Question

8.

a. Which experimental technique separates proteins based on their relative physical sizes?

1) Ion-exchange chromatography                                                    4) None of the above

2) Affinity chromatography                                                                        5) More than one of the above        

3) Size-exclusion chromatography

b. One round of the sequencing technique called _________ reveals the identity of the amino acid located at the ____________ of a peptide or protein.

1) Trypsin treatment; N-terminus

2) Edman degradation; N-terminus

3) Edman degradation; C-terminus

4) Sanger’s reagent ; C-terminus                

5) Carboxypeptidase treatment; N-terminus                    

c. The following product was found after one round of Edman degradation.

The sequenced peptide must have which one of the following amino acids somewhere in its sequence?

1) D                                                                             4) Q

2) E                                                                             5) None of the above            

3) N

d. Determine the percentage of V_max that an enzyme-catalyzed reaction’s V would be at the following substrate concentration: [S] = ¼K_M. Round your percentage to 1 decimal place. Please do not enter the “%” sign as part of your answer.

e. Determine the percentage of V_max that an enzyme-catalyzed reaction’s V would be at the following substrate concentration: [S] = 20K_M. Round your percentage to 1 decimal place. Please do not enter the “%” sign as part of your answer.

f. You are trying to purify a mixture of proteins using size-exclusion chromatography. The mixture contains 5 proteins, whose lengths (number of amino acids in their sequence) are shown below:

            Protein 1: 88 residues                                               Protein 4: 120 residues

            Protein 2: 135 residues                                Protein 5: 166 residues

            Protein 3: 148 residues

Assume that each protein’s amino acid residues have an average molecular weight of 110. The pore size in the size-exclusion chromatography column’s beads has a molecular weight cutoff of 15,000, meaning that only proteins with a molecular weight that is less than 15,000 can enter the beads.

Given this information, which one option below lists all the proteins that will elute (exit from) the column quickly? Select the correct answer from the choices shown below, and place your answer on the online answer form.

1) Protein 1, Protein 2 4) Protein 3, Protein 5

2) Protein 3, Protein 4 5) None of the above

3) Protein 2, Protein 3, Protein 5

Answer 1

8.a. Which experimental technique separates proteins based on their relative physical sizes?

1) Ion-exchange chromatography                                                    4) None of the above

2) Affinity chromatography                                                                5) More than one of the above        

3) Size-exclusion chromatography

Answer: 3) Size-exclusion chromatography

b. One round of the sequencing technique called_Edman degradation reveals the identity of the amino acid located at the N-terminus of a peptide or protein.

1) Trypsin treatment; N-terminus

2) Edman degradation; N-terminus

3) Edman degradation; C-terminus

4) Sanger’s reagent ; C-terminus                

5) Carboxypeptidase treatment; N-terminus                    

c. The following product was found after one round of Edman degradation.

The sequenced peptide must have which one of the following amino acids somewhere in its sequence?

1) D                                                                             4) Q

2) E                                                                             5) None of the above            

3) N

Answer 5) None of the above

d. Determine the percentage of V_max that an enzyme-catalyzed reaction’s V would be at the following substrate concentration: [S] = ¼K_M. Round your percentage to 1 decimal place. Please do not enter the “%” sign as part of your answer.

Answer: 20

e. Determine the percentage of V_max that an enzyme-catalyzed reaction’s V would be at the following substrate concentration: [S] = 20K_M. Round your percentage to 1 decimal place. Please do not enter the “%” sign as part of your answer.

Answer: 95.2

f. You are trying to purify a mixture of proteins using size-exclusion chromatography. The mixture contains 5 proteins, whose lengths (number of amino acids in their sequence) are shown below:

            Protein 1: 88 residues                                  Protein 4: 120 residues

            Protein 2: 135 residues                                Protein 5: 166 residues

            Protein 3: 148 residues

Assume that each protein’s amino acid residues have an average molecular weight of 110. The pore size in the size-exclusion chromatography column’s beads has a molecular weight cutoff of 15,000, meaning that only proteins with a molecular weight that is less than 15,000 can enter the beads.

Given this information, which one option below lists all the proteins that will elute (exit from) the column quickly? Select the correct answer from the choices shown below, and place your answer on the online answer form.

1) Protein 1, Protein 2 4) Protein 3, Protein 5

2) Protein 3, Protein 4 5) None of the above

3) Protein 2, Protein 3, Protein 5

Answer: 4) Protein 3, Protein 5