• Kinetic analysis of gluconate phosphorylation by human gluconokinase using isothermal titration calorimetry.

      Rohatgi, Neha; Guðmundsson, Steinn; Rolfsson, Óttar; Univ Iceland, Ctr Syst Biol, IS-101 Reykjavik, Iceland, Univ Iceland, Biomed Ctr, IS-101 Reykjavik, Iceland (Elsevier Science BV, 2015-11-30)
      Gluconate is a commonly encountered nutrient, which is degraded by the enzyme gluconokinase to generate 6-phosphogluconate. Here we used isothermal titration calorimetry to study the properties of this reaction. ΔH, KM and kcat are reported along with substrate binding data. We propose that the reaction follows a ternary complex mechanism, with ATP binding first. The reaction is inhibited by gluconate, as it binds to an Enzyme-ADP complex forming a dead-end complex. The study exemplifies that ITC can be used to determine mechanisms of enzyme catalyzed reactions, for which it is currently not commonly applied.