepharose under these conditions. But "your" protein might be in the
minority - who knows?
2. What prevents you from adding extra salt to the collected medium? Say,
~1 M ammonium sulphate final? There probably will be some precipitate
forming which can be filtered away before loading onto a HIC column.
3. Hydroxylapatite. "Ceramic Type I" version from Bio-Rad in particular.
Large size beads packed into a wide column. A great way to concentrate
total protein at high flow rates. Phosphate concentration in the medium is
low enough that majority of proteins will sill bind.
- Dima
