Enzyme Structure and Function

Question 1

induced fit model of enzyme binding

Answer 1

substrate alters the enzyme active site (hand shake changes the other person’s hand)

Question 2

4 catalytic strategies

Answer 2

1. acid/base
2. covalent
3. electrostatic
4. proximity/orientation

Question 3

1. [catalytic strategy] acid/base catalysis*

Answer 3

n/a

Question 4

2. [catalytic strategy] covalent catalysis*

Answer 4

enzymes form a covalent bond with the target molecule

electron carrier - decarboxylation (removes carboxyl group)

Question 5

3. [catalytic strategy] electrostatic catalysis

Answer 5

DNA is negatively charged with phosphate groups, magnesium 2+ can stabilize the negative charge (used by DNA pol)

Question 6

4. [catalytic strategy] proximity/orientation effects*

Answer 6

?

the crashing effect is increased; orientation also matters

Question 7

kinase*

Answer 7

adds phosphate functional groups to different substrates

Question 8

peptidyl transferase

Answer 8

transferring an amino acid to a chain of amino acids using tRNA (see picture)

Question 9

1. ligase

Answer 9

one of six types of enzymes

• joins two DNA fragments together

Question 10

3. oxidoreductase

Answer 10

catalyzes forward/reverse directions by moving electrons between molecules

ex. lactate dehydrogenase is able to remove a hydrogen from lactic acid (see picture)

Question 11

4. isomerase

Answer 11

changes one isomer into a different isomer (ex. phosphoglucose isomerase, chances glucose-6-P to fructose-G-P)

Question 12

5. hydrolase

Answer 12

uses water to cleave a molecule

ex. Protease (cuts Lys-Ala into two)

Question 13

6. lyase

Answer 13

cleaves a molecule without water or oxidation

Question 14

6 types of enzymes

Answer 14

1. ligase - joins two molecules
2. oxidoreductate - moves electrons
3. transferase - transfers one functional group to another
4. isomerase
5. hydrolase
6. lyase

LOT-IHL

Question 15

3. transferase

Answer 15

transfers one functional group to another

Question 16

co-enzyme

Answer 16

organic carrier molecules

• makes catalysis run more smoothly
• NADH (electron carrier)
• NADH acts as an electron-carrying co-enzyme

Question 17

co-factor

Answer 17

stabilizes the charge of DNA

• more directly involved in actual catalysis