storage of taq polymerase - (Jul/17/2005 )
Though taq works well at 72 degree, it is said that it must be kept at 0-4 degree to prevent denaturation. Why it is so?
It is the same as your restriction enzymes working at 37C but we don't leave them at room temperature. I'm no expert on thermophillic bacterial proteins, but one of my collegues used to isolate proteins from them and found that they do lose activity with changes in temperature. For example Taq will last a couple of hours in a PCR (94C, 56C, 72C), a day at room temperature, a month at 4C and considerably longer at -20C. So to prolong the active life of our enzymes we try and store them at lower temperatures.
One word- proteases
Agree with Daniel Tillett
If Taq is new, it could be stored at RT without problem. But when you start working with the Taq, better keep it at -20 C. That's because you might inadvertently introduced proteases (either exogenous or microbe) to the Taq when you opened the Taq enzyme. The low temp. will slow down protein degradation if protease is present.
thank you daniel for your good suggestion.