thank you Patricia! i have learned so much from everyone oin this group. when would i have a chance to talk with scientists working with this sort of thing. only wish i could go back to school for the rest of my life andlearn everything that i want to know. so once again, thanks for teaching me something new. dorlis ---- patricia.a.elk...@gsk.com wrote: > Interferon is a protein. It is dried into a powder which should be able > to be frozen with > no problem. But when proteins are dissolved into a liquid solution, > freezing can be tricky. > As a scientist working with a variety of proteins, I can tell you that > many proteins will start > to break down if frozen more than once. And rapid freezing is preferable > to slow freezing. > At home, the closest thing to rapid freezing could be done by putting the > protein tube into ice in the back of > the freezer lowering > the temp more rapidly than if you just stick it on the shelf in the > freezer. Proteins also generally > survive freezing better if they are more dilute and freezing in smaller > portions will allow the > freezing to go faster than freezing in big portions. > > If a protein is degraded by freezing, it's structure starts to unwind. > Some molecules of the > protein in the solution may degrade and others won't so you may still see > that the protein has > some activity or it may lose all activity. You might see some precipitate > in the solution (always > a bad sign) or you might not. Without some kind of activity readout, it > seems impossible > to me to know whether freezing is causing a problem. > > In summary, I would make up the solution to the appropriate dilution and > freeze it in the smallest > portions that will work (need appropriate sized containers) in the coldest > part of the freezer in ice. > _______________________________________________ > Felvtalk mailing list > Felvtalk@felineleukemia.org > http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org
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