Editing Polyphosphate (section)

== Acid-base and complexation properties ==
Polyphosphates are [[Base (chemistry)|weak base]]s. A lone pair of electrons on an oxygen atom can be donated to a [[hydrogen ion]] (proton) or a metal ion in a typical [[Lewis acid]]-[[Lewis base]] interaction. This has profound significance in biology. For instance, adenosine triphosphate is  about 25% protonated in aqueous solution at pH&nbsp;7.<ref name=Storer>{{cite journal|author-link2=Athel Cornish-Bowden|vauthors=Storer A, Cornish-Bowden A | title = Concentration of MgATP2- and other ions in solution. Calculation of the true concentrations of species present in mixtures of associating ions | pmc=1164030 | journal = Biochem J | volume = 159 | issue = 1 | pages = 1–5 | year = 1976 | pmid = 11772 | doi=10.1042/bj1590001}}</ref> 
:ATP<sup>4−</sup> + H<sup>+</sup> {{eqm}} ATPH<sup>3−</sup>, p''K''<sub>a</sub> <math>\approx</math> 6.6
Further protonation occurs at lower pH&nbsp;values.