Finally, we constructed a physicochemical orthophosphate cycle incorporating both in situ formation of the KSTA imidazole phosphate and histidyl organocatalysis. The cycle starts in solution where orthophosphate is activated via a reaction with cyanate to form carbamoyl phosphate (Figure ). This then reacts with imidazole to form the KSTA imidazole phosphate which traps the activated phosphate in a kinetically stable state. The formation of imidazole phosphate enables the activated phosphate to enter into the histidyl peptide catalytic cycle. The phosphate is transferred from the imidazole phosphate to the imidazolyl of the histidyl peptide catalyst to form a phosphorylated histidyl intermediate. Upon drying the solution to a paste, where the activity of water is lower, this phosphorylated histidyl intermediate accelerates the phosphorylation of the prebiotically important organic nucleophiles, e.g. glycerol. Note that both the formation of imidazole phosphate and the phosphorylated histidyl intermediate are aided by the wet-to-dry transition due to the increasing concentrations of all reactants as the solvent water evaporates. To complete the cycle, the paste is redissolved in a cyanate solution which refuels the system. The remaining orthophosphate can then be converted into imidazole phosphate and later transferred onwards onto the organic nucleophile. Multiple passes through the physicochemical cycle lead to the accumulation of phosphorylated compounds.