5-enolpyruvylshikimate 3-phosphate synthase, the target enzyme of the herbicide glyphosate, is synthesized as a precursor in a higher plant.
Cell cultures of Corydalis sempervirens adapted to growth in the presence of 5 millimolar glyphosate overproduce the herbicide's target enzyme, 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, 30- to 40-fold. In vitro translation of total RNA and poly(A)-RNA coupled with immunoprecipitation showed that the protein is synthesized as a precursor of relative molecular weight (M(r)) 53900 +/- 900 as compared to M(r) 45500 +/- 1000 of the mature enzyme. Translatable activity of mRNA for EPSP-synthase in glyphosate-adapted cultures is tenfold higher than in nonadapted cultures.
Holländer-Czytko
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Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität Bochum, D 4630 Bochum, Federal Republic of Germany.
Amrhein
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