Effect(s) behind protein-precipitation? - by using ammonium acetat (Mar/15/2006 )

HI!
Why do proteins precipitate when i add ammonium-acetat to my batch?

I just heard it's maybe somethink like "out-salting" - the hydrat-envelope arround the protein (is that the correct term?) is weakend by the salt that also tries to form a hydrat-envelope. What salts can be used vor precipitation?

....

thanks for your ideas

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ammonium sulfate is commonly used. sodium chloride can also be used. i guess most ionic salts can be used.

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salts may not be the right choice if later on they will be difficult to remove, in case they affect the downstream procedure you need to perform.

you can always try TCA or acetone precipitation.

no method is 100% perfect, but it depends what you want to do with your sample after precipitation

good luck

marcfe

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Which TCA do you mean?
# TCA is shorthand for 2,4,6-trichloroanisole, the chief cause of cork taint in wine.
# TCA is an acronym for trichloroethane, an organochloride solvent
# TCA is an acronym for trichloroacetic acid, a chemical used to precipitate protein in serum.



It's for a DNA extraction (genomic bacterial DNA) - so i don't want my genomic DNA to precipitate - My problem is, that most protocols are made for plasmid-extraction - in these protocols they don't care about the greater effect of precipitation of gDNA,...

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