Hi, perhaps this link is useful http://www.4adi.com/ccp10501-recombinant-human-brain-derived-neurotrophic-fact-rec--protein-bdnf11-r.htm

They sell a protein purified by RP-HPLC and Ion exchange.

So, I guess, you could try solubilizing the inclusion bodies with urea (not retained in RP-HPLC due to its highly hydrophilic nature). Then you can run the protein on a reverse phase column and finally on a MonoQ or similar. The urea can be maintained until the MonoQ step and you can try to refold in the column (inverse urea gradient when protein is bound to it) or after the purification (e.g. dialysis against buffer without urea).

HTH

Marco

Bringing an insoluble protein to soluble form is a bit tricky and needs different parameters to be checked.

You could try optimizing the temperature, time, conc. of IPTG, host cells, vector etc

Additives like gly-gly, glycerol, ethanol can also be tried.

When all these fails you can try solubilizing using detergents like urea, NP40, Sarcosine, Arginine Monohydrate etc. However the conc. of these detergents needs to be optimizing as it tends to denature the protein of interest.

Hope it helps