Biosynthesis of the sesquiterpene patchoulol from farnesyl pyrophosphate in leaf extracts of Pogostemon cablin (patchouli): mechanistic considerations

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(87)90425-5· OSTI ID:6132900

Croteau, R; Munck, S L; Akoh, C C; Fisk, H J; Satterwhite, D M

Several mechanistic alternatives have been proposed for the enzyme-catalyzed, electrophilic cyclization of farnesyl pyrophosphate to the tricyclic sesquiterpene alcohol patchoulol, which is the characteristic component of the essential oil of Pogostemon cablin (patchouli). These alternatives include schemes involving deprotonation-reprotonation steps and the intermediacy of the monocyclic and bicyclic olefins germacrene and bulnesene, respectively, and involving a 1,3-hydride shift with only tertiary cationic intermediates and without any deprotonation-reprotonation steps. Analytical studies, based on analyses of P. cablin leaf oil at different stages of plant development, and in vivo time-course investigations, using /sup 14/CO/sub 2/ and (/sup 14/C)sucrose, gave no indication that germacrene and bulnesene were intermediates in patchoulol biosynthesis. A soluble enzyme system from P. cablin leaves was prepared, which was capable of converting farnesyl pyrophosphate to patchoulol, and isotopic dilution experiments with both labeled and unlabeled olefins were carried out with this system to confirm that sesquiterpene olefins did not participate as fre intermediates in the transformation of the acyclic precursor to patchoulol. Patchoulol derived biosynthetically from (/sup 12/,/sup 13/-/sup 14/C;1-/sup 3/H)farnesyl pyrophosphate was chemically degraded to establish the overall construction pattern of the product. Similar studies with (/sup 12/,/sup 13/-/sup 14/C;6-/sup 3/H)farnesyl pyrophosphate as a precursor eliminated deprotonation steps to form bound olefinic intermediates in the biosynthesis of patchoulol, while providing supporting evidence for the hydride shift mechanism.

• Research Organization: Washington State Univ., Pullman
• OSTI ID: 6132900
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 256:1; ISSN ABBIA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
BARYONS
BIOSYNTHESIS
CARBOHYDRATES
CARBON 12
CARBON 13
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
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HADRONS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
METABOLISM
NUCLEI
NUCLEONS
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PLANTS
PROTONS
PYROPHOSPHATES
SACCHARIDES
SACCHAROSE
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES