Point EPSP synthase

In resistant accessions of Eleusine indica from Malaysia it was found to be due to point mutations of the target enzyme EPSP synthase. By PCR amplification and sequence analysis of an EPSP synthase fragment an exchange of Prol06 by Ser was found in two resistant accessions, and an exchange of Prol06 by Thr in a third resistant accession [62]. 

The information obtained from the application of glyphosate to complex systems strongly pointed to one of the following three enzymes as the target of the inhibitor in the shikimate pathway shikimate kinase (EC 2.7.1.71), 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase (EC 2.5.1.19), and chorismate synthase (EC 4.6.1.4). Jointly, these three enzymes convert shikimic acid to chorismic acid in a series of interesting reactions >(Fig. 2). A defined system" had therefore to be found in which the conversion of shikimic acid to chorismic acid could be conveniently studied. 

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