Using Tris Buffer in Biochemistry and Molecular Biology Experiments

Biochemistry, Molecular Biology, and Cell Biology Protocols  >> Using Tris Buffer in Biochemistry and Molecular Biology Experiments

Note:  Tris contains a free amine group, and should not be used in reactions where a free amine group would interfere with the reaction (eg NHS-Biotin reactions).

The simplest way to use Tris for biochemistry and molecular biology experiments is to first make a 1M solution:

1M Tris, pH 7.4

1. Weigh 121.1 g Tris in 700 ml double distilled water
2. Do not start with too much water; otherwise, the volume after pHing may be too great
3. Start stirring, and then check the pH
4. With a 3M HCl solution, start to pH the solution such that the pH reaches 7.4
(Be careful not to inhale the HCl.)
5. Add with double distilled water up to 1L
6. Filter or autoclave if necessary
7. May be better to store at 4 degrees C
8. Dilute to appropriate concentration for use in biochemistry or molecular biology experiments.  20 mM or 50 mM Tris, pH 7.4 solutions are common.

Other Common Solutions Containing Tris:

50x TAE for running Agarose Gels

Tris 121g
EDTA 50mL 500mM (pH the EDTA to pH 8.0 with NaOH first before adding)
Acetic acid 28.55mL
Make up to 500mL
Make 1x TAE from 50x with water

TBS (Tris Buffered Saline) - such as for Western blots instead of using PBS

20 mM Tris, pH 7.4
150 mM NaCl

TE (Tris EDTA) buffer - such as for preparing membrane fractions

10 mM Tris, pH 7.4
  2 mM EDTA

Some protocols may use Tris at other pHs - usually between 6.8 and 8.8.  Other buffers such as Bis-Tris, MES, BES, or PIPES may be suitable for other pH ranges.

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