NP-40 replacement?

David L. Haviland, Ph.D. dhavilan at IMM2.IMM.UTH.TMC.EDU
Fri Aug 1 10:14:43 EST 1997

At 13:08 8/1/97 GMT, John S. Walker wrote:
>I'm in a physiology lab that does some 2D-PAGE. Our IEF recipe calls for
>NP-40 but our supplier recently told us that this is no longer
>available.  Is this true or is it our supplier is no longer carrying it?
>IF it is true, can anybody suggest a good replacement?


This is true, and sadly so.  However, in lieu of NP40, Sigma recommends the
use of Igepal CA-630, it is chemically (according to Sigma)
indistinguishiable from NP40.  Apparently, NP40 is no longer made.  I've
not tried Igepal.

I've been doing immunoprecipitations  for many years and have done IEFs as
well.  Last I recall, there is not a major chemical difference between NP40
and TX100 and for doing membrane extractions and IP, they are operationally
interchangable.  I'm sure I'll get an argument, but in all my years of
dealing with NP40 vs TX100, I firmly believe you could make the
substitution without seeing a difference in your experiment.  I'm sure
there are some applications where the substitution couldn't be made but
membrane extracionts isn't one of them.

Hope this helps,

 David L. Haviland, Ph.D.
 Asst. Prof. Immunology 
 University of Texas - Houston, H.S.C.
 Institute of Molecular Medicine  
 2121 W. Holcombe Blvd.  
 Houston, TX  77030 
 Internet:"dhavilan at" 
 Voice: 713.500.2413  FAX: 713.500.2424
Never take life seriously. Nobody gets out alive anyway.

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