<jats:title>Abstract</jats:title><jats:p>The major alkaloid from <jats:italic>Rauwolfia serpentina</jats:italic> cell‐suspension cultures, the glucoalkaloid raucaffricine (<jats:bold>2</jats:bold>), was enzymatically formed from vomilenine (<jats:bold>1</jats:bold>) and UDPG in presence of microsomal‐bound enzyme. This glucosyltransferase exhibits a relatively high substrate specificity with strong preference for <jats:bold>1</jats:bold> and UDPG. The apparent K<jats:sub>m</jats:sub> values for <jats:bold>1</jats:bold> and UDPG were 40 μ<jats:sc>M</jats:sc> and 0.8 m<jats:sc>M</jats:sc>, 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.