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Chastain, C.J., Fries, J.P., Vogel, J.A., Randklev, C.L., Vossen, A.P., Dittmer, S.K., Watkins, E.E., Fiedler, L.J., Wacker, S.A., Meinhover, K.C., Sarath, G. and Chollet, R. (2002) Pyruvate, orthophosphate dikinase in leaves and chloroplasts of C3 plants undergoes light-/dark-induced reversible phosphorylation. Plant Physiology, 128, 13681378. doi:10.1104/pp.010806

has been cited by the following article:

• TITLE: Identification of the amino acid involved in the regulation of bacterial pyruvate, orthophosphate dikinase and phosphoenolpyruvate synthetase

  AUTHORS: Rebecca Tolentino, Chris Chastain, Jim Burnell

  KEYWORDS: Escherichia Coli; Listeria Monocytogenes; Enzyme Regulation; Phosphoryla-tion/Dephosphorylation; Pyruvate Orthophosphate Dikinase; PEP Synthetase

  JOURNAL NAME: Advances in Biological Chemistry, Vol.3 No.3A, June 21, 2013

  ABSTRACT: Pyruvate, orthophosphate dikinase (PPDK) and phosphoenolpyruvate synthetase (PEPS) catalyze the conversion of pyruvate to phosphoenolpyruvate (PEP). Both are regulated by a phosphorylation-dephosphorylation mechanism involving a bifunctional serine/ threonine kinase and a pyrophosphorylase (PPDK regulatory protein, PDRP, and PEPS regulatory protein, PSRP, respectively). In plants the regulatory mechanism involves phosphorylation of a threonine residue that is separated by a single amino acid from the histidine residue that forms a phosphorylated intermediate during catalysis. Using antibodies, we demonstrated that the regulation of both Listeria monocytogenes PPDK and Escherichia coli PEP synthetase involves the phosphorylation of a threonine residue located close to the catalytic histidine residue. The amino acid located between the regulatory threonine and the catalytic histidine is highly conserved being serine in PPDK and cysteine in PEPS. Using site-directed mutagenesis we have shown that both PPDK and PEPS in which the serine and cysteine residues, respectively, were substituted with an alanine the enzymes could be regulated indicating that the serine and cysteine residues, respectively, are not essential for regulation. We also demonstrated that altering the intermediate amino acid did not alter the specificity of the regulatory proteins for their protein substrates.