Stabilization of protein for injection in mice - when storing protein in freezer (Apr/20/2006 )

Dear all,
I am presently purifying a protein that I want to inject in mice.
After purification steps, I want to change buffer over a PD-10 column and store the protein at -80 or -20. Previously I have stored proteins in 10% glycerol (not for injection in animals). However, glycerol should be pro-inflammatory, why I am looking for other simple stabilizers (to avid precipitation).
The final buffer should be PBS with stabilizer.
Can I use PBS+sucrose to store proteins for injection?
Thanks a bunch,
Ras

hello,

some people stabilize proteins in 250 or 300 mM sucrose w/ success. i'm curious though...do you know your protein will precipitate when stored at -80 or -20C? if not, do you have a way to verify that it still has normal activity? if the proteins stays soluble and has normal activity, then there's no need to introduce additives into your storage buffer.

the other alternative is to store your protein in glycerol/PBS, and then remove it (i'm assuming you're not going to be injecting large volumes of this into the mice) by some sort of de-salt column (like the P6 spin columns by bio rad) immediately prior to your innoculation. i've had some experience w/ them, and they work quite well. the good part is, they're easy and fast.

one note about the spin columns...the resin is acrylamide, and so you need to block the resin w/ 1% BSA to make sure you don't crosslink your protein to any un-polymerized acrylamide. after that, perform two rounds of equilibration with your buffer and you're ready to go. in total, this takes about 5 minutes. good luck.

Protein stabilization... A common enemy for all the ppl dealin with proteins ..
A very easy solution would be to lyophilize your protein and then reconstitute it when you require it for immunization. If not i think storing it at -20 C would be sufficient. You could also add serum into it to protect your protein. I have read of certain ppl addin thimerosal but i am not sure if it is in your best interest to do so.. best is to lyophilize it... [size=7]