Protocol Online logo
Top : Forum Archives: : Protein and Proteomics

Protein formed ppt after stored at -80oC - (Sep/01/2006 )

Dear All,

I purified my overexpressed protein from E.coli by His column yesterday. I kept the protein at
-80oC fridge. Today, I got it back from the fridge. After I thawed the protein. There were some ppt and these ppt cannot be dissolved.

Do anyone have this experience? How to dissolve them?

thx very much!!!!

siuchi

-siuchi98-

well, i've nerver faced that, but noticed that BSA forms pellets that are removed by 25° heating.
You may heat an aliquot of your sample (containing some of the ppts) gently and see what happens

-fred_33-

Were your proteins only in PBS? If they are freezed in PBS without glycerol and they are too much concentrated, they might precipitate.

-mprime4-

the protein may have been denatured by ice crystal formation. you may be able to suspend it in denaturing conditions (eg- sds, urea, etc) but it would not regain function.

-mdfenko-