Hi everyone, may i know how proteins can be preserved upon purification? I need these proteins for downstream activity tests but as I will not need them right away, I need some solutions to preserve them. Is glycerol 10% with the elution buffer ok? By the way, I did His-tag purification. Thanks in advance!
Firstly, I would get rid of the imidazole in your eluted protein using a desalting column, e.g. PD-10 or equivalent. Often, imidazole destabilises proteins, and it may also interfere with downstream assays.
The best way to preserve most proteins is simply to aliquot in 100 µl or less volumes into thin-walled PCR tubes/strips and flash freeze in liquid nitrogen before placing at -80 C. If you do this, no glycerol is necessary for the large majority of proteins.Here is a paper describing that method:
http://www.ncbi.nlm.nih.gov/pubmed/14684931
Some proteins don't survive flash freezing, in which case supplementing with 50% glycerol (to prevent freezing) and storing at -20 C, as suggested by Adam, is a good method.
Adam, a little clarification would help as to the purpose of the preservation. In the MEF process we preserve the proteins produced by drying in either a complete state or denatured... either works well for our purposes.
Hi Adam, if your protein is labile, you should store it at -80oC in small aliquots. 10% glycerol is OK.
Flash-freeze your protein in small aliquots with 10 or 20% glycerol and store at -80 C, or keep unfrozen at -20 C with 50% glycerol.
Hi Edward, the purpose of preservation is just so that I can purify different proteins and have them all ready before I proceed with the activity assay. Thank you.
Firstly, I would get rid of the imidazole in your eluted protein using a desalting column, e.g. PD-10 or equivalent. Often, imidazole destabilises proteins, and it may also interfere with downstream assays.
The best way to preserve most proteins is simply to aliquot in 100 µl or less volumes into thin-walled PCR tubes/strips and flash freeze in liquid nitrogen before placing at -80 C. If you do this, no glycerol is necessary for the large majority of proteins.Here is a paper describing that method:
http://www.ncbi.nlm.nih.gov/pubmed/14684931
Some proteins don't survive flash freezing, in which case supplementing with 50% glycerol (to prevent freezing) and storing at -20 C, as suggested by Adam, is a good method.
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