I would like to store biological samples containing biotinylated proteins at -80 °C for several weeks, before continuing protein extraction and streptavidin affinity purification. I was wondering whether the biotin-protein bond is stable for long periods at -80 °C? Thank you for your advice.
We use a lot of biotinylated antibodies. We expect them to be stable for at least 5 years in a refrigerator and longer frozen. The biotin label is very stable so it should last for many years if stored frozen.
Yes Lucas, you can store biotinylated proteins at -80C for a while.
During my grad studies, I have purified several biotinylated proteins and stored them at -80C for a while (few weeks to a month) for my experiments and they work fine(*and biotin bond is stable). Please avoid frequent "freeze and thaw" cycles. Instead, aliquot purified protein into smaller fractions and store protein, after flash freeze (using liquid nitrogen).
The biotinylation is unlikely to be a problem, if your protein itself is stable under your conditions. Most proteins are, some are not (especially in complex mixtures where proteases may be present).
As Kiran-Kumar Shivaiah pointed out, freeze-thaw cycles can be a problem. Apart from his solution to freeze the sample in aliquots you may also consider storage at -20 °C in a glycerol-containing solution. At this temperature, solutions between 50 and 75% glycerol remain liquid, the eutectic is 66.7% with a freezing point of -46.5 °C. I have used this method to store labelled secondary antibodies and found it reliable and convenient.
Lucas Mergan
Most of the proteins are stable at - 80 dergree C, but must avoid freeze- thawing.
you can make aliquots and try to use them once.
- Badges
- Science method