TRITERPENOID BIOSYNTHESIS IN THE SEEDLING OF EUPHORBIA-LATHYRIS L FROM SUCROSE AND AMINO-ACIDS

The triterpenoid biosynthesis from sucrose and several amino acids was investigated with 9-day-old Euphorbia lathyris seedlings. Tracer experiments with [U-C-14]sucrose demonstrated that sucrose was mainly incorporated into latex triterpenols. Several [U-C-14]amino acids were found to be efficient precursors in the synthesis of sterols and the wax triterpene ketones. The incorporation data of sucrose and amino acids into triterpenoids together with the daily uptake of these substrates from the endosperm were used to estimate the daily triterpenoid production from each substrate species. Sucrose was quantitatively the most important precursor in triterpenoid biosynthesis. About 10% of the sterols and wax triterpenoids were produced from the amino acids.