L7

Question 1

Why does the oxidation reaction of sucrose not proceed despite being extremely thermodynamic favorable

Answer 1

Sucrose is unreactive without a catalyst.

Question 2

What are the 4 properties of acataly

Answer 2

1. Does not change the equilibrium of a chemical rxn, but ACCELERATES the RATE at which EQUILIBRIUM is achieved.
2. Functions by lowering the activation nrg of a chemical rxn.
   - Lower temp, lower pressure, lower conc, neutral pH etc…
3. Is not used up in the rxn.
4. Even when a catalysts forms an intermediate compounds during the reactants the catalyst is regenerated.

Question 3

Write eqn of generic catalyst

Answer 3

A + B + C -> ABC -> AB + C

Question 4

How do enzymes differ from chemical catalysts?

Answer 4

• Have all the same properties as chemical catalysts.
• With added specificity
  a) complementarity in: stereochemistry, electrostatics, H-bonds, and shape

Question 5

Enzymes are remarkable catalysts, enhancing reaction rates by up to ____ fold!

Answer 5

10^17

Question 6

What is “a”

Answer 6

The ratio of the value of kcat for the enzymatic rxn and the value of k^uncat of the corresponding uncatalyzed reaction in aqueous sln under the same conditions.

Question 7

How to determine if co-factor or co-enzyme or prosthetic group?

Answer 7

N/A

Question 8

Examples of prosthetic group?

Answer 8

1. FMN
2. FAD
3. Heme
4. MoCo

Question 9

Example of coenzymes?

Answer 9

Organics, bound loosely e.g.

Question 10

Example of cofactors?

Answer 10

Fe / Zn ions

Question 11

Example of cosubstrate?

Answer 11

NAD+

ATP

Question 12

Example of inorganic factors?

Answer 12

Zn2+

Fe-S cluster

Question 13

Define Apoenzyme

Answer 13

enzyme with cofactor

Question 14

What is the enzyme commission #

Answer 14

N/A

Question 15

Example:

EC 3.4.21.89

Answer 15

3 = hydrolase
4 = acting on a peptide bond
21 = uses a serine nucleophile
89 = specific protease

Question 16

What are the 6 classes of enzymes in order of their classes

Answer 16

1. Oxidoreductases aka dehydrogenase
2. Transferases
3. Hydrolases
4. Hydratase
5. Isomerase
6. Ligase

Question 17

1. Draw a dehydroganese/oxidoreductase rxn.
2. What does it transfer?
3. What does it usually use as cofactors?

Answer 17

1. ethanol + NAD+

- –>NAD:alcohol / dehydrogenase

Question 18

1. Draw a transferase rxn.

2. What does it transfer?

Answer 18

1. Glucose + ATP

- ———> ATP:glucose/ phosphotransferrase

Question 19

1. Draw a hydrolases rxn.

2. Example?

Answer 19

1. glucose-6-phosphate + H2O

- ———–> glucose-6- phosphatase

Question 20

1. Draw a hydrotases rxn.

2. Another name for hydratases?

Answer 20

1. cis-aconitate + H2O

- ————-> aconitate hydratase

Question 21

1. Draw a isomerase rxn.

Answer 21

Glc-6P

————–> glc-6-phosphatase isomerase

Question 22

1. Draw a ligase rxn.

Answer 22

Pyruvate + Bicarbonate + ATP

———> pyruvate carboxylase