HEPES
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N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9 | N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9 | ||
| - | A Good buffer <cite>Good66</cite><cite>Good74</cite><cite>Blanchard84</cite>. Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range. | + | A Good buffer <cite>Good66</cite><cite>Good74</cite><cite>Blanchard84</cite>. Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range. HEPES is often used to maintain protein solubility in biochemical experiments. |
* pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C) | * pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C) | ||
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* molecular weight 238.3 | * molecular weight 238.3 | ||
* ΔpK<sub>a</sub>/ΔT = -.014 | * ΔpK<sub>a</sub>/ΔT = -.014 | ||
| - | *HEPES contains tertiary amines, which are reactive under certain conditions. See | + | * HEPES contains tertiary amines, which are reactive under certain conditions. |
| - | *Chemical formula: C<sub>8</sub>H<sub>18</sub>N<sub>2</sub>O<sub>4</sub>S | + | * See the structure of [http://store.p212121.com/products/HEPES-500-g.html HEPES]. |
| + | * Chemical formula: C<sub>8</sub>H<sub>18</sub>N<sub>2</sub>O<sub>4</sub>S | ||
Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. HEPES is essentially insoluble until it is neutralized. | Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. HEPES is essentially insoluble until it is neutralized. | ||
Revision as of 00:19, 31 July 2010
N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9
A Good buffer [1][2][3]. Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range. HEPES is often used to maintain protein solubility in biochemical experiments.
- pKa at 25C of 7.55 (7.31 at 37C)
- a second pKa at pH 3 is not of interest
- usable buffering range of 6.8 to 8.2
- molecular weight 238.3
- ΔpKa/ΔT = -.014
- HEPES contains tertiary amines, which are reactive under certain conditions.
- See the structure of HEPES.
- Chemical formula: C8H18N2O4S
Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. HEPES is essentially insoluble until it is neutralized.
- Good NE, Winget GD, Winter W, Connolly TN, Izawa S, and Singh RM. . pmid:5942950.
- Good NE and Izawa S. . pmid:4206745.
- Blanchard JS. . pmid:6717292.
