Encyclopedia > Pyrophosphate

  Article Content

Pyrophosphate

Pyrophosphate, or PPi is an anion observed in living systems, usually formed by the hydrolysis of ATP into AMP.

  • ATP → AMP + PPi

The pyrophosphate anion has the structure P2O74-, and is an acid anhydride[?] of phosphate. It is unstable in aqueous solution and rapidly hydrolyzes[?] into inorganic phosphate:

  • P2O74- + H2O → 2 HPO42-

or in shorthand notation:

  • PPi + H2O → 2 Pi

This hydrolysis to inorganic phosphate effectively renders the hydrolysis of ATP to AMP and PPi 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 cost 2 high energy phosphates, as to reconstitute AMP from ATP will require 2 phosphorylation reactions.

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



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Thomas a Kempis

... character and include tracts and meditations, letters, sermons, a life of Saint Lydewigis[?], a Christian woman who remained steadfast under a great stress o ...

 
 
 
This page was created in 23.5 ms