Enzyme Mechanisms

Question 1

What are the different types of enzyme mechanisms

Answer 1

Question 2

What are Lewis acids and bases

Answer 2

Question 3

What is general acid catalysis

Answer 3

Question 4

What is general base catalysis

Answer 4

Question 5

What is specific acid catalysis

Answer 5

Question 6

What is specific base catalysis

Answer 6

Question 7

What is Concerted General Acid-Base catalysis

Answer 7

Question 8

What is the transition state for the uncatalysed keto-enol tautomerisation

Answer 8

Question 9

What is an election sink

Answer 9

Question 10

What are the formal charges when the nucleophile and electrophile start off neutral

Answer 10

Question 11

What are the formal charges when the electrophile is positive and nucleophile is negative at the start of the reaction

Answer 11

Question 12

What is the mechanism for Acid-catalysed keto-enol tautomerisation

Answer 12

Question 13

What is the mechanism for Base-catalysed keto-enol tautomerisation

Answer 13

Question 14

What is the mechanism for Concerted mechanism of acid/base-catalysed keto-enol tautomerisation

Answer 14

Question 15

What is the effect of pH on enzyme activity and why (including the interpretation of a bell shaped ph profile

Answer 15

Question 16

How can pKa values be shifted by the microenvironment in the active site of an enzyme

Answer 16

Question 17

How can pKa be decreased when a positive charge is near a negative charge in the active site of an enzyme

Answer 17

Question 18

What is covalent catalysis

Answer 18

Question 19

What is a group transfer reaction

Answer 19

Covalent catalysis is important for these

Question 20

How can a group transfer reaction occur via a ternary complex

Answer 20

(a type of covalent catalysis mechanism)

Question 21

Have can a group transfer reaction occur via a ping pong mechanism

Answer 21

(A type of covalent catalysis mechanism )

Question 22

How is covalent catalysis important for making the substrate more reactive in a single substrate reaction

Answer 22

Question 23

How can formation of a schiff base be used to activate carbonyl groups

Answer 23

Question 24

Give the uncatalysed and catalysed mechanism for acetoacetate decarboxylase (activation of a carbonyl carbon)

Answer 24

Question 25

What is chemical trapping of enzyme intermediates and what is it used for

Answer 25

Question 26

What is electrostatic catalysis

Answer 26

Electrostatic catalysis occurs when the enzyme active site stabilizes the transition state of the reaction by forming electrostatic interactions with the substrate. The electrostatic interactions can be ionic, ionic-dipole, dipole-dipole, or hydrophobic interactions.

Question 27

What are the two classes of metal con requiring enzymes

Answer 27

Question 28

What are metal ions involved in

Answer 28

Question 29

Give some examples of redox roles of iron and manganese

Answer 29

Question 30

How can water be activated

Answer 30

Question 31

What is catalysis through orientation and proximity effect

Answer 31

Question 32

What is the difference between an uncatalysed and enzyme catalysed reaction with reference to orientation and proximity effects

Answer 32

Question 33

What is preferential binding of the transition state

Answer 33

Question 34

Why are uncatalysed reactions slow

Answer 34

Question 35

What does a high and low pka mean

Answer 35

High ~ weak acid as Ka is smaller Low - strong acid Ka tells you how completely an acid dissociates in aq solution