Chapter 27, Problem 27.37P

(a)

Interpretation Introduction

Interpretation:

At what $\text{pH}$ an electrophoresis can be carried out to separate the amino acids in the mixture Ala, His, Lys.

Concept Introduction:

The paper electrophoresis is the technique which is used for the separation of amino acids.  In this technique, a paper strip coated with a buffer whose $\text{pH}$ is predetermined is placed between the two electrodes.  When the sample is placed and the electrical potential is applied, the positively charged amino acids moves towards the negative electrode and the negatively charged amino acids moves towards the positive electrode.  After separation, the paper strip is dried and sprayed with the dye to make the separated amino acids visible.

The isoelectric point ($\text{pI}$) of an amino acid is said to be $\text{pH}$ at which the molecules in the amino acid solution have net charge zero.  At isoelectric point, the Zwitter ion form of amino acids is more prominent.

When $\text{pH}$ of the amino acid is greater than $\text{pI}$ of the amino acid, it has a net negative charge.  When $\text{pH}$ of the amino acid is lesser than $\text{pI}$ of the amino acid, it has net positive charge.

(b)

Interpretation Introduction

Interpretation:

At what $\text{pH}$ an electrophoresis can be carried out to separate the amino acids in the mixture Glu, Gln, Asp.

Concept Introduction:

The paper electrophoresis is the technique which is used for the separation of amino acids.  In this technique, a paper strip coated with a buffer whose $\text{pH}$ is predetermined is placed between the two electrodes.  When the sample is placed and the electrical potential is applied, the positively charged amino acids moves towards the negative electrode and the negatively charged amino acids moves towards the positive electrode.  After separation, the paper strip is dried and sprayed with the dye to make the separated amino acids visible.

The isoelectric point ($\text{pI}$) of an amino acid is said to be $\text{pH}$ at which the molecules in the amino acid solution have net charge zero.  At isoelectric point, the Zwitter ion form of amino acids is more prominent.

When $\text{pH}$ of the amino acid is greater than $\text{pI}$ of the amino acid, it has a net negative charge.  When $\text{pH}$ of the amino acid is lesser than $\text{pI}$ of the amino acid, it has net positive charge.

(c)

Interpretation Introduction

Interpretation:

At what $\text{pH}$ an electrophoresis can be carried out to separate the amino acids in the mixture Lys, Leu, Tyr.

Concept Introduction:

The paper electrophoresis is the technique which is used for the separation of amino acids.  In this technique, a paper strip coated with a buffer whose $\text{pH}$ is predetermined is placed between the two electrodes.  When the sample is placed and the electrical potential is applied, the positively charged amino acids moves towards the negative electrode and the negatively charged amino acids moves towards the positive electrode.  After separation, the paper strip is dried and sprayed with the dye to make the separated amino acids visible.

The isoelectric point ($\text{pI}$) of an amino acid is said to be the $\text{pH}$ at which the molecules in the amino acid solution have net charge zero.  At isoelectric point, the Zwitter ion form of amino acids is more prominent.

When the $\text{pH}$ of the amino acid is greater than the $\text{pI}$ of the amino acid, it has a net negative charge.  When $\text{pH}$ of the amino acid is lesser than the $\text{pI}$ of the amino acid, it has net positive charge.