Regioselectivity and Deuterium Isotope Effects in Geraniol Hydroxylation by the Cytochrome P-450 Monooxygenase from Catharanthus roseus (L.) G. DON
✍ Scribed by Heinz Fretz; Wolf-Dietrich Woggon
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- German
- Weight
- 794 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
The hydroxylation of geraniol( ) by cytochrome P-450 (P-450c0,h) from the subtropical plant Catharanthus roseus (L.) G. DON was optimised to give 8-hydroxygeraniol(9) as the single product in 35% yield. Incubations of different I3C-and 2H-labelled geraniols revealed that H-abstraction is completely regioselective in favour of the CH, group trans to the chain at C(6) of 8. An intramolecular isotope effect kH/kD = 8.0 was determined, suggesting that H-abstraction is one of the major rate-contributing steps; however, the intermolecular isotope effect was surprisingly inverse at low conversion kH/kD = 0.50, indicating the existence of rate-contributing steps preceding the first irreversible, isotope-sensitive reaction in the sequence.