Chemistry 2710 Spring 2000 Quiz 8

Name:

The enzyme carbonic anhydrase catalyzes both directions of the reaction

$$\mathrm{H_2O_{(l)}} + \mathrm{CO_{2(aq)}} \rightleftharpoons \mathrm{H_2CO_{3(aq)}}.$$

A study of the conversion of carbon dioxide to carbonic acid by a 2.32nmol/L solution of carbonic anhydrase yielded the following initial rate data:

[CO2] (mmol/L)	1.25	2.50	5.00	20.00
v ( $\mathrm{mol\,L^{-1}s^{-1}}$)	$2.78\times 10^{-5}$	$5.00\times 10^{-5}$	$8.33\times 10^{-5}$	$1.66\times 10^{-4}$

Calculate K_M and k_-2 (the rate constant for the step $\mathrm{C}\rightarrow\mathrm{E}+\mathrm{P}$) for this enzyme.

Note: Drawing a graph is optional.