Prometabolites of 5‐Diphospho‐myo‐inositol Pentakisphosphate

Diphospho‐myo‐inositol phosphates (PP‐InsP_y) are an important class of cellular messengers. Thus far, no method for the transport of PP‐InsP_y into living cells is available. Owing to their high negative charge density, PP‐InsP_y will not cross the cell membrane. A strategy to circumvent this issue involves the generation of precursors in which the negative charges are masked with biolabile groups. A PP‐InsP_y prometabolite would require twelve to thirteen biolabile groups, which need to be cleaved by cellular enzymes to release the parent molecules. Such densely modified prometabolites of phosphate esters and anhydrides have never been reported to date. This study discloses the synthesis of such agents and an analysis of their metabolism in tissue homogenates by gel electrophoresis. The acetoxybenzyl‐protected system is capable of releasing 5‐PP‐InsP₅ in mammalian cell/tissue homogenates within a few minutes and can be used to release 5‐PP‐InsP₅ inside cells. These molecules will serve as a platform for the development of fundamental tools required to study PP‐InsP_y physiology.