re detergent removal

Robert Preston rapr at MED.PITT.EDU
Wed Jun 22 22:37:28 EST 1994

Forwarded message:
> From: scott_basehore at
> Subject: detergent removal help!
>           two detergents. Dialysis won't work as the detergents are
>           above the critical conc. for the formation of micelles. I
>           have tried an Extracti-gel D (Pierce) column, but the
>           solution still foams when agitated (low-tech assay).  I am
>           fairly sure that my enzyme alone will not foam at its
>           present concentration.  Does anyone know a method for
>           removing these detergents?  How might one assay for the
>           presence of detergents?

As others pointed out, dialysis should work regardless of cmc because
micelles are in equilibrium with monomers.  I don't know about the
Pierce column or the methods mentioned by other respondents, but I
wonder how you can know that the enzyme would not foam by itself.
If it does (regardless of your expectation) and you insist on a non-
foaming result, you can't possibly win.  My experience is that it's
sometimes pretty hard to get deionized distilled water not to foam,
depending on the cleanliness of the containers and the phase of the
moon: (mild amounts of) "foaming" can be an extremely sensitive assay
for random junk (or for your favorite protein), which you might mistake
for traces of unremoved detergent.

rapr at

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