Chapter 21, Problem 77P

Interpretation Introduction

(a)

Interpretation:

The optimum pH for enzyme 'A' needs to be determined, using the given pH versus enzyme activity graph for enzyme A and B.

Concept Introduction:

Enzymes are defined as a biological catalyst for various reactions in the living organisms. Enzymes are like all catalyst as it also increases the rate reaction but they themselves do not changed permanently during the process. Enzyme does not alter the position of equilibrium and the relative energy of both the reactant and the products. Reaction when catalyzed by an enzyme increases the rate of reaction by ${10}^6\text{to}{10}^{12}$ times faster than a similar uncatalyzed reaction. Enzymes are specific in nature.

Answer to Problem 77P

Optimum pH for enzyme 'A' is $6$.

Explanation of Solution

The activity of enzyme is affected by both the temperature and pH. By increasing temperature, rate of reaction also increases until its maximum activity occurs that is at $37°\text{C}$ , after that the activity of enzyme decreases rapidly. Enzymes denatured at high temperature. The enzyme's activity destroyed at $50-60°\text{C}$ . At optimum pH $\left(7.4\right)$ the rate of enzyme catalyzed reaction is maximum but for some enzymes like pepsin has optimum pH of 2.

Optimum pH is the pH at which the activity of an enzyme is maximum. So, from the given graph, the activity of enzyme A is maximum at pH 6. Hence the optimum pH of enzyme A is 6.

Interpretation Introduction

(b)

Interpretation:

The optimum pH for enzyme 'B' needs to be determined, using the given pH versus enzyme activity graph for enzyme A and B.

Concept Introduction:

Enzymes are defined as a biological catalyst for various reactions in the living organisms. Enzymes are like all catalyst as it also increases the rate reaction but they themselves do not changed permanently during the process. Enzyme does not alter the position of equilibrium and the relative energy of both the reactant and the products. Reaction when catalyzed by an enzyme increases the rate of reaction by ${10}^6\text{to}{10}^{12}$ times faster than a similar uncatalyzed reaction. Enzymes are specific in nature.

Answer to Problem 77P

Optimum pH for enzyme 'B' is $10$.

Explanation of Solution

The activity of enzyme is affected by both the temperature and pH. By increasing temperature, rate of reaction also increases until its maximum activity occurs that is at $37°\text{C}$ , after that the activity of enzyme decreases rapidly. Enzymes denatured at high temperature. The enzyme's activity destroyed at $50-60°\text{C}$ . At optimum pH $\left(7.4\right)$ the rate of enzyme catalyzed reaction is maximum but for some enzymes like pepsin has optimum pH of 2.

Optimum pH is the pH at which the activity of an enzyme is maximum. So, from the given graph, the activity of enzyme B is maximum at pH 10.

Hence, the optimum pH of enzyme B is 10.

Interpretation Introduction

(c)

Interpretation:

The enzyme having the higher activity when pH is $4$ needs to be determined, using the given pH versus enzyme activity graph for enzyme A and B.

Concept Introduction:

Enzymes are defined as a biological catalyst for various reactions in the living organisms. Enzymes are like all catalyst as it also increases the rate reaction but they themselves do not changed permanently during the process. Enzyme does not alter the position of equilibrium and the relative energy of both the reactant and the products. Reaction when catalyzed by an enzyme increases the rate of reaction by ${10}^6\text{to}{10}^{12}$ times faster than a similar uncatalyzed reaction. Enzymes are specific in nature.

Answer to Problem 77P

Enzyme 'A' will have higher pH at $4$.

Explanation of Solution

The activity of enzyme is affected by both the temperature and pH. Optimum pH is the pH value at which the enzyme is most active. The rate of enzyme catalyzed reaction is maximum at optimum pH $\left(7.4\right)$ is an optimum pH for most of the enzymes. Enzymes extremely at high or low pH values generally results in loss of activity.

The graph shown below clearly explains the activity of an enzyme with change in pH values:

From the given graph, it can be seen that the activity of enzyme B starts from pH 6 onwards and activity of enzyme A starts from pH 2 onwards. So, before pH 2 enzyme A is inactive and before pH 6 enzyme B is inactive. Therefore, at pH 4 the activity of enzyme A is higher than that of enzyme B.

Interpretation Introduction

(d)

Interpretation:

The enzyme having the higher activity at pH $9$ needs to be determined, using the given pH versus enzyme activity graph for enzyme A and B.

Concept Introduction:

Enzymes are defined as a biological catalyst for various reactions in the living organisms. Enzymes are like all catalyst as it also increases the rate reaction but they themselves do not changed permanently during the process. Enzyme does not alter the position of equilibrium and the relative energy of both the reactant and the products. Reaction when catalyzed by an enzyme increases the rate of reaction by ${10}^6\text{to}{10}^{12}$ times faster than a similar uncatalyzed reaction. Enzymes are specific in nature.

Answer to Problem 77P

Enzyme 'B' will have the higher activity at pH $9$.

Explanation of Solution

The activity of enzyme is affected by both the temperature and pH. Optimum pH is the pH value at which the enzyme is most active. The rate of enzyme catalyzed reaction is maximum at optimum pH $\left(7.4\right)$ is an optimum pH for most of the enzymes. Enzymes extremely at high or low pH values generally results in loss of activity.

The graph shown below clearly explains the activity of an enzyme with change in pH values:

From the given graph, it can be seen that the activity of enzyme B starts from pH 6 onwards and becomes maximum at pH 10and then activity of enzyme starts decreasing. And activity of enzyme A starts from pH 2 onwards and becomes maximum at pH 6 and then starts decreasing.

At pH 9, activity of enzyme A is decreasing and that of enzyme B is increasing. Hence, at pH 9 activity of enzyme B is higher than that of enzyme A.