Tris
| Tris | |
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2-Amino-2-hydroxymethyl-propane-1,3-diol |
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Other names
TRIS, Tris, Tris base, Tris buffer, |
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| Identifiers | |
| CAS number | 77-86-1  |
| PubChem | 6503 |
| ChemSpider | 6257 |
| UNII | 023C2WHX2V |
| KEGG | D00396 |
| ChEBI | CHEBI:9754 |
| ChEMBL | CHEMBL1200391  |
| RTECS number | TY2900000 |
| ATC code | B05,B05XX02 |
| Jmol-3D images | Image 1 |
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| 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, 426 °F |
| Solubility in water | ~50 g/100 mL (25 °C) |
| Acidity (pKa) | 8.07 |
| Hazards | |
| MSDS | External MSDS |
| R-phrases | R36 R37 R38 |
| S-phrases | S26 S36 |
| Main hazards | Irritant |
| NFPA 704 |
 0
2
0
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| Flash point | Non-flammable |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Tris (also known as THAM) 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.
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[edit] Buffering features
Tris has a pKa of 8.06 at 25°C , which implies that the buffer has an effective pH range between 7.1 and 9.0.
[edit] Buffer details
- The pKa declines approximately 0.03 units per degree Celsius rise in temperature.[2][3]
- Silver-containing single-junction pH electrodes (e.g., silver chloride electrode) are incompatible with Tris (Ag-tris precipitation clogs the junction). Double-junction electrodes are resistant to this problem, and non-silver containing electrodes are immune.
- A common form of tris is tris-HCl, which is the acid salt. When titrated to when pH = pKa with the corresponding counterion (OH- for tris-HCl, H+ for tris base) they have equivalent concentrations. However, the molecular weights are different and must be correctly accounted for in order to arrive at the expected buffer strength.
[edit] Buffer inhibition
- It is reported that Tris inhibits a number of enzymes,[4][5] and therefore, it should be used with care when studying proteins.
[edit] Preparation
Tris is prepared in two steps from nitromethane via the intermediate (HOCH2)3CNO2. Reduction of the latter gives tris(hydroxymethyl)aminomethane.[6]
[edit] Uses
The useful buffer range for tris (7-9) coincides with the typical physiological pH of most living organisms. This, and its low cost, make tris one of the most common buffers used in the biology/biochemistry lab. Tris is also used as a primary standard to standardize acid solutions for chemical analysis.
[edit] Medical
Tris (usually known as THAM in this context) is used as alternative to sodium bicarbonate in the treatment of metabolic acidosis.[7]
[edit] See also
[edit] References
- ^ Gomori, G., Preparation of Buffers for Use in Enzyme Studies. Methods Enzymology., 1, 138-146 (1955).
- ^ El-Harakany, A.A.; Abdel Halima, F.M. and Barakat, A.O. (1984). "Dissociation constants and related thermodynamic quantities of the protonated acid form of tris-(hydroxymethyl)-aminomethane in mixtures of 2-methoxyethanol and water at different temperatures". J. Electroanal. Chem. 162 (1–2): 285–305. doi:10.1016/S0022-0728(84)80171-0.
- ^ Vega, C.A.; Butler, R.A. et al. (1985). "Thermodynamics of the Dissociation of Protonated Tris(hydroxymethy1)aminomethane in 25 and 50 wt % 2-Propanol from 5 to 45 °C". J. Chem. Eng. Data 30 (4): 376–379. doi:10.1021/je00042a003.
- ^ Desmarais, WT; et al. (2002). "The 1.20 Å resolution crystal structure of the aminopeptidase from Aeromonas proteolytica complexed with Tris: A tale of buffer inhibition". Structure 10 (8): 1063–1072. doi:10.1016/S0969-2126(02)00810-9. PMID 12176384.
- ^ Ghalanbor, Z; et al. (2008). "Binding of Tris to Bacillus licheniformis alpha-amylase can affect its starch hydrolysis activity". Protein Peptide Lett. 15 (2): 212–214. doi:10.2174/092986608783489616. PMID 18289113.
- ^ Markofsky, Sheldon B. (2000). Nitro Compounds, Aliphatic. doi:10.1002/14356007.a17_401.
- ^ Kallet, RH; Jasmer RM, Luce JM et al. (2000). "The treatment of acidosis in acute lung injury with tris-hydroxymethyl aminomethane (THAM)". American Journal of Respiratory and Critical Care Medicine 161 (4): 1149–1153. PMID 10764304.
