To demonstrate this physicochemical orthophosphate cycle with histidyl organocatalysis, we prepared solutions of 20 mM sodium phosphate, 230 mM potassium cyanate and 100 M imidazole with 500 mM glycerol nucleophile, in both the presence and absence of 100 mM histidyl catalyst at pH 7.3 and 22 °C (SI Section S4). The solutions were left for 24 h in order to allow carbamoyl phosphate and imidazole phosphate to accumulate. To facilitate the histidyl catalysed phosphate transfer to glycerol, we dried the solutions down into paste by leaving them to evaporate in the open air for 48 h at 22 °C. To demonstrate that this cycle could function repeatedly, we dissolved the paste back into 100 mM potassium cyanate solution at pH 7.3 and then repeated the aforementioned procedure.