yes, you can do that if your protein does not involve any domain activity and protein folding for its activity.

As normal it act like freeze thaw mechanism for cells.

It is better to extract immediately

However you can store cells at -80C and then extract later

I would caution however about flash freezing cells and then freezing at -80C: you might be better to freeze initially on dry ice (assuming by flash freezing you mean liquid nitrogen) to minimise shear damage incurred by ice crystals

If your flash freezing protocol involves 1 hour on dry ice followed by transfer to -80C then this is fine

In my understanding it is completely fine to freeze your cells at -80C. Though, as suggested in the preceding answer, it is of much worth to let them go to such chilling temp gradually. Put them at ice or at 4C for some time before shifting to -80C.

Answering to whether protein get denature after freeze and thaw, yes they do, most of them. Its better to keep them in chilling temp, and take out only once when required. Additionally, keeping protein at 4C or at ice to let them attain liquid form are good practice than thawing.

Hope it helps!

Hello Hai,

I agree with Laurence suggestion, and would also add that in many cases freezing a pellet of yeast cells at -20C could be sufficient, but it very much depends on your protein.

Another possibility is to resuspend the cells directly in the lysis buffer you plan to use (with all the goodies such as Protease inhibitors, detergent etc...) and then freeze as above suggested; this way once you thaw the cells, they will immediately face the conditions in which you plan to proceed, and your protein should be relatively protected if some of the cells lyze during the thawing process.

Good luck.

G

i have some problem with my protein after I freeze the cells with liquid N2 and then put at -80 degree.

after i read the previous answers, i summerize as follows:

1, try to lysis right after harvest the cells.

2, if not, put cell pellet in dry ice/ethanol for half an hour, then transfer to -80.

thanks.

Hai, Hello again,

I also suggested to try and freeze the cells at -20C rather then -80C, that could also help prevent you from losing your protein.