Purification and characterization of the Escherichia coli thermoresistant gluconokinase encoded by the gntK gene

A thermoresistant gluconokinase encoded by the gutK gene of Escherichia coli K-12 was purified and characterized. The K-m values of the purified enzyme for gluconate and ATP are 42 mu M and 123 mu M, respectively, and the activity was not altered by the presence of pyruvate, The enzyme was shown to function as a dimer with two identical subunits of 18.4 kDa. These characteristics appear to be distinct from those of the gluconokinase reported by E.I. Vivas, A, Liendo, K. Dawidowicz, and T. Isturiz (1994) J. Basic, Microbiol. 16, 117-122.