ENZYMATIC FORMATION OF RAUCAFFRICINE, THE MAJOR INDOLE ALKALOID OF RAUWOLFIA-SERPENTINA CELL-SUSPENSION CULTURES

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-mu-M and 0.8 mM, respectively, for raucaffricine formation. Optimum transferase activity was observed at 50-degrees and pH 6.3. The taxonomic distribution of this enzyme seems to be very limited because the transferase can be exclusively detected in raucaffricine-producing plant cells.