?
Phosphoenolpyruvate carboxykinase (PEPCK), a critical gluconeogenic enzyme, catalyzes the first committed step in the diversion of tricarboxylic acid cycle intermediates toward gluconeogenesis. It catalyzes the reversible decarboxylation and phosphorylation of oxaloacetate to yield phosphoenolpyruvate and carbon dioxide, using a nucleotide molecule (ATP or GTP) for the phosphoryl transfer, and has a strict requirement for divalent metal ions for activity. PEPCK's separate into two phylogenetic groups based on their nucleotide substrate specificity (the ATP-, and GTP-dependent groups).HprK/P, the bifunctional histidine-containing protein kinase/phosphatase, controls the phosphorylation state of the phosphocarrier protein HPr and regulates the utilization of carbon sources by gram-positive bacteria. It catalyzes both the ATP-dependent phosphorylation of HPr and its dephosphorylation by phosphorolysis. PEPCK and the C-terminal catalytic domain of HprK/P are structurally similar with conserved active site residues suggesting that these two phosphotransferases have related functions.
Jiyao W et al.(2023). "The conserved domain database in 2023.",