Question 1

In the Edman degradation analysis of the N-terminus of a peptide the terminal residue reacts with phenyl isocyanate, an example is shown below. Provide the structure of both of the products of this reaction.

Accepted Answer

The answer of In the Edman degradation analysis of the...

Question 2

What fragments are produced when porcine dynorphin, a peptide that contains 17 amino acid residues (shown below), is cleaved with trypsin?
Tyr−Gly−Gly−Phe−Leu−Arg−Arg−Ile−Arg−Pro−Lys−Leu−Lys−Trp−Asp−Asn−Gln

Accepted Answer

The answer of What fragments are produced when porcine dynorphin,...

Question 3

Edman degradation of the peptide saralasin shows that it has a sarcosine residue at the N-terminus.
Sarcosine is  Partial hydrolysis of saralasin with dilute hydrochloric acid gives the following fragments:
His−Pro−Ala
Val−Tyr−Val
Arg−Val−Tyr
Sar−Arg−Val
Tyr−Val−His
What is the structure of saralasin?

Accepted Answer

The answer of Edman degradation of the peptide saralasin shows...

Question 4

Identify the compound shown below. ​

Accepted Answer

The answer of Identify the compound shown below. ​ 
...

Question 5

Which of the following is not a strategy for the synthesis of polypeptides?

Accepted Answer

B describes a method for determining the sequence of a polypeptide, not a strategy for synthesizing polypeptides. Choices A, C, and D are actual strategies used in the synthesis process to protect reactive groups and activate others for controlled reaction.

Question 6

Provide the structure of Ser-Ala.

Accepted Answer

The answer of Provide the structure of Ser-Ala....

Question 7

Provide the structure of Ser-Phe-Asp.

Accepted Answer

The answer of Provide the structure of Ser-Phe-Asp....

Question 8

Identify the function of the following group in protein synthesis. ​

Accepted Answer

The answer of Identify the function of the following group...

Question 9

The combination of the two sidechains of the given compounds leads to the formation of a special bond. Identify the type of bond formed. ​

Accepted Answer

The answer of The combination of the two sidechains of...

Question 10

Provide the structure of dicylcohexylcarbodiimide, a common reagent that is used to couple two amino acid residues by formation of a peptide bond, and the structure N,N'-dicyclohexylurea, the byproduct of this reaction.

Accepted Answer

The answer of Provide the structure of dicylcohexylcarbodiimide, a common...

Question 11

What fragments are produced when porcine dynorphin, a peptide that contains 17 amino acid residues (shown below), is cleaved with chymotropsin?
Tyr−Gly−Gly−Phe−Leu−Arg−Arg−Ile−Arg−Pro−Lys−Leu−Lys−Trp−Asp−Asn−Gln

Accepted Answer

The answer of What fragments are produced when porcine dynorphin,...

Question 12

What are the products of the reaction of alanine and ninhydrin (shown below)?

Accepted Answer

The answer of What are the products of the reaction...

Question 13

Which of the following is not an endopeptidase?

Accepted Answer

Carboxypeptidase A is not an endopeptidase; it is an exopeptidase that cleaves amino acids from the carboxyl end of proteins, whereas trypsin, chymotrypsin, and elastase are endopeptidases that cleave peptide bonds within the protein chain.

Question 14

In the case of paper electrophoresis, a paper strip saturated with an aqueous buffer of predetermined pH serves as a bridge between the two _____.

Accepted Answer

The answer of In the case of paper electrophoresis, a...

Question 15

Identify the technique that has almost replaced the automated Edman degradation.

Accepted Answer

Mass spectrometry has almost replaced the automated Edman degradation for protein sequencing due to its speed, sensitivity, and ability to analyze very small amounts of sample.

Question 16

Disulfide bonds form between the thiol side chains of cysteine. What is the best term to describe the reaction of two thiols to give a disulfide bond?

Accepted Answer

The answer of Disulfide bonds form between the thiol side...

Question 17

Provide the major organic product of the following reaction that is used in the chemical synthesis of peptides.

Accepted Answer

The answer of Provide the major organic product of the...

Quiz 27: Amino Acids and Proteins