geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Biosynthesis of monoterpenes stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to camphane and isocamphane monoterpenes


, : Biosynthesis of monoterpenes stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to camphane and isocamphane monoterpenes. Archives of Biochemistry & Biophysics 277(2): 374-381

The conversion of geranyl pyrophosphate to (+)-bornyl pyrophosphate and (+)-camphene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)-linalyl pyrophosphate and the subsequent cyclization of this bound intermediate. In the case of (-)-bornyl pyrophosphate and (-)-camphene, isomerization of the substrate to the (+)-(3S)-linalyl intermediate precedes cyclization. The geranyl and linalyl precursors were shown to be mutually competitive substrates (inhibitors) of the relevant cyclization enzymes isolated from Salvia officinalis (sage) and Tanacetum vulgare (tansyl) by the mixed substrate analysis method, demonstrating that isomerization and cyclization take place at the same active site. Incubation of partially purified enzyme preparations with (3R)-[1Z-3H]linalyl pyrophosphate plus [1-14C]geranyl pyrophosphate gave rise to double-labeled (+)-bornyl pyrophosphate and (+)-camphene, whereas incubation of enzyme preparations catalyzing the antipodal cyclizations with (3S)-[1Z-3H]-linalyl pyrophosphate plus [1-14C]geranyl pyrophosphate yielded double-labeled (-)-bornyl pyrophosphate and (-)-camphene. Each product was then transformed to the corresponding (+)- or (-)-camaphor without change in the 3H:14C isotope ratio, and the location of the tritium label was deduced in each case by stereoselective, base-catalyzed exchange of the exo-.alpha.-hydrogen of the derived ketone. The finding that the 1Z-3H of the linalyl precursor was positioned at the endo-.alpha.-hdyrogen of the corresponding camphor in all cases, coupled to the previously demonstrated retention of configuration at C1 of the geranyl substrate in these transformations, confirmed the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate and the cyclization of the latter via the anti, endo-conformer. These relative stereochemical elements, in combinations with the observed enantiospecificities of the enzymes for the linalyl intermediates, allows definition of the overall absolute stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to the antipodal camphane (bornane) and isocamphane monoterpenoids.

US$19.90

PMID: 2178556

DOI: 10.1016/0003-9861(90)90593-n


Other references

Jones, P.S.; Winslow, B.W.; Lee, J.W.; Burns, M.; Zhang, X.Esther., 2011: Development of a caregiver empowerment model to promote positive outcomes. Family members caring for aging parents experience both negative and positive outcomes from providing care. Theoretical explanations for negative outcomes have been developed. There is need for models that explain and predict positive outcomes. Th...

Bellows J.G.; Bellows R.T., 1975: Cataract due to trauma cataracta complicata and displacement of the lens part a traumatic cataract. BELLOWS, JOHN G (ED ) CATARACT AND ABNORMALITIES OF THE LENS XIII+533P ILLUS GRUNE and STRATTON, INC : NEW YORK, N Y , U S A ; LONDON, ENGLAND ISBN 0-8089-0842-1 265-272

al-Quran, F.A.; Lyons, M.F., 1999: The immediate effect of hard and soft splints on the EMG activity of the masseter and temporalis muscles. The aim of this study was to compare the effects of hard and soft splints on the activity of the anterior temporalis and masseter muscles. Surface EMG recordings were made from these muscles during clenching at 10% of maximum, 50% of maximum and a...

Yamane, I.; Sato, K., 1966: Determination of organic acids in flooded soils. 1. A modified Wiseman-Irvin method. In this modification of the method (originally used for silage analysis), butyric, propionic, acetic, formic and lactic acids can be determined more easily and rapidly. Celite 503 treated with HC1 is recommended as the adsorbent carrier.

Repke, D.B.; Ferguson, W.J., 1982: Psilocin analogs 3. synthesis of 5 methoxy 1 2 3 4 tetra hydro 9h pyrido 3 4 beta indoles and 5 hydroxy 1 2 3 4 tetra hydro 9h pyrido 3 4 beta indoles. A number of tetrahydro-.beta.-carbolines were prepared with oxygen substituents at C-5. This class of compounds represents a hybrid between 2 naturally occuring groups of hallucinogenic molecules, the 4-hydroxytryptamines and the 6- and 7-oxygenat...

Schmechta H., 1972: Comparative investigation on the blood type determination by means of the diffusion method and the immuno electro osmophoresis. Zeitschrift fuer Aerztliche Fortbildung 66(19): 1001-1003

Gupta, C.U.; Veinot, R.L., 1974: Response of crops to sulfur under greenhouse conditions. Rutabaga showed the largest and wheat the least response to added S. Cauliflower, alfalfa and barley showed intermediate response. The S-deficient plants were stunted and slow to mature and had light-yellow leaf colorations. Available soil SO4-S l...

Brink, H.I., 1986: Nursing and research: an introduction to methods of data collection. Nursing Rsa 1(5): 18-19

Okamoto-Barth, S.; Tanaka, M.; Kawai, N.; Tomonaga, M., 2007: Looking compensates for the distance between mother and infant chimpanzee. The development of visual interaction between mother and infant has received much attention in developmental psychology, not only in humans, but also in non-human primates. Recently, comparative developmental approaches have investigated whether t...

Kurihara, J.; Hu, B.R.n; Wieloch, T., 1994: Changes in the tyrosine phosphorylation of mitogen-activated protein kinase in the rat hippocampus during and following severe hypoglycemia. The changes in the levels of tyrosine-phosphorylated proteins in the cytosolic fraction of the rat hippocampus subjected to severe hypoglycemia were analyzed. A marked increase in tyrosine phosphorylation of a 43-kDa protein was observed at 30 min...