Phosphate Analogues as Probes of the Catalytic Mechanisms of MurA and AroA, Two Carboxyvinyl Transferases †

The role in catalysis of phosphate with AroA (enolpyruvyl shikimate 3-phosphate synthase) and MurA (enolpyruvyl UDP-GlcNAc synthase) was probed using phosphate analogues and an AroA mutant. Phosphate, the second reaction product, increases the reactivity of the enolpyruvyl products (EP-OR's) approximately 10(5)-fold in the reverse reaction, forming phosphoenolpyruvate and R-OH (shikimate 3-phosphate or UDP-GlcNAc). Phosphate is intrinsically …