(All-E) prenyl diphosphate synthases catalyze the con-secutive condensation of isopentenyl diphosphates with allylic prenyl diphosphates, producing products with vari-ous chain-lengths that are unique for each enzyme. Some short-chain (all-E) prenyl diphosphate synthases, . farnesyl diphosphate synthases and geranylgeranyl diphosphate synthases contain characteristic amino acid sequences around the allylic substrate binding sites, which have been shown to play a role in determining the chain-length of the product
