The presence of multiple hexokinase isozymes (I–IV) for the phosphorylation of glucose enables specific organs to regulate carbohydrate metabolism in a unique way. Hexokinase IV, also called glucokinase, represented by the blue curve in the plot, is the predominant isozyme in liver. Hexokinase IV has distinct kinetic properties from the other hexokinase isozymes, which are represented by the red curve. Note the difference in the shapes of the curves within the physiological range of glucose concentration