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.