KEGG   ORTHOLOGY: K05354
Entry
K05354                      KO                                     
Symbol
TR2
Name
tropinone reductase II [EC:1.1.1.236]
Pathway
map00960  Tropane, piperidine and pyridine alkaloid biosynthesis
map01110  Biosynthesis of secondary metabolites
Reaction
R06734  pseudotropine:NADP+ 3-oxidoreductase
Brite
KEGG Orthology (KO) [BR:ko00001]
 09100 Metabolism
  09110 Biosynthesis of other secondary metabolites
   00960 Tropane, piperidine and pyridine alkaloid biosynthesis
    K05354  TR2; tropinone reductase II
Enzymes [BR:ko01000]
 1. Oxidoreductases
  1.1  Acting on the CH-OH group of donors
   1.1.1  With NAD+ or NADP+ as acceptor
    1.1.1.236  tropinone reductase II
     K05354  TR2; tropinone reductase II
Other DBs
GO: 0050358
Genes
SLY: 101256174
SPEN: 107018368
SOT: 102589607(TRII)
SSTN: 125856831
SDUL: 129871211
CANN: 107872392
LBB: 132615530 132615635 132615940
AG: AAA33282(TR2)
Reference
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 90:9591-5 (1993)
DOI:10.1073/pnas.90.20.9591
  Sequence
Reference
  Authors
Keiner R, Kaiser H, Nakajima K, Hashimoto T, Drager B
  Title
Molecular cloning, expression and characterization of tropinone reductase II, an enzyme of the SDR family in Solanum tuberosum (L.).
  Journal
Plant Mol Biol 48:299-308 (2002)
DOI:10.1023/A:1013315110746

KEGG   ENZYME: 1.1.1.236
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
Sysname
pseudotropine:NADP+ 3-oxidoreductase
Reaction(IUBMB)
pseudotropine + NADP+ = tropinone + NADPH + H+ [RN:R06734]
Reaction(KEGG)
R06734
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
ec00960  Tropane, piperidine and pyridine alkaloid biosynthesis
ec01110  Biosynthesis of secondary metabolites
Orthology
K05354  tropinone reductase II
Genes
SLY101256174
SPEN107018368
SOT102589607(TRII)
SSTN125856831
SDUL129871211
CANN107872392
LBB132615530 132615635 132615940
Reference
1
  Authors
Drager B, Hashimoto T, Yamada Y.
  Title
Purification and characterization of pseudotropine forming tropinone reductase from Hyoscyamus niger root cultures.
  Journal
Agric Biol Chem 52:2663-2667 (1988)
Reference
2
  Authors
Couladis MM Friesen JB, Landgrebe ME, Leete E.
  Title
Enzymes catalysing the reduction of tropinone to tropine and psi-tropine isolated from the roots of Datura innoxia.
  Journal
Pytochemistry 30:801-805 (1991)
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 90:9591-5 (1993)
DOI:10.1073/pnas.90.20.9591
  Sequence
Reference
4  [PMID:16426652]
  Authors
Drager B.
  Title
Tropinone reductases, enzymes at the branch point of tropane alkaloid metabolism.
  Journal
Phytochemistry 67:327-37 (2006)
DOI:10.1016/j.phytochem.2005.12.001
Other DBs
ExplorEnz - The Enzyme Database: 1.1.1.236
IUBMB Enzyme Nomenclature: 1.1.1.236
ExPASy - ENZYME nomenclature database: 1.1.1.236
BRENDA, the Enzyme Database: 1.1.1.236
CAS: 136111-61-0

KEGG   REACTION: R06734
Entry
R06734                      Reaction                               
Name
pseudotropine:NADP+ 3-oxidoreductase
Definition
Tropinone + NADPH + H+ <=> Pseudotropine + NADP+
Equation
Comment
pseudotropine forming tropinone reductase
Reaction class
RC00001  C00005_C00006
RC00144  C00783_C02066
Enzyme
Pathway
rn00960  Tropane, piperidine and pyridine alkaloid biosynthesis
rn01110  Biosynthesis of secondary metabolites
Brite
Enzymatic reactions [BR:br08201]
 1. Oxidoreductase reactions
  1.1  Acting on the CH-OH group of donors
   1.1.1  With NAD+ or NADP+ as acceptor
    1.1.1.236
     R06734  Tropinone + NADPH + H+ <=> Pseudotropine + NADP+
Orthology
K05354  tropinone reductase II [EC:1.1.1.236]
Other DBs
RHEA: 24247

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