Enzyme Facts

Question 1

Enzymes function by:

Answer 1

What: Lowering the activation energy of reactions
Why: For formation of transition states

Question 2

What do enzymes serve as?

Answer 2

Templates that increase local substrate concentration

Question 3

What do enzymes provide?

Answer 3

What: AA residues
In which: R group performs specific roles in catalysis

Question 4

All enzymes are proteins except:

Answer 4

Ribozymes

Question 5

What do enzymes catalyze

Answer 5

Specific reaction or reaction type

Question 6

What do enzymes exhibit?

Answer 6

Optical specificity

Question 7

Are enzymes used up in the reaction?

Answer 7

• No
• Enzyme + Substrate -> Enzyme/Substrate complex -> Enzyme (regenerated) + Product

Question 8

Do enzymes alter the equilibrium constants?

Answer 8

No

Question 9

Do enzymes change the free energy for the reaction?

Answer 9

No

Question 10

Reactions with a -ΔG and spontaneously occur

Answer 10

Exergonic reactions

Question 11

Reactions with a +ΔG and require energy input to occur

Answer 11

Endergonic reaction

Question 12

Factors that affect enzymes

Answer 12

• Temperature
• pH
• Enzyme concentration
• Substrate concentration
• Inhibitors

Question 13

When temperature increases the rate of reactions _____

Answer 13

Increase

Question 14

At temperatures greater than 102F what happens to the proteins?

Answer 14

Denature

Question 15

At temperatures greater than _____ proteins denature

Answer 15

102F

Question 16

At temperatures below 98F what happens to reaction rates?

Answer 16

Slow down

Question 17

Pepsin pH

Answer 17

Acid 1.5-2.0

Question 18

Carbonic anhydrase in RBCs pH

Answer 18

Neutral 7.3-7.4

Question 19

Trypsin in the small intestines pH

Answer 19

Basic 8.0-9.0

Question 20

Describes the effects of substrate concentration on activity of many enzymes

Answer 20

Michaelis-Menten Curve
E+S->ES->E+P

Question 21

Maximum velocity of reaction

Answer 21

Vmax

Question 22

The concentration of the substrate at which the reaction occurs at the _____

Answer 22

Rate of 1/2 Vmax

Question 23

List 2 experimental methods that determines Vmax and Km

Answer 23

• Lineweaver-Burke Plot
• Eadie-Hofstee

Question 24

What is the disadvantage of Lineweaver-Burke Plot?

Answer 24

Small experimental error can result in large error in the graphically determined values

Question 25

What is the advantage of the Eadie- Hofstee Plot?

Answer 25

Single reciprocal plot

Question 26

How do I determine Km in Eadie-Hofstee Plot?

Answer 26

Slope = -Km