The Role of Pyrophosphate in the Origin of Life: An Energy-Based Hypothesis.

Life could not emerge through molecular synthesis alone; it also required mechanisms that coupled environmental energy to directional chemical change. Yet, ATP, the dominant energy carrier in modern cells, depends on nucleotide synthesis, selective catalysis, and membrane-based regeneration, making it an unlikely starting point for bioenergetics. Here, I examine inorganic pyrophosphate as a possible intermediate between geochemical phosphate activation and ATP-centred metabolism. Condensed phosphates can form under plausible volcanic, mineral-mediated, and wet-dry conditions, and pyrophosphate has sufficient transfer potential to support selected phosphorylation reactions and ion translocation when appropriately coupled. I propose that recurrent pyrophosphate production could have promoted the formation of phosphorylated sugars, linking prebiotic carbon synthesis to non-enzymatic reaction networks resembling central metabolism. Activated enol and acyl phosphates may subsequently have regenerated pyrophosphate, allowing partial energetic closure. I further consider how polyphosphorylated pentoses could have provided transitional group-transfer scaffolds from which nucleotide-based activation chemistry emerged. In this view, ATP did not replace an unrelated primordial currency, but consolidated functions already distributed across simpler phosphate compounds. The persistence of pyrophosphate in biosynthetic directionality, phosphoryl transfer, and membrane energetics may therefore reflect a remnant of an earlier energetic architecture.