Ajmaline pathway side routes

The complexity of the ajmaline structure makes it difficult to identifying its biosynthetic pathway. The solution to this problem is an in-depth elucidation of each reaction step and each enzyme involved in the catalysis." This article reviews the relevant research on the ajmaline s main biosynthetic pathway and its side routes, the route beyond ajmahne, the application of in vivo NMR, the chemo-enzymatic significance of the involved enzymes and, their reaction mechanisms and the enzyme X-ray crystal stmctures. 

A number of side routes originate from various intermediates of the ajmaline pathway (AP) are shown in Figure 22. They lead to a complex biosynthetic network of sarpagan and ajmalan alkaloids in Rauvolfia. 

Figure 22 Side routes of the biosynthetic pathway of ajmaline ( indicates the enzymes (cDNAs) which have been heterologously expressed).

A side route may also take place at the end of the ajmahne pathway by meta-boUsm of ajmaline (1) itself By administering ajmaline (1) to the Rauuolfia suspended cells in high concentrations (up to 1 g/L), it is converted to a small novel group of six derivatives named raumaclines (Figures 34 and 39). These new alkaloids were, however, detected in the surrounding nutri-tion medium. This bioconversion can be summarized as Figure 34. 

The enzyme-catalyzed biosynthesis of the sarpagan-ajmalan-type firni-ihes of monoterpenoid indole alkaloids in the genus Rauvolfia, in particular R. serpentina Benth. ex Kurz, have recendy been delineated in detail. The major pathway leading to the structural intricate antiarrhythmic ajmaline, together with several side routes and bypasses, form a comprehensive and complex anabolic network of which a multitude of single-enzymatic... 

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