Chapter 15, Problem 25P

Interpretation Introduction

Interpretation:

The ratio of $\left(\text{B/A}\right)$ under cellular condition is to be calculated.

Concept introduction:

ATP is a nucleotide that consists of adenine, ribose and a triphosphate unit.

When ATP is hydrolyzed to adenine monophosphate and pyrophosphate, a large amount of energy is liberated.

A can be converted into B under these conditions if the reaction is coupled to the hydrolysis of ATP. The overall reaction is as follows:

$\text{A}+\text{ATP}+{\text{H}}_{\text{2}}\text{O}\to \text{B}+\text{ADP}+\text{Pi}$

The equilibrium constant expression for the coupled reaction is as follows:

$K_{\text{eq}}^{\text{'}}=\left(\frac{{\left[\text{B}\right]}_{\text{eq}}}{{\left[\text{A}\right]}_{\text{eq}}}\right)\left(\frac{{\left[\text{ADP}\right]}_{\text{eq}}{\left[{\text{P}}_1\right]}_{\text{eq}}}{{\left[\text{ATP}\right]}_{\text{eq}}}\right)$   ....... (1)

Where,

• $K_{\text{eq}}^{\text{'}}$ is the equilibrium constant.
• ${\left[\text{B}\right]}_{\text{eq}}$ is the concentration of B at equilibrium.
• ${\left[\text{A}\right]}_{\text{eq}}$ is the concentration of A at equilibrium.
• ${\left[\text{ADP}\right]}_{\text{eq}}$ is the concentration of ADP at equilibrium.
• ${\left[\text{ATP}\right]}_{\text{eq}}$ is the concentration of ATP at equilibrium.
• ${\left[{\text{P}}_1\right]}_{\text{eq}}$ is the concentration of ${\text{P}}_1$ at equilibrium.