The direct synthesis of phospho enol pyruvate from pyruvate by Escherichia coli

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Abstract
Extracts of Escherichia coli are shown to contain an enzyme system which in the presence of Mg$^{2+}$ catalyses the direct formation of phosphoenolpyruvate from pyruvate and ATP with concomitant formation of AMP and inorganic phosphate. This enzyme, which has been designated 'phosphoenolpyruvate synthase' (PEP-synthase) has been purified 80-fold and is free of pyruvate kinase activity; PEP synthesis proceeded most rapidly at pH 8 to 8$\cdot $5. At pH values between 6$\cdot $2 and 7$\cdot $5 the enzyme can catalyse the formation of ATP and pyruvate from PEP, AMP and inorganic phosphate; if arsenate is used instead of phosphate, pyruvate and ADP are produced instead. Studies of the enzymic formation of PEP with ATP specifically labelled with $^{32}$P, and of the reverse reaction with [U-$^{14}$C]AMP, suggest that the PEP-synthase reaction involves the transfer of a pyrophosphoryl-group. The physiological role of PEP-synthase has been demonstrated with mutants of E. coli devoid of the enzyme: in contrast to wild-type organisms, such mutants neither grow on pyruvate, lactate or alanine, nor form glycogen from lactate. It is thus concluded that PEP-synthase plays an important role in the anaplerotic and the biosynthetic reactions which enable the organisms to grow on pyruvate as sole carbon source.

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