Scalable Chemoenzymatic Synthesis of Inositol Pyrophosphates

Abstract

The inositol pyrophosphates (PP-InsPs) are an important group of cellular messengers that influence a broad range of biological processes. To elucidate the functions of these high-energy metabolites at the biochemical level, access to the purified molecules is required. Here, a robust and scalable strategy for the synthesis of various PP-InsPs [5PP-InsP₅, 1PP-InsP₅, and 1,5(PP)₂-InsP₄] is reported, relying on the highly active inositol hexakisphosphate kinase A from <i>Entamoeba histolytica</i> and the kinase domain of human diphosphoinositol pentakisphosphate kinase 2. A facile purification procedure using precipitation with Mg²⁺ ions and an optional strong anion exchange chromatography on an FPLC system afforded PP-InsPs in high purity. Furthermore, the newly developed protocol could be applied to simplify the synthesis of radiolabeled 5PP-InsP₅-β³²P, which is a valuable tool for studying protein pyrophosphorylation. The chemoenzymatic method for obtaining PP-InsPs is readily amenable to both chemists and biologists and will thus foster future research on the multiple signaling functions of PP-InsP molecules.