Polarizable proton-transfer hydrogen bonds between phosphate and organic acids. Implications for the mechanism of biological calcification

Abstract

Proton-transfer equilibria COH⋯O^–P ⇌ CO^–⋯HOP involving hydrogen bonds between HPO^2–₄ and organic acids containing COOH and phenolic OH groups have been studied by i.r. spectroscopy. These hydrogen bonds show a large proton polarizability and consequently the protons within them can easily be translocated by local electric fields. This suggests that the acidic proteins involved in bone calcification may act not only by supplying Ca²⁺ ions but also by removing protons.