The enzymatic synthesis of rubber polymer in Parthenium argentatum Gray

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.92.3.816· OSTI ID:5772608

Benedict, C R; Madhavan, S; Greenblatt, G A; Venkatachalam, K V; Foster, M A ^[1]

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1. Texas A M Univ., College Station (USA)

Washed rubber particles isolated from stem homogenates of Parthenium argentatum Gray by ultracentrifugation and gel filtration on columns of LKB Ultrogel AcA34 contain rubber transferase which catalyzes the polymerization of isopentenyl pyrophosphate into rubber polymer. The polymerization reaction requires Mg{sup 2+} isopentenyl pyrophosphate, and an allylic pyrophosphate. The K{sub m} values for Mg{sup 2+}, isopentenyl pyrophosphate, and dimethylallyl pyrophosphate were 5.2 {times} 10{sup {minus}4} molar, 8.3 {times} 10{sup {minus}5} molar, and 9.6 {times} 10{sup {minus}5} molar, respectively. The molecular characteristics of the rubber polymer synthesized from ({sup 14}C)isopentenyl pyrophosphate were examined by gel permeation chromatography. The peak molecular weight of the radioactive polymer increased from 70,000 in 15 minutes to 750,000 in 3 hours. The weight average molecular weight of the polymer synthesized over a 3 hour period was 1.17 {times} 10{sup 6} compared to 1.49 {times} 10{sup 6} for the natural rubber polymer extracted from the rubber particles. Over 90% of the in vitro formation of the rubber polymer was de novo from dimethylallyl pyrophosphate and isopentenyl pyrophosphate. Treatment of the washed rubber particles with 3-((3-cholamidopropyl) dimethylammonio) -1-propanesulfonate solubilized the rubber transferase. The solubilized enzyme(s) catalyzed the polymerization of isopentenyl pyrophosphate into rubber polymer with a peak molecular weight of 1 {times} 10{sup 5} after 3 hours of incubation with Mg{sup 2+} and dimethylallyl pyrophosphate. The data support the conclusion that the soluble preparation of rubber transferase is capable of catalyzing the formation of a high molecular weight rubber polymer from an allylic pyrophosphate initiator and isopentenyl pyrophosphate monomer.

• OSTI ID: 5772608
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 92:3; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090800 -- Biomass Fuels-- Production-- (1990-)
550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
ELASTOMERS
ENZYME ACTIVITY
ENZYMES
EUPHORBIA
GUAYULE
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MOLECULAR WEIGHT
NATURAL RUBBER
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PLANTS
POLYMERS
REACTION KINETICS
RUBBER TREES
RUBBERS
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
TREES