Acetyl Coenzyme A: Deacetylvindoline O-Acetyltransferase, A Novel Enzyme from Catharanthus

Isolation and Characterization of a 2-Oxoglutarate Dependent Dioxygenase Involved in the Second-to-Last Step in Vindoline Biosynthesis

“…All alkaloids were from our laboratory collection and were isolated or synthesized as previously described (6,9). All column chromatography supports and the fast protein liquid chromatography system were from Pharmacia Fine Chemicals.…”

“…The commercial importance of these compounds has prompted many attempts to produce them using plant tissue culture methodology (3,11,20). The discovery of catharanthine producing cell lines has demonstrated the biosynthetic potential of C. roseus cell cultures (19,25,27), but analogous results have not been obtained for the production of vindoline or the dimeric indole alkaloid derivatives (3, 11, ' Several enzymes involved in the conversion of tabersonine to vindoline have been identified and characterized (6,9,12,14,15). These enzymes include an O-methyltransferase (15), a thylakoid membrane associated N-methyltransferase (9), and an O-acetyltransferase (6,14) all of which are involved in vindoline biosynthesis.…”

“…The discovery of catharanthine producing cell lines has demonstrated the biosynthetic potential of C. roseus cell cultures (19,25,27), but analogous results have not been obtained for the production of vindoline or the dimeric indole alkaloid derivatives (3, 11, ' Several enzymes involved in the conversion of tabersonine to vindoline have been identified and characterized (6,9,12,14,15). These enzymes include an O-methyltransferase (15), a thylakoid membrane associated N-methyltransferase (9), and an O-acetyltransferase (6,14) all of which are involved in vindoline biosynthesis. Each enzyme has been shown to possess high selectivity and affinity for their respective substrates, suggesting their unique roles in this biosynthetic pathway (6,9,12,14,15).…”

“…These enzymes include an O-methyltransferase (15), a thylakoid membrane associated N-methyltransferase (9), and an O-acetyltransferase (6,14) all of which are involved in vindoline biosynthesis. Each enzyme has been shown to possess high selectivity and affinity for their respective substrates, suggesting their unique roles in this biosynthetic pathway (6,9,12,14,15).…”

The formation of 3α‐ and 3β‐acetoxytropanes byDatura stramonium transformed root cultures involves two acetyl‐CoA‐dependent acyltransferases

“…This may indicate that the substrate is uncharged tropine or pseudotropine, the deprotonation of the nitrogen being strongly favoured at pH's above 8.5. Some other acetyl-CoA-utilising enzymes involved in alkaloid biosynthesis, such as vinorine synthase from Rauwolfia serpentina [l 2] and acetylCoA:deacetylvindoline O-acetyl transferase from Catharanthus roseus [13]. have also been found to have pH optima in this range.…”