Glucose taken up by liver cells is rapidly phosphorylated to glucose 6-phosphate by ATP in the initial step of metabolism of the sugar. Two enzymes, which may be considered isozymes, are capable of catalyzing this reaction in the liver cell. Hexokinase has a low Km of ~0.05 mM for glucose, whereas glucokinase exhibits a Km of ~5 mM. After a meal, which of the following scenarios best describes the relative activity levels for the two enzymes? Hexokinase Glucokinase
A) not active not active
B) Vo = Vmax/2 not active
C) Vo = Vimax Vo =Vmax
D) Vo = Vmax/2 Vo = Vmax/2
E) Vo = Vmax Vo = Vmax/2