Chapter 4: Q34P (page 96)

What is the approximate net charge of carnosine (a) at pH 3, (b) pH 5,
(c) pH 7, and (d) pH 9?

Short Answer

Expert verified

a) At $pH$ 3 = +1

b At $pH$ 5 = +1

c) At $pH$ 7 = 0

d) At $pH$ 9 = -1/2

Step by step solution

Carnosine-amino acid

Carnosine is a powerful antioxidant commonly found in proteins. It is composed of two amino acids, beta-alanine, and histidine. Thus, it is a dipeptide molecule because of these two amino acids combination.

Net charge at different

To determine the net charge on amino acid, three conditions is given below:

$\begin{array}{l} {1)pH<pK}_{a} \to protonated \\ {2)pH>pK}_{a} \to deprotonated \\ {3)pH=pK}_{a} \to \frac{1}{2} protonated, \frac{1}{2} deprotonated \end{array}$

Carnosine structure with its ${pK}_{a}$ values are given below:

From the given pK_a values, net charge of carnosine can be calculated.

Each ionizing group adds all charges at a given pH to get a net charge.

$\begin{array}{l} pHAminoCarboxylicimidazoleNetcharge \\ groupgroupring \\ 3+1-1+1+1 \\ 5+1-1+1+1 \\ 70-1+10 \\ 90-1+ \frac{1}{2} - \frac{1}{2} \end{array}$

Hence, the net charge of carnosine at different $pH$ is calculated.

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What is the approximate net charge of carnosine (a) at pH 3, (b) pH 5,
(c) pH 7, and (d) pH 9?

Short Answer

Step by step solution

Carnosine-amino acid

Net charge at different

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What is the approximate net charge of carnosine (a) at pH 3, (b) pH 5,(c) pH 7, and (d) pH 9?

Short Answer

Step by step solution

Carnosine-amino acid

Net charge at different

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Biology Textbooks

Communicable Diseases

Organ Systems

Biological Structures

Plant Biology

Bioenergetics

Cellular Energetics

Study anywhere. Anytime. Across all devices.

What is the approximate net charge of carnosine (a) at pH 3, (b) pH 5,
(c) pH 7, and (d) pH 9?