The relative hydrolytic reactivities of pyrophosphites and pyrophosphates

Dharmit Mistry, Nicholas Powles

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The pH-rate profiles for the hydrolysis of pyrophosphate (PP(v)) and pyrophosphite (PP(iii), pyro-di-H-phosphonate) are a complex function of pH, reflecting the different ionic species and their relative reactivities. PP(iii) is more reactive than PP(v) at all pHs and only PP(iii) shows a hydroxide-ion reaction at high pH, so it is 1010-fold more reactive than PP(v) in 0.1 M NaOH. The pKa2 of PP(iii) ∼0.44, so the dominant species at pH's > 1 is the di-anion PP(iii)2-. Although there is no observable (NMR or ITC) binding of Mg2+ to the PP(iii) di-anion there is a modest increase in the rate of hydrolysis of PP(iii) by Mg2+. PP(iii) is neither a substrate nor an inhibitor of pyrophosphatase, the enzyme that efficiently catalyses the hydrolysis of PP(v).

Original languageEnglish
Pages (from-to)5727-5733
Number of pages7
JournalOrganic and Biomolecular Chemistry
Volume11
Issue number34
DOIs
Publication statusPublished - 14 Sep 2013

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Diphosphates
Hydrolysis
reactivity
hydrolysis
Anions
Pyrophosphatases
Organophosphonates
anions
Enzyme Inhibitors
Nuclear magnetic resonance
inhibitors
hydroxides
enzymes
Substrates
Enzymes
nuclear magnetic resonance
profiles
ions

Cite this

Mistry, Dharmit ; Powles, Nicholas. / The relative hydrolytic reactivities of pyrophosphites and pyrophosphates. In: Organic and Biomolecular Chemistry. 2013 ; Vol. 11, No. 34. pp. 5727-5733.
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The relative hydrolytic reactivities of pyrophosphites and pyrophosphates. / Mistry, Dharmit; Powles, Nicholas.

In: Organic and Biomolecular Chemistry, Vol. 11, No. 34, 14.09.2013, p. 5727-5733.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The relative hydrolytic reactivities of pyrophosphites and pyrophosphates

AU - Mistry, Dharmit

AU - Powles, Nicholas

PY - 2013/9/14

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AB - The pH-rate profiles for the hydrolysis of pyrophosphate (PP(v)) and pyrophosphite (PP(iii), pyro-di-H-phosphonate) are a complex function of pH, reflecting the different ionic species and their relative reactivities. PP(iii) is more reactive than PP(v) at all pHs and only PP(iii) shows a hydroxide-ion reaction at high pH, so it is 1010-fold more reactive than PP(v) in 0.1 M NaOH. The pKa2 of PP(iii) ∼0.44, so the dominant species at pH's > 1 is the di-anion PP(iii)2-. Although there is no observable (NMR or ITC) binding of Mg2+ to the PP(iii) di-anion there is a modest increase in the rate of hydrolysis of PP(iii) by Mg2+. PP(iii) is neither a substrate nor an inhibitor of pyrophosphatase, the enzyme that efficiently catalyses the hydrolysis of PP(v).

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