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

A thermoresistant gluconokinase encoded by the gntK gene of Escherichia coli K-12 was purified and characterized. The Km values of the purified enzyme for gluconate and ATP are 42 microM and 123 microM, 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. Istúriz (1994) J. Basic. Microbiol. 16, 117-122.