Biosynthesis of Chloroplastidic and Extrachloroplastidic Terpenoids in Liverwort Cultured Cells:  <SUP>13</SUP>C Serine as a Probe of Terpene Biosynthesis via Mevalonate and Non-mevalonate Pathways

Two terpenoid biosynthetic pathways, the mevalonate and non-mevalonate (glyceraldehyde phosphate-pyruvate) routes, were examined by feeding ¹³C-labeled serines ([1-¹³C]- and [3-¹³C]-) to the cultured cells of the liverwort, Heteroscyphus planus. The labeling patterns observed in the isoprenoid unit of the biosynthetically ¹³C-labeled stigmasterol corresponded to those expected from the mevalonate pathway, while those of the phytyl side chain corresponded to those from the non-mevalonate pathway. Thus, serine is a potential probe to determine the origin of terpenoid biosynthesis, in either the mevalonate or non-mevalonate pathway.