Enzymatic Formation of Raucaffricine, the Major Indole Alkaloid of <i>Rauwolfia serpentina</i> Cell‐Suspension Cultures

Abstract

Abstract The major alkaloid from Rauwolfia serpentina cell‐suspension cultures, the glucoalkaloid raucaffricine ( 2 ), was enzymatically formed from vomilenine ( 1 ) and UDPG in presence of microsomal‐bound enzyme. This glucosyltransferase exhibits a relatively high substrate specificity with strong preference for 1 and UDPG. The apparent K m values for 1 and UDPG were 40 μ M and 0.8 m M , respectively, for raucaffricine formation. Optimum transferase activity was observed at 50° and pH 6.3. The taxonomic distribution of this enzyme seems to be very limited because transferase can he exclusively detected in raucaffricine‐producing plant cells.