Allosteric Enzymes

Question 1

Important amino acid side chains at the active site have to be either what for the reaction to occur

Answer 1

Protonated or deprotonated

Question 2

Extremophiles are what

Answer 2

Enzymes that work at extreme conditions

Question 3

Regulation can be what 4 things

Answer 3

Noncovalent modification, covalent modification, irreversible, reversible

Question 4

Example of noncovalent modification?

Answer 4

Inhibitors

Question 5

Example of covalent modification?

Answer 5

Phosphorylation

Question 6

Enzymes at the beginning of metabolic pathways are what and do not obey what rule

Answer 6

Are regulated and do not obey Michaelis-Menten kinetics

Question 7

Why do the enzymes at the beginning of metabolic pathways not obey the MM kinetics

Answer 7

They are usually multi-subunit enzymes with more than one active site and regulatory sites for binding of allosteric modulators.
Display cooperativity and sigmoidal kinetics.

Question 8

Allosteric enzymes display what type of kinetics

Answer 8

Sigmoidal

Question 9

ATP and CTP are what regulators?

Answer 9

ATP - Positive

CTP - Negative

Question 10

What enzyme stabilises the T state of hemoglobin?

Answer 10

CTP

Question 11

What is allosteric inhibition

Answer 11

binding an effector molecule at a site other than the protein’s active site

Question 12

What is hetero and homotropic allosteric regulation?

Answer 12

Homo - when allosteric modulator is a substrate for target enzyme. O2 for hemo
Hetero - allosteric modulator isnt enzymes susbstrate, H+ Co2 BPG

Question 13

Lowering the pH shifts the oxygen dissociation curve to hemoglob in what direction and why

Answer 13

To the right

lower affinity