Tris
From Wikipedia, the free encyclopedia
| Tris | |
|---|---|
 |
|
| IUPAC name | 2-Amino-2-hydroxymethyl-propane-1,3-diol |
| Other names | TRIS, Tris, Tris base, Tris buffer, TrizmaTM, Trisamine, THAM, Tromethamine, Trometamol, Tromethane |
| Identifiers | |
| CAS number | [77-86-1] |
| RTECS number | TY2900000 |
| SMILES | C(C(CO)(CO)N)O |
| Properties | |
| Molecular formula | C4H11NO3 |
| Molar mass | 121.14 g mol-1 |
| Appearance | White crystalline powder |
| Melting point |
>175-176°C (448-449 K) |
| Boiling point |
219°C (492 K) |
| Solubility in water | 220 g/100 ml (20°C) in water |
| Acidity (pKa) | 8.1 |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritant |
| NFPA 704 |
 0
2
0
|
| R-phrases | R36, R37, R38. |
| S-phrases | S26, S36. |
| Flash point | Non-flammable |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
|
Tris is an abbreviation of the organic compound known as tris(hydroxymethyl)aminomethane, with the formula (HOCH2)3CNH2. Tris is extensively used in biochemistry and molecular biology.[1] In biochemistry, tris is widely used as a component of buffer solutions, such as in TAE and TBE buffer, especially for solutions of nucleic acids. It is a primary amine and thus undergoes the reactions associated with typical amines, e.g. condensations with aldehydes.
Contents |
[edit] Buffering features
Tris has a pKa of 8.3 (at 20 °C), which implies that the buffer has an effective pH range between 7.0 and 9.2. Being slightly basic, tris forms an effective buffer for slightly basic solutions, which keeps DNA deprotonated and soluble in water. Tris is commonly combined with EDTA to make "TE buffer" for stabilization and storage of DNA. EDTA binds to magnesium (Mg2+), which is a co-factor for many DNA-modifying enzymes. More importantly, however, EDTA has a stronger affinity for iron ions, which are often trace contaminants in magnesium, and which can react with DNA. Thus only a small amount of EDTA is typically added, most of which binds to magnesium and reduces the effective magnesium concentration, but it also functions to protect the DNA from being cut by iron.
[edit] Buffer details
Because of the widespread use of tris buffers, detailed information on its use is available. Some features:
- The pKa declines approximately 0.03 units per degree Celsius rise in temperature.
- Tris reacts strongly with pH electrodes.[citation needed]
- It is toxic to mammalian cells.
[edit] Preparation
Tris is prepared in two steps from nitromethane via the intermediate (HOCH2)3CNO2 . Reduction of the latter gives tris(hydroxymethyl)aminomethane.[2]
[edit] Uses
Tris has been used in protein crystallization at various pH values.[3] Low-ionic strength tris buffers in the formation of intermediate filaments of lamin from C. elegans has been described. The use of tris in both capillary electrochromatography and UV analysis of tocopherols and tocotrienols has been documented.[4] Tris is also used as an intermediate for the preparation of surface active agents, vulcanization accelerators, and pharmaceuticals, and used as a titrimetric standard.
It is also used in SDS-PAGE
[edit] References
- ^ Gomori, G., Preparation of Buffers for Use in Enzyme Studies. Methods Enzymology., 1, 138-146 (1955).
- ^ Sheldon B. Markofsky “Nitro Compounds, Aliphatic” Ullmann's Encyclopedia of Industrial Chemistry 2002 by Wiley-VCH, Wienheim, 2002. DOI: 10.1002/14356007.a17_401.
- ^ Campos, A., et al., Crystallization and preliminary X-ray analysis of FlhD from Escherichia coli. J. Struct. Biol., 123(3), 269-271 (1988).
- ^ Abidi, S.L., and Rennink, K.A., Capillary electrochromatographic evaluation of vitamin E-active oil constituents: tocopherols and tocotrienols. J. Chromatogr. A, 913(1-2), 379-386 (2001).
