Development of isotope-enriched phosphatidylinositol-4- and 5-phosphate cellular mass spectrometry probes.

Synthetic phosphatidylinositol phosphate (PtdIns ) derivatives play a pivotal role in broadening our understanding of PtdIns metabolism. However, the development of such tools is reliant on efficient enantioselective and regioselective synthetic strategies. Here we report the development of a divergent synthetic route applicable to the synthesis of deuterated PtdIns4 and PtdIns5 derivatives. The synthetic strategy developed involves a key enzymatic desymmetrisation step using Lipozyme TL-IM®. In addition, we optimised the large-scale synthesis of deuterated -inositol, allowing for the preparation of a series of saturated and unsaturated deuterated PtdIns4 and PtdIns5 derivatives. Experiments in MCF7 cells demonstrated that these deuterated probes enable quantification of the corresponding endogenous phospholipids in a cellular setting. Overall, these deuterated probes will be powerful tools to help improve our understanding of the role played by PtdIns in physiology and disease.