Oxidoreductases;
Acting on the CH-CH group of donors;
With NAD+ or NADP+ as acceptor

(-)-menthone:NADP+ oxidoreductase

(1) (-)-menthone + NADP+ = (+)-pulegone + NADPH + H+ [RN:R06419];
(2) (+)-isomenthone + NADP+ = (+)-pulegone + NADPH + H+ [RN:R06420]

R06419 R06420

(-)-menthone [CPD:C00843];
NADP+ [CPD:C00006];
(+)-isomenthone [CPD:C11952]

NADH cannot replace NADPH as reductant. The Delta8,9-double bond of (+)-cis-isopulegone and the Delta1,2-double bond of (+/-)-piperitone are not substrates. The enzyme from peppermint (Mentha x piperita) converts (+)-pulegone into both (-)-menthone and (+)-isomenthone at a ratio of 70:30 for native enzyme but it does not catalyse the reverse reaction. This enzyme is a member of the medium-chain dehydrogenase/reductase superfamily.

EC 1.3.1.81 created 2008

1  [PMID:13679086]

Ringer KL, McConkey ME, Davis EM, Rushing GW, Croteau R.

Monoterpene double-bond reductases of the (-)-menthol biosynthetic pathway: isolation and characterization of cDNAs encoding (-)-isopiperitenone reductase and (+)-pulegone reductase of peppermint.

Arch Biochem Biophys 418:80-92 (2003)
DOI:10.1016/S0003-9861(03)00390-4

[ag:AAQ75423]