Information AboutTerpenoid |
| CATEGORIES ABOUT TERPENOID | |
| terpenes and terpenoids | |
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Plant terpenoids are extensively used for their aromatic qualities. They play a role in traditional herbal remedies and are under investigation for antibacterial, antineoplastic and other pharmaceutical effects. Terpenoids contribute to the scent of Eucalyptus , the flavors of Cinnamon , Cloves and Ginger and the color of yellow flowers. Well-known terpenoids include Citral , Menthol , Camphor and the Cannabinoid s found in the Cannabis plant. The Steroid s and Sterol s in animals are biologically produced from terpenoid precursors. Sometimes terpenoids are added to Protein s, e.g. to enhance their attachment to the Cell Membrane ; this is known as Isoprenylation . STRUCTURE AND CLASSIFICATION Terpene s are Hydrocarbon s resulting from the combination of several Isoprene units. Terpenoids can be thought of as modified terpenes, where Methyl Group s have been moved or removed, or Oxygen atoms added. (Some authors use the term "terpene" more broadly, to include the terpenoids.) Just like terpenes, the terpenoids can be classified according to the number of isoprene units used:
Terpenoids can also be classified according to the number of cyclic structures they contain. BIOSYNTHESIS There are two Metabolic Pathway s of creating terpenoids: Mevalonic acid pathway Many organisms manufacture terpenoids through the HMG-CoA Reductase Pathway , the pathway that also produces Cholesterol . The reactions take place in the Cytosol . The pathway was discovered in the 1950s . MEP/DOXP pathway The MEP/DOXP pathway, also known as 2-C-methyl-D-erythritol 4-phosphate/deoxy-xylulose phosphate pathway or Mevalonic Acid independent pathway takes place in the Plastid s of plants. It was discovered in the late 1980s. Pyruvate is converted by DOXP synthase (DXS) to 1-Deoxy-D-xylulose-5-P and by DOXP reductase (DXR) to 2-C-Methyl-D-erythritol-4-P (MEP) and in multiple steps to Isopentenyl Pyrophosphate (IPP) and Dimethylallyl Pyrophosphate (DMAPP). DMAPP is a common metabolite in both pathways and an exchange of DMAPP would be possible. Out of this intermediate, Isoprene , monoterpenoids (10-carbon) diterpenoids (20-carbon), Carotenoid s (40-carbon), Chlorophyll s and Plastoquinone -9 (45-carbon) are formed. Intermediates are Geranyl Pyrophosphate (GPP) and Geranylgeranyl Pyrophosphate (GGPP). Both intermediates can also be found in the MVA pathway. Although both pathways, MVA and MEP, operate independently under normal conditions, interactions between them have been reported repeatedly.
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