Geranylgeranyl pyrophosphate GGPP

In similar fashions, the core pathway up to C25 compounds (five isoprene units) is formed by sequential addition of C5 moieties derived from IPP to a starter unit derived from DMAPP. Thus, sesquiterpenes are formed form the precursor 2E, hS-farnesyl pyrophosphate (FPP), and diterpenes from 2E, 6E, IO -geranylgeranyl pyrophosphate (GGPP). The parents of triterpenes and tetraterpenes are formed by reductive coupling of two FPPs or GGPPs, respectively. Rubbers and other polyisoprenoids are produced from repeated additions of C5 units to the starter unit GGPP. 

The prenyl transferase from avian liver has been crystallized,40 and was found to be a dimer of molecular weight 86 000 dalton the subunits could not be resolved by SDS electrophoresis. The enzyme catalysed the formation of FPP from IPP and either DMAPP or GPP, and this was accompanied by the synthesis of small amounts of geranylgeranyl pyrophosphate (GGPP). This is the first stable crystalline enzyme of the steroid and terpenoid pathways to be prepared. 

Subsequent addition of a second or third molecule of IPP leads to the formation of Ci5 farnesyl pyrophosphate (FPP) and the C20 geranylgeranyl pyrophosphate (GGPP). The chain elongation is a head-to-tail condensation process, which forms carbon-carbon bonds between C-4 of IPP and C-1 of the aDyhc... 

It is now known that there are more than 380 kinds of natural taxane in Taxus. The biosynthesis of taxanes is generally believed to occur as follows. Farnesyl diphosphate (FPP) and isopentenyl pyrophosphate (IPP) are first catalyzed by GGPP synthase to produce geranylgeranyl-pyrophosphate (GGPP), and then taxa-4(5),ll(12)-diene is produced under the action of taxa-diene synthase. Next, taxanes are produced by the hydroxylase oxidation of the taxa-4(20),ll(12)-dien-5a-ol diterpene parent ring. The biosynthetic pathway for taxanes is illustrated in Figure 6.7. 

Figure 10.3 Geranylgeranyl pyrophosphate (GGPP) suppresses statin-induced muscle toxicity. C2C12 myotubes were treated for 48 h with simvastatin in the absence or...

The progenitor of C20 isoprenoids is geranylgeranyl pyrophosphate (GGPP) (1) (Fig. 22.2). The mechanism of condensation probably is the same as that for sesquiterpenes... 

Isoprene building block Geranylgeranyl pyrophosphate (GGPP)... 

Carotenoids in kiwifruits changed to lycopene (3) by their biosynthetic enzymes from geranylgeranyl pyrophosphate (GGPP, 11), then lycopene (3) was divided to two biosynthetic pathways to lutein (6) and neoxanthin (7), respectively (Figure 2a) (Figure 2b) [4, 5,6],... 

The initiation of the carotenoid biosynthesis pathway requires four IPP units that will be joined progressively including isomerization and condensation reactions to form geranylgeranyl pyrophosphate (GGPP), which is the immediate precursor of carotenoids (Scheme 92.1). Two units of GGPP would then be condensed to form 15-di-phytoene. This reaction is catalyzed by the enzyme phytoene synthase (PSY). 

GPP. See Geranyl pyrophosphate (GPP) GGPP. See Geranylgeranyl diphosphate (GGPP) Geranylgeranyl pyrophosphate (GGPP)... 

IPP and DMAPP react as shown in Scheme 102.4 to generate geranyl pyrophosphate (GPP), whose further reaction with IPP produce famesyl pyrophosphate (FPP) that reacts with another molecule of IPP to afford geranylgeranyl pyrophosphate (GGPP), representing the linear diterpene C20 precursor. 

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