Dual Activity of Quinolinate Synthase: Triose Phosphate Isomerase and Dehydration Activities Play Together To Form Quinolinate Debora Reichmann Yohann CouteĢ Sandrine Ollagnier de Choudens 10.1021/acs.biochem.5b00991.s001 https://acs.figshare.com/articles/journal_contribution/Dual_Activity_of_Quinolinate_Synthase_Triose_Phosphate_Isomerase_and_Dehydration_Activities_Play_Together_To_Form_Quinolinate/2117341 Quinolinate synthase (NadA) is an Fe<sub>4</sub>S<sub>4</sub> cluster-containing dehydrating enzyme involved in the synthesis of quinolinic acid (QA), the universal precursor of the essential coenzyme nicotinamide adenine dinucleotide. The reaction catalyzed by NadA is not well understood, and two mechanisms have been proposed in the literature that differ in the nature of the molecule (DHAP or G-3P) that condenses with iminoaspartate (IA) to form QA. In this article, using biochemical approaches, we demonstrate that DHAP is the triose that condenses with IA to form QA. The capacity of NadA to use G-3P is due to its previously unknown triose phosphate isomerase activity. 2015-10-27 00:00:00 Form QuinolinateQuinolinate synthase NadA Triose Phosphate Isomerase IA Dehydration Activities Play condense form QA triose phosphate isomerase activity 4S coenzyme nicotinamide adenine dinucleotide DHAP