Pyrophosphate

Revision as of 18:49, 21 April 2009 by Marshallsumter (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

WikiDoc Resources for Pyrophosphate

Articles

Most recent articles on Pyrophosphate

Most cited articles on Pyrophosphate

Review articles on Pyrophosphate

Articles on Pyrophosphate in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Pyrophosphate

Images of Pyrophosphate

Photos of Pyrophosphate

Podcasts & MP3s on Pyrophosphate

Videos on Pyrophosphate

Evidence Based Medicine

Cochrane Collaboration on Pyrophosphate

Bandolier on Pyrophosphate

TRIP on Pyrophosphate

Clinical Trials

Ongoing Trials on Pyrophosphate at Clinical Trials.gov

Trial results on Pyrophosphate

Clinical Trials on Pyrophosphate at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Pyrophosphate

NICE Guidance on Pyrophosphate

NHS PRODIGY Guidance

FDA on Pyrophosphate

CDC on Pyrophosphate

Books

Books on Pyrophosphate

News

Pyrophosphate in the news

Be alerted to news on Pyrophosphate

News trends on Pyrophosphate

Commentary

Blogs on Pyrophosphate

Definitions

Definitions of Pyrophosphate

Patient Resources / Community

Patient resources on Pyrophosphate

Discussion groups on Pyrophosphate

Patient Handouts on Pyrophosphate

Directions to Hospitals Treating Pyrophosphate

Risk calculators and risk factors for Pyrophosphate

Healthcare Provider Resources

Symptoms of Pyrophosphate

Causes & Risk Factors for Pyrophosphate

Diagnostic studies for Pyrophosphate

Treatment of Pyrophosphate

Continuing Medical Education (CME)

CME Programs on Pyrophosphate

International

Pyrophosphate en Espanol

Pyrophosphate en Francais

Business

Pyrophosphate in the Marketplace

Patents on Pyrophosphate

Experimental / Informatics

List of terms related to Pyrophosphate

Editor-In-Chief: Henry A. Hoff

File:Pyrophosphate-3D-balls.png
Ball-and-stick model of the pyrophosphate anion, P2O74−

In chemistry, the anion, the salts, and the esters of pyrophosphoric acid are called pyrophosphates. The anion P2O74− is abbreviated PPi and is formed by the hydrolysis of ATP into AMP in cells.

  • ATP → AMP + PPi

For example, when a nucleotide is incorporated into a growing DNA or RNA strand by a polymerase, pyrophosphate (PPi) is released. Pyrophosphorolysis is the reverse of the polymerization reaction where pyrophosphate reacts with the 3'-nucleotidemonophosphate (NMP or dNMP), which is removed from the oligonucleotide to release the corresponding triphosphate (dNTP from DNA, or NTP from RNA).

The pyrophosphate anion has the structure P2O74−, and is an acid anhydride of phosphate. It is unstable in aqueous solution and in the absence of enzymic catalysis hydrolyzes extremely slowly into inorganic phosphate in all but highly acidic media:[1]

  • P2O74− + H2O <=> 2 HPO42−

or in shorthand notation:

  • PPi + H2O <=> 2 Pi

Enzyme EC 3.6.1.1 catalyzes this hydrolysis.[2] Specificity varies with the source and with the activating metal ion, e.g. Mg2+.[2]

This hydrolysis to inorganic phosphate effectively renders the cleavage of ATP to AMP and PPi ultimately irreversible, and biochemical reactions coupled to this hydrolysis are irreversible as well.

From the standpoint of high energy phosphate accounting, the hydrolysis of ATP to AMP and PPi will require two high energy phosphates, as to reconstitute AMP into ATP will require two phosphorylation reactions.

  • AMP + ATP → 2 ADP
  • 2 ADP + 2 Pi → 2 ATP

The synthesis of tetraethyl pyrophosphate was first described in 1854 by Philip de Clermount at a meeting of the French Academy of Sciences.

The term pyrophosphate is also the name of esters formed by the condensation of a phosphorylated biological compound with inorganic phosphate as for dimethylallyl pyrophosphate. This bond is also referred to as a high energy phosphate bond.

References

  1. Huebner PWA, Milburn RM (1980). "Hydrolysis of pyrophosphate to orthophosphate promoted by cobalt(III). Evidence for the role of polynuclear species". Inorg Chem. 19 (5): 1267–72. doi:10.1021/ic50207a032. Unknown parameter |month= ignored (help)
  2. 2.0 2.1 "NiceZyme View of ENZYME: EC 3.6.1.1".

See also

External links

de:Diphosphate