KEGG   ENZYME: 1.1.1.236Help
Entry
EC 1.1.1.236                Enzyme                                 

Name
tropinone reductase II;
tropinone (psi-tropine-forming) reductase;
pseudotropine forming tropinone reductase;
tropinone reductase (ambiguous);
TR-II
Class
Oxidoreductases;
Acting on the CH-OH group of donors;
With NAD+ or NADP+ as acceptor
BRITE hierarchy
Sysname
pseudotropine:NADP+ 3-oxidoreductase
Reaction(IUBMB)
pseudotropine + NADP+ = tropinone + NADPH + H+ [RN:R06734]
Reaction(KEGG)
Substrate
pseudotropine [CPD:C02066];
NADP+ [CPD:C00006]
Product
tropinone [CPD:C00783];
NADPH [CPD:C00005];
H+ [CPD:C00080]
Comment
This enzyme along with EC 1.1.1.206, tropine dehydrogenase, represents a branch point in tropane alkaloid metabolism [3]. Tropine (the product of EC 1.1.1.206) is incorporated into hyoscyamine and scopolamine whereas pseudotropine (the product of EC 1.1.1.236) is the first specific metabolite on the pathway to the calystegines [3]. Both enzymes are always found together in any given tropane-alkaloid-producing species, have a common substrate, tropinone, and are strictly stereospecific [2].
History
EC 1.1.1.236 created 1992, modified 2007
Pathway
Tropane, piperidine and pyridine alkaloid biosynthesis
Orthology
K05354  
tropinone reductase II
Genes
SLY: 
SOT: 
102589607(TRII)
Taxonomy
Reference
1
  Authors
Drager, B., Hashimoto, T. and Yamada, Y.
  Title
Purification and characterization of pseudotropine forming tropinone reductase from Hyoscyamus niger root cultures.
  Journal
Agric. Biol. Chem. 52 (1988) 2663-2667.
Reference
2
  Authors
Couladis, M.M, Friesen, J.B., Landgrebe, M.E. and Leete, E.
  Title
Enzymes catalysing the reduction of tropinone to tropine and psi-tropine isolated from the roots of Datura innoxia.
  Journal
Pytochemistry 30 (1991) 801-805.
Reference
3  [PMID:8415746]
  Authors
Nakajima K, Hashimoto T, Yamada Y.
  Title
Two tropinone reductases with different stereospecificities are short-chain dehydrogenases evolved from a common ancestor.
  Journal
Proc. Natl. Acad. Sci. U. S. A. 90 (1993) 9591-5.
  Sequence
Reference
4  [PMID:16426652]
  Authors
Drager B.
  Title
Tropinone reductases, enzymes at the branch point of tropane alkaloid metabolism.
  Journal
Phytochemistry. 67 (2006) 327-37.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
136111-61-0

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