Enzymes

Question 1

What defines a good enzyme

Answer 1

• They lower delta G until it reaches substrate activation energy.
• Have a Kcat/ Km value that nears the diffusion controlled limit

Question 2

What is the diffusion control limit

Answer 2

The substrate activation energy

Question 3

What is a zeroth order reaction

Answer 3

v = k when the plateau is reached

Question 4

What is the first order reaction

Answer 4

v = k [S] (linear phase)

Question 5

What is the second order reaction

Answer 5

v = K[S]^2 (second substrate is required)

Question 6

Define the Haldane steady state assumption

Answer 6

concentration of [ES] remains the same throughout the enzymatic reaction

Question 7

what is the Michaelis-Menten equation

Answer 7

Vo = Vmax[S]/(Km+[S])

Question 8

What is an oxidoreductase

Answer 8

Transfers charge from one molecule to another

Question 9

What is a transferase?

Answer 9

Transfers a functional group from one molecule to another

Question 10

What is a hydrolase?

Answer 10

Adds water to a bond, creating one molecule with an additional H, another with an alcohol group

Question 11

What is a Lyase?

Answer 11

Breaks bonds by forming a double bond

Question 12

What is a Isomerase?

Answer 12

converts molecule to enantiomer

Question 13

What is a ligase?

Answer 13

Forms bonds between substances

Question 14

what are the three cofactors associated with enzymes

Answer 14

1. Ions
2. Co-enzymes
3. Prosthetic groups

Question 15

What is an apoenzyme

Answer 15

inactive enzyme lacking prosthetic group

Question 16

What is a haloenzyme

Answer 16

Active enzyme, prosthetic group is present

Question 17

List six ways that enzymes increase the reaction rate

Answer 17

1. Proximity effects
2. Acid-base catalysis
3. Metal - ion catalysis
4. Covalent catalysis
5. Electrostatic catalysis
6. Transition state stabilization

Question 18

Define proximity effect

Answer 18

Enzyme brings substrate closer to the catalytic site