... protein people dont keep their "pets" at -20 ... (better
snapfreeze&store-80C or keep in lN2)
David
2009/2/27, Pow Joshi <pow.joshi from gmail.com>:
> 2009/2/27 <marguerite.b.colas from gsk.com>
>>> Hello Peter!
>>>> I work at a pharmaceutical company and have been working on this study
>> that involves freezing hemoglobin proteins, Every time we thaw our samples
>> we notice that they go cloudy.
>> At first we thought that we had been mixing our cell membrane pellet with
>> the cell content supernatant. However, the time we took extra care to
>> distinguish the supernatant from the pellet, we still noticed that our
>> samples went cloudy after thawing them from the freezer. All our samples
>> are kept in a -20c freezer.
>>>> If you think you might know what might be happening to our samples, please
>> let us know!
>>>> methinks, you could try adding extra salt to the supernatant; or check the
> pH .... these are Fe bound proteins are'nt they?, perhaps if you need to
> have near neutral pH? ... I wonder if the Fe is forming hydroxides and
> precipitation out ...., in which case, you could add a bit of acid and
> resolublize? ....... Dima, may be you will be able to answer if I'm
> completely off the track?
>> Pow
>>>>>>> thank you very much for your attention!
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--
David Minde MSc (TUM)
Cellular Protein Chemistry Room 707
Department of Chemistry
Faculty of Science
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Science is what happens while we are making other plans (~John Lennon)
