Figure 1.

Schematic overview of purine and pyrimidine metabolism. Ribose-5-phosphate and carbamoyl-phosphate are the starting points of purine and pyrimidine biosynthetic pathways, respectively. Key intermediates, across de novo biosynthesis and salvage pathways, are highlighted in gray boxes. End-products of purine and pyrimidine catabolism (i.e., uric acid and β-alanine) are in white boxes. Enzymes discussed in the manuscript are depicted in red. PRPP, 5-phosphorybosyl-1-pyrophosphate; OPRT, orotate phosphoribosyltransfrase, PrsA, PRPP synthetase; S-AMP, adenylosuccinate; SAICAR: succinylaminoimidazole carboxamide ribotide.