Evidence in vitro for an enzymatic synthesis of phosphocitrate.

A biological synthesis of phosphocitrate is described from precursors, citrate and adenosinetriphosphate reacting in the presence of rat liver homogenate. Identity of the newly formed product was examined by enzymatic digestion of reactions mixtures, HPLC chromatography and 1H-NMR spectra. Authenticity of product was established by comparison to chemically synthesized phosphocitrate. Recognition of the existence of a biologically synthetic pathway adds credence to the known presence of phosphocitrate in mitochondria and a postulated role to control calcium phosphate deposition in that organelle.