IPP isomerase (IDI) catalyzes the isomerization of IPP to DMAPP and condensation of two IPP molecules to form GPP (geranyl diphosphate).
A hypothesis on the mechanism of inhibition in anticancer activity indicates that SQ reduces the activity of the HMG-CoA reductase enzyme by limiting the steps towards normal cholesterol synthesis and intermediate stages where geranyl diphosphate (GDP) and farnesyl diphosphate (FDP) produce important substrates for the biosynthesis of ubiquinones and for the prenylation (farnesylation) of proteins.
Plants produce many types of terpenoids that are all generated from the same precursors: IPP and its isomer DMAPP, which are catalyzed by their corresponding enzymes to synthesize geranyl diphosphate
(GPP), farnesyl diphosphate (FPP) and geranylgeranyldiphosphate (GGPP; Tholl, 2006).
The initial step in biosynthesis of isoprenoid side chain involves a condensation reaction between an IPP and its allelic isomer, Dimethylallyl diphosphate (DMADP) by Geranyl diphosphate
synthase (GPPS) which results in the formation of Geranyl diphosphate
(GPP) with ten carbons.
They settled on two classes of enzymes - three pinene synthases (PS) and three geranyl diphosphate
synthases (GPPS) - and experimented to see which combinations produced the best results.
FPP synthase (FPPS), a short-chain prenyltransferase, generates FPP by completing two sequential couplings: first IPP and dimethylallyl pyrophosphate (DMAPP) can condense in a head-to-tail manner to produce geranyl diphosphate
In more recent work, the purified elisabethatriene synthase was challenged with alternative shorter substrates, geranyl diphosphate
and famesyl diphosphate, resulting in the production of alternative diterpenes (32).
synthase that converts geranyl diphosphate
to linalool (Dudareva &