Storing Purified Proteins - Seeking a Preservative (Oct/28/2009 )

Hello All,

Looking for suggestions here.

I'm trying to find something that isn't toxic to help preserve purified proteins that are stored at 4C. I know everyone uses NaN3 for this purpose usually, but I can't/won't. The proteins are stored upto a fortnight at 4C and any preservatives added shouldn't interfere with their function.

Has anyone had experience using commercially available preservatives used in the cosmetic/food industry for such purposes? I'd be interested to hear your thoughts.

Thanks,

The Ace

-TheAce-

Preserve in what sense?? NaN3 will be added to prevent contamination if i am not wrong...
Yo want to presenrve it in terms of saving it from aggregating or deamidating or oxidising, or you just wanna store it without a contam watever the forms generated??
If used filtered buffers, the protein should be good for a fortnight and you need not add any preservatives!!!
Please clarify if this is what you needed or elaborate your querry!!!

-Pradeep Iyer-

The "best" way would be to lyophilise your protein.

-bob1-

bob1 on Oct 30 2009, 05:49 AM said:

The "best" way would be to lyophilise your protein.

I agree to taht too!! Why dint i think of it.. we do it tat way here some times!!!
May be a dull day ahead

-Pradeep Iyer-

bob1 on Oct 30 2009, 05:49 AM said:

The "best" way would be to lyophilise your protein.

and also if the impuriteis that you are talking about is aggregation.. then beware.. lyophilization can increase aggregation.. unless less amount is lyophilized!!!

-Pradeep Iyer-

CellSpecific.com on Oct 29 2009, 10:55 PM said:

Another option for you is to flash-freeze (in dry-ice/ethanol bath or in liqN2). You can store the frozen aliquots in -20C for later use. Be sure to try this out with an aliquot of your protein and determine whether activity and integrity remain unchanged before freezing down a significant amount. We've used this approach with many proteins from antibodies to smaller cytokines. Anyone else want to comment on their experience with this method of "preserving" proteins?

Yeah, that works pretty well, but the OP wanted some way to store at 4 ˚C.

-bob1-

one of the problems with storing proteins at 4C is the stability of -sh groups. the protein may form s-s bonds, thereby aggregating and denaturing the protein. you may add 0.5-2mM dtt or 5-10mM mercaptoethanol to preserve the -sh groups.

-mdfenko-