Polyisoprenyl diphosphates

Fig. 13 Synthesis of polyisoprenyl diphosphates, (a) Biosynthetic pathway in archaea. (b) Concept of the organic-aqueous dual-phase system. The light- and dark-shaded areas indicate the aqueous and organic phases, respectively. Double-headed and single-headed arrows indicate isomerization by IDI and consecutive condensation by IDS, respectively. Reprinted from [271], with permission from Elsevier...

The subsequent chain elongation step was confirmed to proceed via an addition of IPP to polyisoprenyl diphosphate to form isoprene units in cis configuration. Rubber polymerization is catalysed by rubber transferase (EC 2.5.1.20), a cw-prenyltransferase, and requires divalent cations such as Mg " or Mn as a cofactor. The proposed mechanism of rubber biosynthesis is shown in Figure 2.1. 

Investigation of the biosynthesis of a D-glucosyl polyisoprenyl diphosphate by Micrococcus lysodeikticus has been carried out using UDP-D-[ glucose. 

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