Lecture 10 - Enzyme Mechanisms Flashcards Preview

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Flashcards in Lecture 10 - Enzyme Mechanisms Deck (24):
0

Why are enzymes central to all biochemical processes?

Enzymes show greater substrate specificity, and have an optimal arrangement of catalytic groups for chemical reaction

Enzymes increased reaction rates but not reaction equilibria

1

Which enzyme catalyzes the polymerization of nucleotides to form DNA?

DNA polymerase

2

List the inorganic ions that serve as cofactors for enzymes

Cu2+
Fe2+ or Fe3+
K+
Mg2+
Mn2+
Mo
Ni2+
Zn2+

3

Interaction between substrate and enzyme is mediated by what?

The same noncovalent forces that stabilize protein structure

4

Lowers energy of transition state making it easier to form

Transition state stabilization

5

Arranges atoms for optimal activity

Orientation

6

Binding removes interactions with solvent (water)

Desolvation

7

Substrate binding changes conformation of enzyme

Induced fit

8

What kind of catalysis pushes or pulls a proton?

Acid – base catalysis

9

What kind of catalysis adducts or intermediates?

Covalent catalysis

10

What kind of catalysis involves Lewis acid and redox agents?

Metal ion catalysis

11

Energy derived from ES interaction is called what?

Binding energy (ΔGB)

12

True or false? Enzymes use binding energy to achieve substrate specificity and to stabilize the transition states through noncovalent interactions.

True

13

What kind of bonds or interactions are considered non-covalent interactions?

Hydrogen bonds
Ionic interactions
Hydrophobic interactions

14

True or false? The mechanism of enzyme binding is a "lock and key" mechanism.

False, it is NOT

15

True or false? Enzymes bind the transition state with a greater affinity than either substrates or products.

True

16

Transition state analogues are good ________ of enzymes

Inhibitors

17

Class of enzymes involved in transferring electrons

Oxidoreductases

18

Class of enzymes involved in the group transfer reactions

Transferases

19

Class of enzymes involved in hydrolysis reactions

Hydrolases

20

Class of enzymes involved in the addition of groups to double bonds or double bond formation by removing groups

Lyases

21

Class of enzymes involved in transfer of groups within a molecule to give an isomer

Isomerases

22

Class of enzymes involved in the formation of C – C, C – S, C – O, and C – N bonds by condensation reactions coupled with ATP cleavage or similar cofactor

Ligases

23

What's the relationship between activation energy and rate?

The relationship is inverse and exponential. As activation energy decreases, the rate increases.