Enolpyruvyl shikimate-3-phosphate synthase (EC 2.5.1.19) was purified to near homogeneity (-90% purity) from Klebsiella pneumoniae. Glyphosate, a herbicide, competitively inhibits with phosphoenolpyruvate (PEP) with Ki =M. An analogue of shikimate 3-phosphate, 4,5-dideoxyshikimate 3-phosphate (ddS3P), competitively inhibits with shikimate 3-phosphate with K, = M. The enzyme is inactivated by 3-bromopyruvate. T I l 2 for inactivation is approximately 5 min at 0.15 mM 3-bromopyruvate. PEP protects against inactivation by 3-bromopyruvate, while ddS3P alone has no effect on the rate of inactivation. The protective effect of PEP is enhanced approximately 16-fold in the presence of ddS3P. The enzyme catalyzes exchange of solvent 3H into PEP in the presence of ddS3P but not in its absence.

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