Metabolic Regulation And Control

Front 1

Give 3 different examples of enzyme regulating mechanisms

Back 1

Allosteric Regulation, Product Inhibition and Isozyme Expression

Front 2

What is Allosteric Regulation?

Back 2

It is conformational changes induced or stabalised by allosteric effectors which alter enzyme activty

Front 3

Allosteric inhibitors modify the active site of the enzymes so that substrate binding is ??

Back 3

Reduced and Prevented

Front 4

What do allosteric activators do?

Back 4

They modify active site of the enzyme so that the affinity for the substrate is increased

Front 5

AMP-activated kinase is a 'master' regulator' of fat metabolism. True or False?

Back 5

False. It is a master regulator of energy metabolism

Front 6

AMPK is an example of what type of allosteric effector?

Back 6

Allosteric Activator. It is activated by AMP

Front 7

Give an example of allosteric inhibition

Back 7

Phosphofructokinase (PFK)

Front 8

PFK is inhibited by high [ATP] i.e. at a high energy charge. True or False?

Back 8

True

Front 9

Give an example of Product Inhibition

Back 9

Hexokinase

Front 10

Hexokinase is inhibited by glucose-6-phosphate. True or False

Back 10

True

Front 11

Hexokinase isozymes dont have different kinetic properties. True or False?

Back 11

False. They do have different kinetic properties

Front 12

What is the minimal metabolic system?

Back 12

Two enzymes that communicate via a single intermediate

Front 13

Control by enzymes over a global steady state. Global steady state is quantified by _________________ __________________.

Back 13

Control coefficients

Front 14

What are the control coefficients?

Back 14

Metabolite control (X) and Pathway flux (J)

Front 15

Control by metabolites over _______________ _________________ ___________________________

Back 15

Local system properties

Front 16

Local steady state is quantifies by ??

Back 16

Elasticity coefficients

Front 17

Control by effectors over ___________ _________________ ________________________

Back 17

Any system property

Front 18

System sensitivity to effectors is quantified by regulation coefficient. True or False?

Back 18

False. Quantified by response coefficients

Front 19

What are the 'main laws' of Metabolic Control Analysis?

Back 19

Summation and Connectivity Theorems

Front 20

Control over metabolic flux resides in a single step. True or False?

Back 20

False. Control over metabolic flux does not reside in a single step but is generally shared between all enzymes in a system

Front 21

Which enzymes should be manipulated to optimise metabolic fluxes to yield desirable products?

Back 21

Flux Control

Front 22

Where should therapeutic drugs be targeted to maintain or restore homeostasis?

Back 22

Concentration control

Front 23

Negative Feedback ______________________metabolic systems and Positive feedback _____________________ metabolic systems

Back 23

inhibits
reinforces

Front 24

Stable flux or (dampened oscillations) are associated with _________________ feedback while turbo design (explosion or block) is associated with _______________________ feed back

Back 24

Negative
Positive

Front 25

Positive feed-forward _______________________ metabolic systems and is associated with __________________ _____________________

Back 25

Activates
Spike Filter

Front 26

Glucokinase kinetics allow ________________ ___________________

Back 26

Glucose sensing

Front 27

State the differences in substate affinity, dependency and product inhibition between hexokinase and glucokinase

Back 27

Substrate affinity:
Hexokinase Km=0.1mM Glucokinase K0.5=5mM
Substrate dependency:
Hexokinase= Saturating Glucokinase= Cooperative
Product Inhibition:
Hexokinase= Yes Glucokinase= No

Front 28

Specific isozyme expression regulates ____________________ reaction and thus influences control of ________________________ _________________________

Back 28

Hexokinase
Energy Metabolism

Front 29

Describe glucokinase kinetics in the pancreatic B cell

Back 29

Blood glucose >5mM , glucose catabolism increases, ATP/ADP increases and insulin release increases

Front 30

Descibe hexokinase kinetics in the muscle cell

Back 30

Muscle contraction, ATP/ADP decreases, glucose catabolism increases, ATP/ADP increases