Chapter 6, Problem 63TQ

Summary Introduction

To analyze:

Calculation of $k_{cat}$ / $K_m$, where k_cat is the turnover number and $K_m$ is the Michaelis–Menten constant. Determine the alcoholeasily metabolized by alcohol dehydrogenase using the data given in the table:

Substrate	$K_m$ ( $\mu$ M)	$k_{cat}$ ( ${\min }^{-1}$ )
Ethanol	960	480
1-butanol	440	450
1-hexanol	69	182
12-hydroxydodecanoate	50	146
All-trans-retinol	20	78
Benzyl alcohol	410	82
2-butanol	250000	285
cyclohexanol	31000	122

Introduction:

$K_m$ and $k_{cat}$ values are important to determine the activity of an enzyme and the rate of reaction. $k_{cat}$ refers to the number of the substratemolecules that areconverted into product, per unit time. $K_m$ isMichaelis–Mentenconstant. It represents the binding affinity of the substrate with the enzyme. The binding affinity of the enzymeis higher if the value of $K_m$ is lower. Collectively, $K_m$ and $k_{cat}$ are referred to as specificity constant.