Gateway Technical College

BIO 806-177

Lecture 5 : Protein Characterization

1)Which of the following experimental methods can NOT be used for protein purification:

1. 1. Affinity Chromotography
   2. Tandem Mass Spectrometry
   3. Ion Exchange Chromotography
   4. Gel Filtration
2. You have a solution containing a mixture of 3 proteins:

1. 100 Kda protein w/ pI = 3
2. 100 Kda protein w/ pI = 7
3. 100 Kda protein w/ pI = 11 How would you purify protein (iii)?
   1. Run a gel filtration column, and take the first band
   2. Run an anion exchange column at pH = 9 and take the earliest elution
   3. Run a gel filtration column, and take the last band
   4. Run a cation exchange column at pH = 9 and take the earliest elution

3. In size exclusion chromatography, smaller proteins elute through the column:
   1. Slower than larger proteins
   2. Faster than larger proteins
   3. At the same speed as larger proteins
   4. There is not enough information to answer this question
4. A protein of interest is bound to the matrix of a cation exchange column. Which of the following techniques would successfully elute this protein from the column?

1. Increase pH above the protein’s pI
2. Decrease the pH below the protein’s pI
3. Addition of an ionic salt to the elution buffer
   1. (i) only
   2. (ii) only
   3. (iii) only
   4. both (i) and (iii)
   5. both (ii) and (iii)

5. Which of the following methods is commonly used for determining the sequence of a purified protein?
   1. Affinity chromatography
   2. Ion Exchange chromatography
   3. Gel Filtration
   4. Tandem Mass Spectrometry
6. A (His)6- tagged protein is bound to the matrix of a nickel column. Which of the following methods can be used to elute the protein from the column?

1. Run a high pH buffer through the column
2. Run a low pH buffer through the column
3. Run an imidazole-containing buffer through the column
4. Run a urea-containing buffer through the column
   1. (i) only
   2. (ii) only
   3. (i) or (iii)
   4. (ii) or (iii)
   5. (ii), (iii), or (iv)