title: Biosynthesis of steroidal alkaloids in Solanaceae plants: incorporation of 3β-hydroxycholest-5-en-26-al into tomatine with tomato seedlings.
abstract: The C-26 amino group of tomatine, a representative Solanaceae steroidal alkaloid, is introduced in an early step of its biosynthesis from cholesterol. We recently proposed a transamination mechanism for the C-26 amination as opposed to the previously proposed mechanism involving a nitrogen nucleophilic displacement. In the present study, a deuterium labeled C-26 aldehyde, (24,24,27,27,27-(2)H5)-3β-hydroxycholest-5-en-26-al, was synthesized and fed to a tomato (Solanum lycopersicum) seedling. LC-MS analysis of the biosynthesized tomatine indicated that the labeled aldehyde was incorporated into tomatine. The finding strongly supports the intermediacy of the aldehyde and the transamination mechanism during C-26 amination.
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama 2-12-1, Meguro-ku, Tokyo 152-8551, Japan; RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ohyama
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama 2-12-1, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Okawa
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama 2-12-1, Meguro-ku, Tokyo 152-8551, Japan. Electronic address: fujimoto.y.aa@m.titech.ac.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujimoto
mesh_terms: D000470:Alkaloids / Q000096:biosynthesis* / Q000737:chemistry; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D008968:Molecular Conformation; D036226:Seedlings / Q000737:chemistry / Q000378:metabolism*; D019657:Solanaceae / Q000737:chemistry / Q000378:metabolism*; D013256:Steroids / Q000096:biosynthesis* / Q000737:chemistry; D014053:Tomatine / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000470:Alkaloids; D013256:Steroids; D014053:Tomatine; D002784:Cholesterol
keywords: Biosynthesis; Solanum lycopersicum; Steroidal alkaloid; Tomatine; Transamination