Enzyme Kinetics-L2

Question 1

What is the difference between a slave and regulatory enzyme?

Answer 1

Slave enzyme- controlled purely by its environment

Regulatory enzyme- activity/inactivity is increased or decreased by specific mechanisms

Question 2

Name the factors that control enzymes:

Answer 2

• temperature
• ph (most impact upon the enzyme)
• enzyme conc.
• substrate conc.
• inhibitors

Question 3

Define the Km and describe how it indicates the affinity of an enzyme for its substrate:

Answer 3

Km= [substrate] @ which a half Vmax is reached

- high Km means low affinity for substrate

Question 4

Define the Vmax

Answer 4

Vmax= [substrate] is in excess and enzyme is operating at its full capacity

Question 5

How do you work out the Km and Vmax from lineweaver burk plot?

Answer 5

Km = -  1/ x-intercept
Vmax = 1/ y-intercept

Question 6

What is meant by zero order kinetics?

Answer 6

[substrate] is far in excess

Question 7

What is meant by the term first order kinetics?

Answer 7

[substrate] is limiting

Question 8

What are the conditions required for a valid enzyme assay?

Answer 8

• substrate should be about 10 to 50 times Km