In vivo and in vitro conversion of teasterone to typhasterol in cultured cells of Marchantia polymorpha [Bryophyta]
1999
Park, S.H. (Chung-Ang Univ., Seoul (Korea R.)) | Han, K.S. | Kim, T.W. | Shim, J.K. | Takatsuto, S. | Yokota, T. | Kim, S.K.
Identification by full-scan GC-MS revealed that [2H6]teasterone fed to suspension cultured tens of Marchantia polymorpha was converted to [2H6]3-dehydroteasterone and [2H6]typhasterol. This indicates that the cells carry out a C3-epimerization in which teasterone is converted to typhasterol via 3-dehydroteasterone. In vitro enzymatic conversions of teasterone to typhasterol were also investigated. A crude cytosolic solution prepared from Marchantia cells catalyzed not only the dehydrogenation of teasterone to 3-dehydroteasterone but also the reduction of 3-dehydroteasterone to typhasterol. The major 4-demethysterol in cultured M. polymorpha cells was 24-methylcholesterol, the precursor of brassinosteroids. These results suggest that enzymes similar to those involved in the early C-6 oxidation pathway of the brassinosteroid biosynthesis are present in the liverwort
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