High-yield purification of glucokinase from rat liver.

A rapid and reliable method for the purification of rat liver glucokinase was developed. The procedure consists of DEAE-cellulose ion-exchange chromatography, Phenyl-Sepharose hydrophobic interaction chromatography, DEAE-Affi Gel Blue dye-ligand chromatography, and duplicate steps of glucosamine-Sepharose affinity chromatography. Glucokinase was purified to a specific activity of 290 units/mg protein in a yield of 55% in 6 days. The final enzyme preparations were completely homogeneous in most experiments as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The estimated molecular weight (51,000) and sigmoidal saturation function for glucose of purified glucokinase were in good agreement with published data.