Molecular cloning -Sambrook et al/ Tris base vs TRIZMA

Pamela Norton pnorton at lac.jci.tju.edu
Thu Jun 8 16:50:46 EST 1995


In article <Stephen_Lasky-0606951937500001 at poncho-slip5.cis.brown.edu>,
Stephen_Lasky at brown.edu (Stephen R. Lasky, Ph.D.) wrote:

> > buffers with Tris base (we get it from Gibco/BRL, no affiliation,
> > presumably other sources work as well) instead of Trizma. I too was
> > skeptical but tried this as a last resort based on the comment in Sambrook
> > et al. The difference was astounding. 
> >     
> 
> Pam:  No!!!!!   8-)   Tris base and trizma are the same things.  Look them
> up in your Merck index.Trizma is just sigma's trade name for tris base
> (you'll notice the registered trademark mark on sigma's trizma): 
> trishydroxymethylaminomethane.  MW=121.1, mp=171 to 172 for both tris and
> trizma.  I have been using trizma or tris interchangably for 20 years now
> and never could ascribe the problems you cite with your gels to using tris
> or trizma (I am using the molebiol grade from trizma from sigma as well as
> tris from gibco/brl). .  Empirically, you may have solved your problems
> when you changed from Trizma to tris, but I would suspect a pHing problem
> or bad water (especially if the problem was at RWMC), or lower quality
> trizma/tris.



					I fear that I was not as clear as I could have been. I wanted to
emphasize the importance of using the _base_ form of Tris, not Tris-Cl, and
I agree that Trizma _base_ should work just fine. I must confess that I do
not know just which Trizma of the many in the Sigma catalog gave us the
problem, I've moved since then. I do not know why Sambrook et al
specifically recommend against using Trizma as well as Tris-Cl (they do).
However, I'm quite sure that our problem was not due to water or Glycine,
as others have suggested (Hi Steve!), although I have no doubt that a bad
lot of Gly or low quality H2O can cause problems. I guess that we were
using the wrong form of Trizma - in other words, be careful to pick the
_right_ form.

					Sorry if I added to the confusion rather than helping. 

					On a related note, Sambrook et al also claim that different brands of
SDS can result in significant differences in mobility of bands in SDS-PAGE
gels, and they recommend that one pick a product and stick to it. Has any
one observed this problem? Just curious.

-- 
Pamela A. Norton, Ph.D.          Assistant Professor of Medicine
Thomas Jefferson University
Philadelphia, PA 19107           p_norton at lac.jci.tju.edu



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