title: Deoxysarpagine hydroxylase--a novel enzyme closing a short side pathway of alkaloid biosynthesis in Rauvolfia.
abstract: Microsomal preparations from cell suspension cultures of the Indian plant Rauvolfia serpentina catalyze the hydroxylation of deoxysarpagine under formation of sarpagine. The newly discovered enzyme is dependent on NADPH and oxygen. It can be inhibited by typical cytochrome P450 inhibitors such as cytochrome c, ketoconazole, metyrapone, tetcyclacis and carbon monoxide. The CO-effect is reversible with light (450 nm). The data indicate that deoxysarpagine hydroxylase is a novel cytochrome P450-dependent monooxygenase. A pH optimum of 8.0 and a temperature optimum of 35 degrees C were determined. K(m) values were 25 microM for NADPH and 7.4 microM for deoxysarpagine. Deoxysarpagine hydroxylase activity was stable in presence of 20% sucrose at -25 degrees C for >3 months. The analysis of presence of the hydroxylase in nine cell cultures of seven different families indicates a very limited taxonomic distribution of this enzyme.
authors.affiliation: Johannes Gutenberg-University, Institute of Pharmacy, Department of Pharmaceutical Biology, Staudinger Weg 5, 55099 Mainz, Germany.
authors.forename: Bingwu
authors.initials: B
authors.lastname: Yu
authors.forename: Martin
authors.initials: M
authors.lastname: Ruppert
authors.forename: Joachim
authors.initials: J
authors.lastname: Stöckigt
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000528:radiation effects; D002248:Carbon Monoxide / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System; D006863:Hydrogen-Ion Concentration; D026121:Indole Alkaloids / Q000378:metabolism; D007700:Kinetics; D008027:Light; D009249:NADP; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000528:radiation effects; D011926:Rauwolfia / Q000201:enzymology*; D046948:Secologanin Tryptamine Alkaloids / Q000096:biosynthesis*; D013696:Temperature
chemical_list: D026121:Indole Alkaloids; D010940:Plant Proteins; D046948:Secologanin Tryptamine Alkaloids; D009249:NADP; D002248:Carbon Monoxide; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C475808:deoxysarpagine hydroxylase; C475809:sarpagine