Tropane alkaloids metabolic engineering

Oksman-Caldenty KM, Arroo R. Regulation of tropane alkaloid metabolism in plants and plant cell cultures. In Metabolic Engineering of Plant Secondary Metabolism. Verpoorte R, Alfermann AW, eds. 2000. Kluwer Academic Publishers, Dordrecht, the Netherlands, pp. 253-281. 

Nevertheless, genetic engineering of a key enzyme in a chosen pathway does not always result in the enhancement of the end product thus, overexpression of pmt gene carried out in A. belladonna resulted in a 5-fold increased in pmt transcript level but an unchanged tropane alkaloid profile (hyoscyamine and scopolamine), as well as the tropane alkaloids biosynthetic precursors tropine, pseudotropine and tropinone which were not affected [134-135], Similarly, the overexpression of tobacco pmt gene in Dubosia hybrid hairy root cultures produced amounts of tropane alkaloid similar to control roots [131, 136]. All these results seem to indicate the presence of different points of control in the tropane alkaloid metabolic pathway. 

Robins, R. J., Walton, N. J., Parr, A. J., Aird, E. H., Rhodes, J. C., and Hamill, J. D. (1994) Progress in the genetic engineering of the pyridine and tropane alkaloid biosynthetic pathways of Solanaceous plants. In Genetic Engineering of Plant Secondary Metabolism, pp. 1-33, Plenum Press, New York. 

The current status of knowledge of the biosynthesis of the tropane alkaloids is almost paradoxical our understanding of the mechanisms by which plants assemble the tropane nucleus (1) still leaves much to be desired whilst some of the late events in the formation of one particular tropane alkaloid, scopolamine (2), are understood in great detail. Applications of this knowledge in the sense of metabolic engineering of medicinal plants have even been described [5]. 

Metabolic Engineering for Tropane Alkaloids and Pyrrolidine Alkaloids... 

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