Isoprenoids taxol

Besides their essential roles in nature, isoprenoids are of commercial importance in industry. Some isoprenoids have been used as flavors, fragrances, spices, and food additives, while many are used as pharmaceuticals to treat an array of human diseases, such as cancer (Taxol), malaria (artemisinin), and HIV (coumarins). In contrast to the huge market demand, isoprenoids are present only in low abundance in their host organisms. Thus, isolation of the required isoprenoids consumes a large quantity of natural resources. Furthermore, owing to their structural complexity, total chemical synthesis is often not commercially feasible. For these reasons, metabolic engineering may provide an alternative to produce these valuable isoprenoids [88,89]. 

The IPP monomer serves as the universal building block for the production of all isoprenoids, including artemisinine, carotenoids, and Taxol. Thus, an engineered strain with high potential for generating IPP provides a platform for production of a variety of complex isoprenoids. The presence of two IPP synthesis pathways allows two approaches for engineering such strains. One is to introduce a heterozygous pathway and the other is to alter or modify the native pathway. Both approaches have been accomplished in E. coli. 

Besumbes O, Sauret-Giieto S, Phillips MA, Imperial S, Rodn guez-Concepcion M, Boronat A. (2004) Metabolic engineering of isoprenoid biosynthesis in Arabidopsis for the production of taxadiene, the first committed precursor of taxol. Biotechnol Bioeng 88 168-175. 

Ajikumar PK, Xiao WH, Tyo KE, Wang Y, Simeon F, Leonard E, Mucha O, Phon TH, Pfeifer B, Stepha-nopoulos G (2010) Isoprenoid pathway optimization for Taxol precursor overproduction in Escherichia coli. Science 330 70-74... 

The various PLC techniques were compared and trends in PLC summarized by Nyiredy (1996). The following recent applications for compound isolations by classic, capillary-flow PLC have been published photodegradation products of primaquine formed in an aqueous medium (Kristensen et al., 1993) synthesized isoprenoid diphosphates (20 mg of pure compound recovered from a single plate) (Kennedy Keller and Thompson, 1993) brain lipids (Deleva et al., 1992) components from aloe sap (0.75 mm layers of silanized silica gel and 0.5 mm of silica gel were developed in horizontal sandwich chambers) (Wawrzynowicz et al., 1994) taxol and cephalomannine from Taxus cuspidata (silica gel preparative plates developed with heptane-dichloromethane-ethyl acetate, 11 8 1) (Glow-niak et al., 1996) fenvalerate in a pesticide formulation (1-mm silica gel layers developed with hexane-acetone, 9 1, marker spots detected with o-dinitroben-zene-p-nitrobenzaldehyde reagent) (Gupta et al., 1996) and L-omithine-L-... 

Ajikumar PK et al (2010) Isoprenoid pathway optimization for Taxol precursor overproduction in Escherichia coli. Science 330 70-74... 

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