Enzyme Kinetics

Question 1

What is the shape of the graph plotted of reaction rate against substrate concentration?
How do we estimate Km using this?

Answer 1

Hyperbolic graph and then levels out

Km is the substate concentration at half the Vmax

Question 2

What is the Michealis - Menton equation regulated by?

What rule must there be for it to work?

Answer 2

Kinetic constants

K-1»>K2

Question 3

What are 3 assumptions we must have?

Answer 3

• concentration of substate is much larger than that of the enzyme so the amount of substrate bound by an enzyme is always small
• Enzyme substate concentration does not change with time
• Initial velocities must be used

Question 4

What is the equation for MM?

Answer 4

Initial velocity = Vmax[S] / Km + [S]

Question 5

When the MM is plotted, what shape is it and what kinetic value does it tend towards?

Answer 5

Hyperbolic and it tends towards Vmax

Question 6

The lower the Km, the — the affinity?

Answer 6

Higher

Question 7

What does the Kcat mean?

Answer 7

The turnover number of substrates to products over time

Question 8

What do competitive inhibitors alter and not alter?

Answer 8

Alter the Km value but not the Vmax

Question 9

What do non-competitive inhibitors alter?

Answer 9

Vmax

Question 10

What 2 clinical examples can this help?

Answer 10

Control of angiotensin production

Treatment of heart failure