title: Purification and properties of (S)-tetrahydroprotoberberine oxidase from suspension-cultured cells of Berberis wilsoniae.
abstract: A novel oxidase, catalyzing in the presence of oxygen the removal of four hydrogen atoms from a number of tetrahydroprotoberberines with simultaneous production of 1 mol H2O2 and H2O each, has been discovered and purified to homogeneity from Berberis wilsoniae cell cultures. This enzyme, (S)-tetrahydroprotoberberine oxidase, exhibited strict specificity for the (S)-enantiomer of tetrahydroprotoberberines and 1-benzylisoquinoline alkaloids, a pH optimum at 8.9, a molecular mass of 105 kDa and consisted of two subunits each of 53 kDa and covalently bound flavin. The Km values for (S)-scoulerine and (S)-norreticuline were 25 microM and 150 microM respectively. Concentration of the end-products, either protoberberines or H2O2, greater than 0.5 mM caused severe enzyme inhibition. This catalyst was responsible for the conversion of (S)-tetrahydrocolumbamine to the key intermediate, columbamine, in the metabolic pathway leading to berberine, jatrorrhizine and palmatine.
authors.affiliation: Lehrstuhl für Pharmazeutische Biologie, Universität München, Federal Republic of Germany.
authors.forename: M
authors.initials: M
authors.lastname: Amann
authors.forename: N
authors.initials: N
authors.lastname: Nagakura
authors.forename: M H
authors.initials: MH
authors.lastname: Zenk
mesh_terms: D001600:Berberine Alkaloids / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D010088:Oxidoreductases / Q000302:isolation & purification*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010946:Plants, Medicinal / Q000201:enzymology*; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
chemical_list: D001600:Berberine Alkaloids; C010941:discretamine; C055786:columbamine; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C056768:tetrahydroprotoberberine oxidase