:Carboxynorspermidine synthase

{{Infobox enzyme

| Name = Carboxynorspermidine synthase

| EC_number = 1.5.1.43

| CAS_number =

| GO_code =

| image =

| width =

| caption =

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Carboxynorspermidine synthase ({{EC number|1.5.1.43}}, carboxynorspermidine dehydrogenase, carboxyspermidine dehydrogenase, CASDH, CANSDH) is an enzyme with systematic name carboxynorspermidine:NADP⁺ oxidoreductase.{{cite journal | vauthors = Nakao H, Shinoda S, Yamamoto S | title = Purification and some properties of carboxynorspermidine synthase participating in a novel biosynthetic pathway for norspermidine in Vibrio alginolyticus | journal = Journal of General Microbiology | volume = 137 | issue = 7 | pages = 1737–42 | date = July 1991 | pmid = 1955861 | doi = 10.1099/00221287-137-7-1737 | doi-access = free }}{{cite journal | vauthors = Lee J, Sperandio V, Frantz DE, Longgood J, Camilli A, Phillips MA, Michael AJ | title = An alternative polyamine biosynthetic pathway is widespread in bacteria and essential for biofilm formation in Vibrio cholerae | journal = The Journal of Biological Chemistry | volume = 284 | issue = 15 | pages = 9899–907 | date = April 2009 | pmid = 19196710 | pmc = 2665113 | doi = 10.1074/jbc.M900110200 | doi-access = free }}{{cite journal | vauthors = Hanfrey CC, Pearson BM, Hazeldine S, Lee J, Gaskin DJ, Woster PM, Phillips MA, Michael AJ | title = Alternative spermidine biosynthetic route is critical for growth of Campylobacter jejuni and is the dominant polyamine pathway in human gut microbiota | journal = The Journal of Biological Chemistry | volume = 286 | issue = 50 | pages = 43301–12 | date = December 2011 | pmid = 22025614 | pmc = 3234850 | doi = 10.1074/jbc.M111.307835 | doi-access = free }} This enzyme catalyses the following chemical reactions

: (1) carboxynorspermidine + H₂O + NADP⁺ $\backslash rightleftharpoons$ L-aspartate 4-semialdehyde + propane-1,3-diamine + NADPH + H⁺

: (2) carboxyspermidine + H₂O + NADP⁺ $\backslash rightleftharpoons$ L-aspartate 4-semialdehyde + putrescine + NADPH + H⁺

The reaction takes place in the opposite direction.