muthuvenkat
commented
12 years ago Hi Kristian,
The structures given in CHEBI:4372 and CHEBI:49177are correct for (6S)- and (6R)-dehydrovomifoliol, respectively. It is not clear whether KEGG C02533 has correct name but the wrong structure, or the correct structure but the wrong name.
On the IUBMB site for EC 1.1.1.221, http://www.chem.qmul.ac.uk/iubmb/enzyme/EC1/1/1/221.html the reaction is described as: (6S,9R)-6-hydroxy-3-oxo-α-ionol + NAD+ = (6R)-6-hydroxy-3-oxo-α-ionone and the same description is given for the reaction diagram: http://www.chem.qmul.ac.uk/iubmb/enzyme/reaction/terp/111221.html However, the structures shown the product is (6S), not (6R). Further, the glossary gives: dehydrovomifoliol = (6R)-6-hydroxy-3-oxo-α-ionone = (4S)-4-hydroxy-3,5,5-trimethyl-4-[(1E)-3-oxobut-1-enyl]cyclohex-2-en-1-one But this cannot be right - either the stereocentre is (R), or it is (S) - it cannot be both. Curiously, the only reference given (Phytochem., 1984, v23, p2769-2771) does not mention (R) or (S). It says the product is (+/-), but only because it gave an identical spot on a tlc plate to racemic material - which would have been the case irrespective of whether the product was (R), (S), or racemic! MetaCyc depict both the reactant and the product as racemic: http://metacyc.org/META/NEW-IMAGE?type=NIL&object=VOMIFOLIOL-4-DEHYDROGENASE-RXN&redirect=T
In short, the structures in ChEBI correspond to the ChEBI names. But I have no idea which one should be used for depicting EC 1.1.1.221 - the IUBMB site left me confused!
Cheers, Gareth
Original comment by: G-Owen
Hi,
(6S)-dehydrovomifoliol, is it really the 6S isomer that is drawn? Likewise for chebi:49177 (6R)-dehydrovomifoliol
chebi:4372 is x-linked to KEGG C02533 with the name (6R)-dehydrovomifoliol
/Kristian
Reported by: axelsen