Regulation of C4 photosynthesis: identification of a catalytically important histidine residue and its role in the regulation of pyruvate,Pi dikinase

Arch Biochem Biophys. 1984 May 15;231(1):175-82. doi: 10.1016/0003-9861(84)90375-8.


These studies provide further information regarding the mechanism of the light/dark-mediated regulation of pyruvate,Pi dikinase in leaves. It is shown that a catalysis-linked phosphorylation of pyruvate,Pi dikinase can be demonstrated following incubation of the enzyme with [32P]phosphoenolpyruvate or [beta-32P]ATP plus Pi, that the enzyme-bound phosphate is located on a histidine residue, and that this phosphate is retained during ADP-mediated inactivation. Further evidence is provided that phosphorylation of this histidine is a prerequisite for ADP-mediated inactivation through phosphorylation of a threonine residue from the beta-phosphate of ADP. It is demonstrated that diethylpyrocarbonate (which forms a derivative with histidine residues) prevents [32P]phosphoenolpyruvate-dependent labeling (catalytic labeling) and [beta-32P]ADP-dependent labeling (inactivation labeling) of the enzyme. In addition, it is demonstrated that oxalate, an analog of pyruvate, competitively inhibits ADP-dependent inactivation with respect to ADP. The significance of these results is discussed with regard to the mechanism of regulation of pyruvate,Pi dikinase in vivo.

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Amino Acids / analysis
  • Binding Sites
  • Catalysis
  • Chemical Phenomena
  • Chemistry
  • Diethyl Pyrocarbonate / pharmacology
  • Histidine / isolation & purification*
  • Histidine / metabolism
  • Oxalates / pharmacology
  • Oxalic Acid
  • Phosphorylation
  • Phosphotransferases / metabolism*
  • Photochemistry
  • Pyruvate, Orthophosphate Dikinase / metabolism*
  • Zea mays / enzymology


  • Amino Acids
  • Oxalates
  • Histidine
  • Adenosine Diphosphate
  • Oxalic Acid
  • Phosphotransferases
  • Pyruvate, Orthophosphate Dikinase
  • Diethyl Pyrocarbonate