Isolation and characterization of enzymes

Question 1

What is the primary aim of crystallization of an enzyme?

Answer 1

Purification of the protein or preparation of a product suitable for structural studies

Question 2

What method is used for the purification of proteins during crystallization?

Answer 2

Decrease in solubility of proteins in ammonium sulfate solution with an increase in temperature

Question 3

At what temperature are proteins extracted with ammonium sulfate solutions?

Answer 3

At or near 0°

Question 4

What happens to contaminating proteins when extracting with ammonium sulfate?

Answer 4

They are soluble at higher concentrations of ammonium sulfate and are extracted first

Question 5

What indicates the beginning of crystallization in enzyme extracts?

Answer 5

Appearance of turbidity

Question 6

What is the silky sheen observed in crystalline enzymes often referred to?

Answer 6

Schlieren

Question 7

How quickly can crystallization occur after transferring the extract to room temperature?

Answer 7

Within minutes or may require an hour or overnight incubation

Question 8

True or False: The silky sheen is usually evident in the first few hours of crystallization.

Answer 8

False

Question 9

Fill in the blank: The extraction of protein involves using ammonium sulfate solutions of _______ concentration.

Answer 9

Decreasing