SEPARATION AND CHARACTERIZATION OF CYTOKININ-INDUCIBLE (S)-TETRAHYDROBERBERINE OXIDASES CONTROLLING BERBERINE BIOSYNTHESIS IN THALICTRUM-MINUS CELL-CULTURES

Three forms of cytokinin-induced tetrahydroberberine (THE) oxidase from Thalictrum minus cell suspension cultures were individually separated by chromatography using DEAE-TOYOPEARL. Two of them were (S)-THB-specific oxidases, whereas the third was found to be a non-stereospecific one. The stereospecific oxidases were different from each other not only in the K-m value, but also in the time course of activation induced by 6-benzylaminopurine (BAP). The substrate specificity of these oxidases from T. minus cells was more similar to that reported for the (S)-THB oxidase of Coptis japonica than that for Berberis stolonifera cell cultures.