Protein Sample - How to store it? (Nov/13/2007 )

I just purified my protein. It is really hard to judge what is the right temperature to keep the sample. I just put it in normal 4 degree. It has been a week and I just ran a SDS PAGE analysia. The protein is still there. Now there is another thing. I need to send the sample to London via courier.

Should I send it using normal courier?
Or using normal ice?
Or using dry ice?


What temperature should I keep for my own use? -20 or 4 Celcius?

I think the protein is quite stable. So I am not really sure how to send it over (I think it needs about a day to send over).

Thanks.

I always store my proteins at -20°C, some also do at -80, but I think, this is only necessary for long time storage of sensitive samples. Is your protein phosphorylated? You could lose phosphorylations, if it gets to warm and phosphatase or proteases get active, if there are no inhibitors for them in your sample. So, I would keep to -20°C and sending on dry ice. Only, if it is in laemmli-buffer, I think sending on normal could not harm so much, if it is already denatured.