The enzymatic incorporation of isopentenyl pyrophosphate into polyisoprene in rubber particles from Parthenium argentatum Gray

A biochemical and ultrastructural analysis of rubber biosynthesis in Parthenium argentatum Gray in the Chihuahuan Desert

“…The latter makes up the majority of the living bark cells. RT found in the stem bark or in the washed rubber particles (WRP) catalyzes the transfer of allylic-PP initiators to isopentenyl-pyrophosphate (IPP) to initiate the polymerization reaction followed by the transfer of the rubber-PP to IPP to complete rubber polymer formation (Benedict, 1991;Benedict et al, 1990Benedict et al, , 1986Benedict et al, , 2012Cornish, 2001;Cornish and Backhaus, 1990). RT was assayed in the stem homogenates or WRP with Mg 2+ [ 14 C]-IPP, buffer and initiator dimethylallyl pyrophosphate (DMAPP), farnesyl diphosphate (FDP) or geranylgeranyl diphosphate (GGPP).…”

“…The molecular weight distribution (MWD) of the [ 14 C]-polyisoprene chains ranged from 10 3 to 10 6 Da with no preferential formation of high molecular weight [ 14 C]-polyisoprene in early incubation times that would indicate formation of the [ 14 C]-polyisoprene by the elongation of pre-existing rubber-PP present in the WRP (Fig. 2) (Benedict et al, 2012). The MWD of the [ 14 C]-polymer was evidence of the presence of a de novo synthesis by RT.…”

“…The gel permeation chromatographic separation of the [ 14 C]-polyisoprene chains biosynthesized in 1 h in reaction mixture without added DMAPP.Reprinted fromBenedict et al (2012).…”