Question

L-Arabinose is a naturally occurring, non-caloric sweetener that is a non-competitive inhibitor of sucrase. If L-Arabinose is present, what will happen to the Vmax of the reaction and Km of the substrate?

a) Vmax and Km will both increase
b) Vmax and Km will both decrease
c) Vmax will not change, but Km will decrease
d) Vmax will decrease, but Km will not change
e) Vmax will decrease, and Km will increase

Answer 1

Vmax is the highest rate of reaction of an enzyme catalyzed reaction and Km is the concentration of substrate required to achieve half of Vmax.

Because there is an inhibitor, Vmax will decrease; however, due to the non-competitive nature of the inhibitor, concentration of the substrate will not make a difference so Km will be unchanged.

The answer is C.