Difference between revisions of "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. HEPES is often used to maintain protein solubility in biochemical experiments.
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A ''Good'' buffer [Good'66 PMID 5942950, Good'74 PMID 4206745, Blanchard'84 PMID 6717292].  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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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.
 
<biblio>
 
# Good66 pmid=5942950
 
# Good74 pmid=4206745
 
# Blanchard84 pmid=6717292
 
</biblio>
 
  
  
 
[[Category:Material]] and [[Category:Buffers]]
 
[[Category:Material]] and [[Category:Buffers]]

Revision as of 07:30, 2 November 2011

N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9

A Good buffer [Good'66 PMID 5942950, Good'74 PMID 4206745, Blanchard'84 PMID 6717292]. 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. and