Molecular cloning -Sambrook et al/ Tris base vs TRIZMA
hroychow at NMSU.EDU
Mon Jun 5 16:11:37 EST 1995
On 5 Jun 1995, T.S. Pillay wrote:
> In the electrophoresis section in Molecular Cloning by Sambrook et al
> (a.k.a. the "Maniatis") it says not to use TRIZMA for SDS PAGE
> electrophoresis buffers but Tris Base which should be pH'd to the
> appropriate pH instead of using a mixture of Trisbase and Tris-HCl. Does
> anyone know the reason for this.
But I thought Tris base and Trizma were the same. The compound used for
electrophoresis is tris(hydroxymethyl)aminomethane which, from Sigma,
comes as TRIZMA (base). The TrisHCl is simply the hydrocloride of the
above and is extremely acidic. I have known first time research students
to use this TrisHCl only to be thrown off by pH of the buffer. The mistake
is in writing. Some people prefer to write Tris.HCl (pH X.Y) in their
recipes, indicating that the specified pH was obtained by titrating with
HCl. The resultant compound is a chloride salt and not hydrochloride. I
prefer writing Tris.Cl, to avoid confusion.
I have never come across any protocol where the Tris buffer is
prepared by mixing Tris base and hydrochloride to obtain a specific pH. I
am not sure what the authors in Sambrook et al. meant, but I will not be
surprised if it is a mistake. There are a few very obvious yet serious
mistakes in that manual. The question is that whether, by using Trizma
base, anybody has encountered any problem in SDS-PAGE!
Hiranya S. Roychowdhury
Plant Genetic Engineering Lab.
Box 3GL, NM State Univ.
Las Cruces, NM 88003
Phone: (505) 646-5785
hroychow at nmsu.edu
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