Which form of Glycogen Phosphorylase is relatively inactive?
Phosphorylase A
Phosphorylase B
In phosphorylase B, where is the N terminus?
Floating free in the cytoplasm
Attached to the protein body
Unattached from protein
Which of the forms of glyocgen phosphorylase is most effected by cellular AMP/ATP levels?
Which of the following phosphorylates Glycogen Phosphorylase?
Phosphorylase B Kinase
Phosphorylase A Kinase
Phosphorylase Kinase
What protein causes the dephosphorylation of phosphorylase?
Protein phosphatase
Protein phosphorylase
Prokein Kinase P
What is needed for the reaction of Phosphorylase B --> A to reverse itself?
Water (and a lack of inhibiting AMP)
Water (and a lack of inhibiting ATP)
Water (and a lack of inhibiting GMP)
What is different about Phosphorylase A to B?
Ser14 has been phosphorylated
Tyr14 has been phosphorylated
Thr14 has been phosphorylated
What difference does phosphorylating Glycogen phosphorylase make?
Makes the relaxed form much more likely
Makes the taut form much more likely
Deactivates it entirely
How does phosphorylase B Kinase connect Glycogen Phosphorylase levels to the level of stimulation?
It is activated by Ca2+- when the muscle is stimulated, glucose is needed and so glycogen is broken down
It is deactivated by Ca2+- when the muscle is stimulated, glucose is not needed and so glycogen isn't broken down
What part of Phosphorylase B Kinase binds to Calcium?
Calmodulin
Calsequestrin
Troponin C
Which parts of phosphorylase B kinase are regulatory?
Alpha and beta
Alpha and gamma
Gamma and beta
Which part of phosphorylase B kinase is catalytic?
Gamma
Delta
Beta
In phosphorylase B kinase's Ca2+ binding sites, what are the affinities?
2 high 2 low
4 high
4 low
What protein causes the phosphorylation of Phosphorylase B Kinase?
cAMP dependent Protein Kinase
Adenylate Cyclase
Glycogen Phosphorylase
What is another name of cAMP dependent protein kinase?
Protein Kinase A
Protein Kinase B
Protein Kinase C
What is the role of inhibitor one?
To bind to protein phosphatase, activating it
To bind to protein phosphatase, inhibiting it
To bind to protein kinase A, activating it
What is contained in the N terminus domain of Glycogen Phosphorylase?
The catalytic site
The allosteric effector site
The regulatory subunit
How does glycogen get from it's binding domain to the catalytic site?
A hydrophobic tunnel
A hydrophillic tunnel
A lipophobic tunnel
Why is glycogen phosphorylase's site in a deep groove?
To prevent AMP from entering
To prevent ATP from entering
To prevent water from entering
What happens if water enters the active site?
Nothing
The enzyme is deactivated
Hydrolysis occurs instead of phosphorolysis
