Biosynthesis of abietane diterpenoids in cultured cells of Torreya nucifera var. radicans: biosynthetic inequality of the FPP part and the terminal IPP

Labelling experiments with [1-13C] glucose, [1-13C] sodium acetate and [1,2-13C2] sodium acetate proved that the fundamental isopentenyl diphosphate (IPP) unit, constituting GGPP in the abietane diterpenoids, were biosynthesized via the GAP/pyruvate pathway, as well as the acetate/mevalonate pathway in the cultured cells of Torreya nucifera var. radicans. In addition, the terminal IPP showed the preferential labelling from the GAP/pyruvate pathway and unfavorable labelling from the acetate/mevalonate pathway, suggesting that the biosynthetic route leading to the terminal IPP involved the GAP/pyruvate pathway more and the acetate/mevalonate pathway less, compared with the FPP part. Furthermore, it was also found that the utilization of the two pathways in the formation of the FPP part and the terminal IPP was dependent on the exogenous precursors through the simultaneous administration of [1-13C] sodium acetate and unlabelled glucose.