Biosynthesis of monoterpenes. Stereochemistry of the enzymatic cyclizations of geranyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene

Journal Article · Sun Feb 05 04:00:00 EST 1989 · J. Biol. Chem.; (United States)

OSTI ID:6272226

Croteau, R; Satterwhite, D M; Wheeler, C J; Felton, N M

The conversion of geranyl pyrophosphate to (+)-alpha-pinene and to (-)-beta-pinene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)- and to (+)-(3S)-linalyl pyrophosphate, respectively, and the subsequent cyclization of the anti, endo-conformer of these bound intermediates by mirror-image sequences which should result in the net retention of configuration at C1 of the geranyl precursor. Incubation of (1R)-(2-14C,1-3H)- and (1S)-(2-14C,1-3H)geranyl pyrophosphate with (+)-pinene cyclase and with (-)-pinene cyclase from common sage (Salvia officinalis) gave labeled (+)-alpha- and (-)-beta-pinene of unchanged 3H/14C ratio in all cases, and the (+)- and (-)-olefins were stereoselectively converted to (+)- and (-)-borneol, respectively, which were oxidized to the corresponding (+)- and (-)-isomers of camphor, again without change in isotope ratio. The location of the tritium was determined in each case by stereoselective, base-catalyzed exchange of the exo-alpha-hydrogens of these derived ketones. The results indicated that the configuration at C1 of the substrate was retained in the enzymatic transformations to the (+)- and (-)-pinenes, which is entirely consistent with the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate, transoid to cisoid rotation, and anti, endo-cyclization of the latter. The absolute stereochemical elements of the antipodal reaction sequences were confirmed by the selective enzymatic conversions of (3R)- and (3S)-1Z-(1-3H)linalyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene, respectively, and by the location of the tritium in the derived camphors as before. The summation of the results fully defines the overall stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to the antipodal pinenes.

• Research Organization: Washington State Univ., Pullman (USA)
• OSTI ID: 6272226
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 264:4; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CYCLASES
ENZYMES
ISOTOPE APPLICATIONS
ISOTOPE RATIO
LABELLED COMPOUNDS
LYASES
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PYROPHOSPHATES
STEREOCHEMISTRY
SYNTHESIS
TERPENES
TRACER TECHNIQUES
TRITIUM COMPOUNDS