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elution - water elution (Oct/10/2007 )

may i know why water is used in the elution of phenyl-sepharose column?


not just "water" but milli Q water as far as i know. this is by far the most clean water you can get.

This probably depends on what you are trying to do with the column and because you dont want to tell us i can only guess.
As far as i know you dont use MQ water for elution but rather PBS or an EDTA solution.
the MQ water is used later to regenerate the column. you would use it to cleanse the remaining salines and EDTA from the column with it.

what you CAN do with MQ water is to use a decreasing salt gradient to wash bound proteins out of the column.


QUOTE (wayne86 @ Oct 10 2007, 10:16 PM)

phenyl-sepharose (ps) binds proteins based on their hydrophobicity. in order to bind the protein to ps you have to increase its hydrophobicity. this is done by increasing the salt content of the medium (usually ammonium sulfate but sometimes other salts, including sodium chloride).

to release the protein from the matrix you must reduce the hydrophobicity (increase hydrophilicity). to do this you decrease the salt concentration of the medium.

so, you can use water to elute proteins from ps (although, sometimes you need a helper like ethylene glycol to enhance elution). or, more likely, a gradient from high salt to water to separate the proteins bound.