BoC Enzymes

Question 1

What are 6 main types?

Answer 1

oxoreductases, transferases, hydrolases, lyases, iosomerase, ligase

Question 2

Draw out enzyme reaction scheme

Answer 2

see notes

Question 3

What is kd

Answer 3

k2/k1

Question 4

What is km?

Answer 4

(k2+k3)/k1

Question 5

k3 also known as

Answer 5

kcat

Question 6

What 2 monosaccharides do bacterial cell walls contain?

Answer 6

N-acetylglucosamine and N-acetyl muramic acid

Question 7

Draw bacterial cell wall

Answer 7

see notes

Question 8

Lysozyme binds…

Answer 8

the sugar moiety of the peptidoglycan layer, has a hydrophobic active site cleft

Question 9

Draw lysozyme action basic

Answer 9

see notes

Question 10

This mechanism illustrates principles of…

Answer 10

Geometric effects, nucleophilic attack, acid catalysis

Question 11

What is an example of an irreversible inhibitor?

Answer 11

Nerve agent sarin, interacts with acetylcholinesterase

Question 12

What is a suicide inhibitor and what is an example of one?

Answer 12

Enzyme starts to catalyse reaction of inhibitor, forms covalent bond, can’t proceed further, stuck with inhibitor eg. penicillin for glycopeptide transferase

Question 13

What is an eg of a competitive inhibitor?

Answer 13

Methotrexate, a chemo drug that mimics folic acid, competes with folic acid for thymine synthesis, folic acid essential for DNA synthesis

Question 14

How can enzymes be controlled

Answer 14

(de)phosphorylation, negative feedback (often genetic control with TF), Activation of zymogens (inactive enzymes that can be switched on but not off unless destroyed), allosteric binding, compartmentalisation

Question 15

Describe how haemoglobin is cooperative (draw diagram of the concerted and sequential model)

Answer 15

see notes

Question 16

Which 2 lysozyme amino acids participate in stabilising the transition state?

Answer 16

Glutamic acid and aspartic acid lie either side of bond between D and E in active site
glutamic acid in non-polar enviroment, largely protonated and acts as base
Asp in polar environment, deprotonated and negativey charged
Once substrate bound glu donates H to O of glycosidic bond