I'm searching for any information regarding the stability of tween20 (polyoxoethylen (20) sorbitan monolaurate). We employ this detergent as a component of the reaction media in which we study the enzymatic activities of dengue virus NS3 helicase. We added it to the reaction media since it was observed that NS3 specific ATPase activity was dramatically reduced by dilution and it was observed that the addition of tween20 (about 0.05% w/v was enough) eliminates such dilution effect. Now we have the following problem. Aqueous solutions of tween20 lose their protective activity upon storage (in the refrigerator and protected from light). We haven't assessed its stability yet and we just don't know how much storage (at low or at room temperature) is admissible in order to obtain reproducible enzyme activity measurements. Any information regarding measures toavoid tween20 degradation could be highly valuable for us.
Tween is prone to oxidation If your stock solution is yellow then it probably has some reactive oxygen species in it. Normally this is not a big problem, but your system could be very sensitive to those reactants.
You could try switching to octylglucoside or use tris or other primary amine buffers to (hopefully) neutralize the most reactive species.
Is stability is still important, u could start looking at possible reasons one by one. First thing i would do is use autoclaved water to prepare working solution of t20.
Hi Apurva,
Thaks for your answers. We finally start preparing tween20 solutions just prior to use. Besides the remaining problem of possible degradation during experiments and during storage of commercially available tween20, it would be convenient to be able to prepare and use stocks solutions for a couple of experiments.
Regarding the use of autoclaved distilled water, we didn't tested it so far. Since experiments are conducted in the presence of RNA, we always use distilled and filtered water which is proved to be RNAse free. So i don't think autoclaving could help increasing the stability of tween20 solutions. But i'll tried it anaway.
Tween is prone to oxidation If your stock solution is yellow then it probably has some reactive oxygen species in it. Normally this is not a big problem, but your system could be very sensitive to those reactants.
You could try switching to octylglucoside or use tris or other primary amine buffers to (hopefully) neutralize the most reactive species.
Good point Steingrimur. I'll try degassing tween solutions and, possibly, the addition of an antioxidant reagent. And i could eventually asses the peroxide content of tween solutions as a function of storage time. Thank you.
The cmc of Tween20 is lower at lower temperature. The same concentration of Tween20 at higher temperature could have a denaturating effect on the protein at lower temperature. As for Tween20, we always keep aquous solutions in fridge, when filtered and degassed it remains stable over very prolonged periods of time.
Very interesting Julie. I'll take into account the effect you mentioned above -of temperature on the cmc of tween20- when we begin working at variable temperatures. And for the other part of your answer, we will try following your indications of filtering and degassing. Thank you!
If your tween is at too high a concentration, it will form aggregates at lower temperature. Check the cmc concentration, what concentration you are storing it at, etc.
I always use Pierce's SurfactAmps Tween-20, which comes as a 10% solution in glass ampules under inert gas. After opening an ampule, which contains 10 ml, I store the solution in 1 ml aliquots at -20 C. I use these to make my solutions for each day's experiments. I don't store the solutions containing dilute Tween-20 beyond the day I make them. This avoids the problem of oxidation of the detergent.
Tween-20 is prone to oxidation in the presence of metal ions, phenolics and other redox reagents. Autoclaving is NOT recommended! I'd suggest trying the reaction with different concentrations since there are some enzyme reactions that are inhibited by tween-20!
With any reagents that are commercially available, it is always best to check out the manufacturer's recommendation for storage conditions, recommended dilutions, and stability. This will prevent unnecessary testing and errors in analysis because the manufacturers usually perform quality control, shelf life, and stability evaluation at various conditions. Different manufacturers usually have different recommendations so it is always best to check with them first. Basic information is included in the product specification sheets which are usually available at the manufacturer's website.
Is the Tween 20 aqueous solution is thermo degradable at room temperature
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