Carbonic Anhydrase Has Two Substrates, Carbon Dioxide and Bicarbonate, Which

Multiple Choice

Carbonic anhydrase has two substrates, carbon dioxide and bicarbonate, which are both converted to carbonic acid. Kinetic data for each is given below. While determining the kinetics of HCO₃^- as a substrate, how would the addition of CO₂ effect the reaction if the rate were measured by the disappearance of bicarbonate?
Substrate
K_m (mM)
K_cat (sec^-1)
K_cat/K_m (m M^-1sec^-1)
CO₂
HCO₃^-
12
26
1×10⁶
4×10⁵
8) 3×10⁴
1.5×10⁴

A) CO₂ would increase the activity of the enzyme
B) CO₂ would cause an apparent decrease in the K_m for HCO₃^-
C) CO₂ would act as a noncompetitive inhibitor
D) CO₂ would act as a competitive inhibitor
E) none of the above