A Nonenzymatic Analogue of the Biosynthesis of Pyridoxal Vitamers

Coenzymes such as the pyridoxal vitamers promote their native reactions in the absence of enzymes and may therefore have played an early role in the emergence of metabolism. However, it is still unclear whether coenzymes could have been produced nonenzymatically according to their biosynthetic pathways. Here, we show a nonenzymatic analogue of pyridoxal vitamer biosynthesis that occurs in milliseconds when a dilute aqueous solution of ammonia and the triose and pentose phosphates used by the biological pathway is electrosprayed to produce charged droplets exhibiting strong interfacial electric fields. Pyridoxal vitamers were not observed when both sugars lacked phosphoryl groups, suggesting the importance of phosphoryl groups in the enzymatic pathway also extends to analogous nonenzymatic chemistry. Pyridoxal coenzyme biosynthesis joins a growing body of evidence showing that nonenzymatic precursors to metabolic pathways could have initiated in environments containing electric fields of a similar strength to those found in enzymes.