Pathway: trans,trans-farnesyl diphosphate biosynthesis

General Background |FRAME: FARNESYL-PP| (farnesyl pyrophosphate, FPP) is a crucial compound involved in the biosynthesis of a variety of terpenoids including sesquiterpenoids and sterols. Moreover, FPP is also used in posttranslational modifications of proteins (farnesylation) which is believed to act as a membrane attachment device. The biosynthesis of FPP is largely thought to occur in the cytosol where sesquiterpenoids and sterols are produced. This cytosolic FPP is synthesized from the condensation of |FRAME: CPD-4211| (dimethylallyl pyrophosphate, DMAPP) and two molecules of |FRAME: DELTA3-ISOPENTENYL-PP| (isopentenyl pyrophosphate, IPP) originating from the |FRAME:PWY-922|. The synthesis of FPP is the result of two head-to-tail condensation reactions: first |FRAME: GERANYL-PP| (geranyl pyrophosphate, GPP) is formed from the condensation of DMAPP and IPP; then another IPP molecule is added to form FPP.