Data Are Plotted for the Action of a Histone-Modifying Enzyme

Multiple Choice

Data are plotted for the action of a histone-modifying enzyme (solid lines) in two graph formats in Figure 4.10.Dashed lines indicate the data for the enzyme in the presence of an effector molecule, deoxycytidine triphosphate (dCTP) . Which statement is not true regarding this enzyme, its substrate (histone protein) , and its effector dCTP?

A) The effector dCTP increases the Km.
B) The enzyme is under allosteric control.
C) The influence of the effector is reduced at high substrate (histone) concentrations.
D) The enzyme obeys Michaelis-Menten kinetics.
E) dCTP is an inhibitory effector of enzyme activity.