A newly-detected reductase from Rauvolfia closes a gap in the biosynthesis of the antiarrhythmic alkaloid ajmaline.
A new enzyme, 1,2-dihydrovomilenine reductase (E.C. 1.3.1), has been detected in Rauvolfia cell suspension cultures. The enzyme specifically converts 2beta( R)-1,2-dihydrovomilenine through an NADPH-dependent reaction into 17-O-acetylnorajmaline, a close biosynthetic precursor of the antiarrhythmic alkaloid ajmaline from Rauvolfia. A five-step purification procedure using SOURCE 30Q chromatography, hydroxyapatite chromatography, 2',5'-ADP Sepharose 4B affinity chromatography and ion exchange chromatography on DEAE Sepharose and Mono Q delivered an approximately 200-fold enriched enzyme in a yield of approximately 6%. SDS-PAGE showed an M r for the enzyme of approximately 48 kDa. Optimum pH and optimum temperature of the reductase were at pH 6.0 and 37 degrees C. The enzyme shows a limited distribution in cell cultures expressing ajmaline biosynthesis, and is obviously highly specific for the ajmaline pathway.
Gao
Shujuan
S
Johannes Gutenberg-University Mainz, Institute of Pharmacy, Department of Pharmaceutical Biology, Germany.
von Schumann
Gerald
G
Stöckigt
Joachim
J
D000404:Ajmaline / Q000096:biosynthesis*; D000889:Anti-Arrhythmia Agents / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D010088:Oxidoreductases / Q000737:chemistry*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D008517:Phytotherapy; D011926:Rauwolfia
D000889:Anti-Arrhythmia Agents; D000404:Ajmaline; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C469086:1,2-dihydrovomilenine reductase