Quinolinate synthase

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = Quinolinate synthase

| EC_number = 2.5.1.72

| CAS_number =

| GO_code =

| image =

| width =

| caption =

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Quinolinate synthase ({{EC number|2.5.1.72}}, NadA, QS, quinolinate synthetase) is an enzyme with systematic name glycerone phosphate:iminosuccinate alkyltransferase (cyclizing).{{cite journal | vauthors = Ollagnier-de Choudens S, Loiseau L, Sanakis Y, Barras F, Fontecave M | title = Quinolinate synthetase, an iron-sulfur enzyme in NAD biosynthesis | journal = FEBS Letters | volume = 579 | issue = 17 | pages = 3737–43 | date = July 2005 | pmid = 15967443 | doi = 10.1016/j.febslet.2005.05.065 | url = https://hal.archives-ouvertes.fr/hal-00374522/file/NadAFEBS2.pdf | doi-access = free }}{{cite journal | vauthors = Katoh A, Uenohara K, Akita M, Hashimoto T | title = Early steps in the biosynthesis of NAD in Arabidopsis start with aspartate and occur in the plastid | journal = Plant Physiology | volume = 141 | issue = 3 | pages = 851–7 | date = July 2006 | pmid = 16698895 | pmc = 1489895 | doi = 10.1104/pp.106.081091 }}{{cite journal | vauthors = Sakuraba H, Tsuge H, Yoneda K, Katunuma N, Ohshima T | title = Crystal structure of the NAD biosynthetic enzyme quinolinate synthase | journal = The Journal of Biological Chemistry | volume = 280 | issue = 29 | pages = 26645–8 | date = July 2005 | pmid = 15937336 | doi = 10.1074/jbc.C500192200 | doi-access = free }}{{cite journal | vauthors = Rousset C, Fontecave M, Ollagnier de Choudens S | title = The [4Fe-4S] cluster of quinolinate synthase from Escherichia coli: investigation of cluster ligands | journal = FEBS Letters | volume = 582 | issue = 19 | pages = 2937–44 | date = August 2008 | pmid = 18674537 | doi = 10.1016/j.febslet.2008.07.032 | doi-access = free }}{{cite journal | vauthors = Saunders AH, Booker SJ | title = Regulation of the activity of Escherichia coli quinolinate synthase by reversible disulfide-bond formation | journal = Biochemistry | volume = 47 | issue = 33 | pages = 8467–9 | date = August 2008 | pmid = 18651751 | pmc = 3319134 | doi = 10.1021/bi801135y }} This enzyme catalyses the following chemical reaction

: glycerone phosphate + iminosuccinate $\backslash rightleftharpoons$ pyridine-2,3-dicarboxylate + 2 H₂O + phosphate

This iron-sulfur protein that requires a [4Fe-4S] cluster for activity.