Chapter Six

Question 1

What is the biochemical function of proteolytic enzymes?

Answer 1

catalyzes proteolysis– the hydrolysis of a peptide bond

Question 2

Example of proteolytic enzymes—

1. low degree of substrate specificity
2. high degree of substrate specificity

Answer 2

1. papain

2. trypsin

Question 3

The specificity of an enzyme is due to the […] of the substrate of an enzyme. This precision is a result of […].

Rank the following proteolytic enzymes based on increasing substrate specificity:

Answer 3

precision interaction; intricate 3D structure of the enzyme protein

papain < trypsin < thrombin

Question 4

What are the six major classes of enzymes?

Answer 4

1. oxidoreductases
2. transferases
3. hydrolyases
4. lyases
5. isomerases
6. ligases

Question 5

Oxidoreductases: These enzymes […] between molecules. In other words, these enzymes catalyze […] reactions.

Ex: Lactate dehydrogenase– first pathway in […]

Answer 5

transfer electrons; oxidation-reduction reactions

glucose degradation

Question 6

Hydrolyases: These enzymes […] molecules by […].

Ex: […]

Answer 6

cleave; addition of H2O

trypsin

Question 7

Lyases: These enzymes add […] or […] to a […] or removes them to form […].

Ex: Fumarase is crucial to […].

Answer 7

atoms; functional groups; double bond; a double bonds

aerobic fuel metabolism

Question 8

Isomerases: These enzymes […] within a molecule.

Ex: […] in glycolysis

Answer 8

move functional groups

triose phosphate isomerase

Question 9

Ligase: Ligases […] molecules in a reaction powered by […].

Ex: […] important enzyme in DNA replication.

Answer 9

join two; ATP hydrolysis

DNA ligase

Question 10

The catalytic activity of many enzymes depends on the […] also known as […]. Without this, an enzyme is referred to as […]; the complete catalytically active enzyme is called […].

Answer 10

presence of small molecules; cofactors; apoenzyme; holoenzyme

Question 11

What are the two subdivisions of cofactors?

Answer 11

1. small organic molecules/coenzymes

2. metals

Question 12

Coenzymes are derived from […]. Tightly bound coenzymes are called […] groups. Loosely associated coenzymes are more like […].

Answer 12

vitamins; prosthetic (helper); cosubstrates

** cosubstrates because like substrates and products, they bind to the enzyme and are released from it **

Question 13

What is the formula for delta G?

Answer 13

delta G = (standard G) + RT ln([Products]/[Reactants])

Question 14

1 kJ = […] kcal

Answer 14

0.239

Question 15

Equation to determine standard delta G:

Answer 15

standard G = -RT ln([Products]/[Reactants])

Question 16

Equation to find K’eq:

Answer 16

K’eq = e^ (-standard G/2.47)

Question 17

Enzymes alter the […] but NOT the […].

Answer 17

reaction rate; reaction equilibrium

Question 18

Enzymes accelerate the […] but do not […] their positions that is a function only of the […].

Answer 18

equilibria; shift; free-energy difference

Question 19

Characteristics of the transition state:

Answer 19

1. least stable

2. highest free energy

Question 20

Free energy of activation:

Answer 20

difference in free energy between the transition state and the substrate

Question 21

The essence of catalysis is […] of the transition state.

Answer 21

stabilization

Question 22

Catalytic groups:

Answer 22

amino acids at the active site that directly participate in the making and breaking of bonds

Question 23

Binding energy:

Answer 23

free energy used to lower the activation energy due to the binding of [S] with enzyme

Question 24

What can inhibit the enzymes?

Answer 24

transition state analogs