Lecture 13

Question 1

Describe the graph for first order kinetics.

Answer 1

Natural log of substrate concentration over time one substrate goes to product

Question 2

Describe the graph for second order kinetics.

Answer 2

1/[s] over time two substrates being converted to product

Question 3

Describe zero order kinetics graph.

Answer 3

[s] over time it can be a unimolecular reaction meaning only changing shape not making or breaking bonds, enzyme is saturated or the reaction is uncatalyzed

Question 4

How do you find the reaction rate for a reversible reaction?

Answer 4

Rate of the forward reaction minus the rate of the reverse reaction

Question 5

Km?

Answer 5

[s] where rate is half maximum or where have of the active sites are full. Called the michaelis constant

Question 6

Vmax?

Answer 6

Maximum rate possible for given concentration of enzyme

Question 7

Kcat?

Answer 7

number of substrate molecules converted per active site per time called turnover number

Question 8

Ks?

Answer 8

dissociation constant for substrate binding

Question 9

Kcat/Km

Answer 9

Specificity constant, a measure of enzyme performance by predicting the fate of ExS. Will it fall apart to product or substrate.

Question 10

What are the assumptions made with the michaelis menten equation?

Answer 10

1. Assume that binding of substrate is at equilibrium- also know how much enzyme you add to reaction because you cant measure free enzyme.
2. Steady State Assumption [s]>>[E] formation of ES complex occurs at same rate as its loss.

Question 11

Describe reversible inhibitiors.

Answer 11

They use noncovalent interactions to bind. Competitive Noncompetitive Uncompetitive Non and Un are allosteric inhibitors

Question 12

What inhibition is this?

Answer 12

Competitive inhibition

• The Vmax, y intercept, is constant
• The Km is variable, x intercept
• The inhibitor and the substrate compete for the same active site, it can be overcome by adding more substrate

Question 13

What kind of inhibiton is this?

Answer 13

Noncompetitive Inhibition

• Vmax, Y intercept is variable
• Km, X intercept is constant
• The inhibitor can bind before or after substrate binds, doesn’t compete for same site, but once inhibitor binds it can’t overcome it and product won’t be produced

Question 14

What kind of inhibitor is this?

Answer 14

Uncompetitive

• Both Km and Vmax are variable
• The inhibitor binds after substrate and cannot create product

Question 15

What does a group specific irreversible inhibitor do?

Answer 15

Targets a specific amino acid. It has low specificity for its active site

Question 16

What does a substrate analog do?

Answer 16

Substrate mimic modifies enzyme and has high specificity for its active site

Question 17

What does a suicide inhibitor do?

Answer 17

Modifies substrate so it can’t form products and has very high specificity for its active site