Entry
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
Product
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
Genes
LBB : 132615530 132615635 132615940
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 52:2663-2667 (1988)
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 30:801-805 (1991)
Reference
Authors
Nakajima K, Hashimoto T, Yamada Y
Title
Two tropinone reductases with different stereospecificities are short-chain dehydrogenases evolved from a common ancestor.
Journal
Sequence
Reference
Authors
Drager B.
Title
Tropinone reductases, enzymes at the branch point of tropane alkaloid metabolism.
Journal
Other DBs
ExPASy - ENZYME nomenclature database: 1.1.1.236