Isolation of secreted proteins - (Apr/17/2008 )

Hi,

Does anybody have any ideas as to how to go about isolating proteins secreted in media of cultured cells?

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you have to concentrate your protein f.i. by ammonium sulphate precipitation, and then design a protocol for (column) chromatography; it depends on physico-chemical porperties of your protein

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You need to concentrate, as said by the Bearer. As an alternative to precipitation, you can use transverse flow filtration (TFF), which has the advantage over precipitation that it doesn't change the salt conditions; it is ,however, slower. You can combine TFF with diafiltration if you want to change the buffer conditions.
We used to concentrate 1l of media to ~50 ml with TFF and diafiltration in a day, and still have time to clean the apparatus.

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