can i freeze supernatants for western blots? - (May/03/2005 )

Hi everyone,

I'm going to sonicate cell suspensions and use the lysate in western blots. the question is, can I freeze the lysates to use at a later date?

Thanks!!

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Hi batgirl,

Absolutely, but try to avoid too many freeze thaw cycles as this will result in degradation.

Scott

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Thanks Scott! Do I freeze them at -80? would I need to add anything to the lysate to protect them? Sorry, I'm a novice at both cell culture *and* westerns so I'm a bit stuck on this one!

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Hi batgirl,

Depends how long you want to keep them. I usually freeze just in the lysis buffer. If I think I'll use it within a week or two at most I'll store it in the -20C. For longer term stroage -80C. Also different proteins will react differently to storage, if you are looking for protein modifications ie. phosphorylation, acetylation etc. I would try and use as fresh tissue as possible. Also I'd try and snap freeze in liquid nitrogen or at least dry ice. However, if you are just looking at a stock standard protein than throwing it in the freezer for a couple of weeks shouldn't hurt it.

One priviso though, while most of the time this is fine some proteins are very susceptible to degradation and then storage with glycerol or other additives might help, however, you won't know untill you give it a go and see it on a gel.

Cheers,

Scott

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