The Taxus Metabolome and the Elucidation of the Taxol® Biosynthetic Pathway in Cell Suspension Cultures

4 Conclusion

The metabolome of an organism strictly refers to all metabolites produced during its life. The Taxus metabolome, as briefly described in this chapter, relates to that part of Taxus secondary metabolism that begins with the formation of taxa-4,11-diene and ends with the production of a taxane diterpenoid, such as the pharmaceutically important drug taxol. The metabolic pathways that originate fromtaxa-4,11-diene and result in the formation of the over 400 taxoids so far described form a complex network through which taxol biosynthesis is woven. While less than 40 of these taxoids (comprising about 85 mass %) have been characterized in our plant cell cultures, most are not involved in taxol biosynthesis. Identification of the taxoids that are produced in our Taxus plant cell culture system and understanding their relationship to other intermediates in the taxol biosynthetic pathway provide clues to the order of the synthesis of intermediates and branch points in this complex metabolic grid. This knowledge is critical for the intelligent targeting of genes for future metabolic engineering of plant cell cultures for increased taxol production.

Taxol® is a registered trademark of the Bristol-Meyers-Squibb company. The approved generic term for the drug is paclitaxel. Due to historic precedent and the abundance of taxoids with names derived from “taxol,” we will use the more familiar term “taxol” when referring to this compound.