Synthesis and Breakdown of the Universal Precursors to Biological Metabolism Promoted by Ferrous Iron

How core biological metabolism initiated and why it uses the intermediates, reactions and pathways that it does remains unclear. Life builds its molecules from CO<sub>2 </sub>and breaks them down to CO<sub>2 </sub>again through the intermediacy of just five metabolites that act as the hubs of biochemistry. Here, we describe a purely chemical reaction network promoted by Fe<sup>2+ </sup>in which aqueous pyruvate and glyoxylate, two products of abiotic CO<sub>2 </sub>reduction, build up nine of the eleven TCA cycle intermediates, including all five universal metabolic precursors. The intermediates simultaneously break down to CO<sub>2 </sub>in a life-like regime resembling biological anabolism and catabolism. Introduction of hydroxylamine and Fe<sup>0 </sup>produces four biological amino acids. The network significantly overlaps the TCA/rTCA and glyoxylate cycles and may represent a prebiotic precursor to these core metabolic pathways.