Inorganic pyrophosphatase

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inorganic pyrophosphatase
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Soluble inorganic pyrophosphatase
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Chr. 10 q11.1-q24
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Inorganic pyrophosphatase (or inorganic diphosphatase, PPase) is an

biochemical transformations.[6][7]

Two types of

proton-pumping pyrophosphatases (sPPases and H(+)-PPases, respectively). sPPases are ubiquitous proteins that hydrolyse pyrophosphate to release heat, whereas H+-PPases, so far unidentified in animal and fungal cells, couple the energy of PPi hydrolysis to proton movement across biological membranes.[8][9]

Structure

Thermostable soluble pyrophosphatase had been isolated from the

oligomeric organization (Image 1).[10]

Humans possess two genes encoding pyrophosphatase, PPA1 and PPA2.

gene locus on human chromosome 10,[12] and PPA2 to chromosome 4.[13]

Mechanism

Though the precise mechanism of catalysis via inorganic pyrophosphatase in most organisms remains uncertain, site-directed mutagenesis studies in Escherichia coli have allowed for analysis of the enzyme active site and identification of key amino acids. In particular, this analysis has revealed 17 residues of that may be of functional importance in catalysis.[14]

Further research suggests that the

nucleophilic attack.[14]

Several studies have also identified additional

allosteric activator in Escherichia coli,[16] while fluoride has been shown to inhibit hydrolysis of pyrophosphate in yeast.[17]

Biological function and significance

The hydrolysis of inorganic

exergonic (accounting for approximately a −19kJ change in free energy), and therefore greatly increases the energetic favorability of reaction system when coupled with a typically less-favorable reaction.[19]

Inorganic pyrophosphatase catalyzes this

fatty acids destined for beta oxidation.[19]

Before

inorganic phosphate
used in other biological processes.

Evolution

Examination of

Gly, Ala, Val and Asp, suggesting an evolutionarily ancient origin for the protein.[21]

References

  1. PMID 5342521
    .
  2. PMID 11401820
    .
  3. PMID 4327778
    .
  4. PMID 16181808
    .
  5. ISBN 1-57259-153-6
    .
  6. S2CID 40325661
    .
  7. S2CID 44916855
    .
  8. PMID 12451180
    .
  9. S2CID 12452334
    .
  10. PMID 7920256
    .
  11. PMID 10542310
    .
  12. PMID 975879
    .
  13. ^ "PPA2 pyrophosphatase (inorganic) 2 [Homo sapiens (human)]". NCBI Gene.
  14. ^
    PMID 19366250
    .
  15. S2CID 19512830
    .
  16. S2CID 21045503
    .
  17. PMID 6139128
    .
  18. PMID 15522220
    .
  19. ^
    PMID 17079146
    .
  20. PMID 1323891
    .
  21. S2CID 5718374
    .

External links

Further reading
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