1.12-Glycogen Metabolism Flashcards
Where are the two main storage places for Glycogen?
The liver and skeletal muscle
How many reducing ends are there in Glycogen? Which number do we give to this carbon?
1 Reducing end. Carbon 1
How many non reducing ends are there in Glycogen?
FREAKING TONS
What are the straight chain linkages in Glycogen? What are the branch links?
Chain: 1,4 alpha Branches: 1,6 alpha
Which end do we use to start breaking down glycogen?
The terminal end…the NONreducing end
What is the enzyme that helps us break down glycogen?
Glycogen Phosphorylase
Is the breakdown of glycogen hydrolysis or phosphorolysis?
Phosphorolysis
After how many glucose molecules does glycogen phosphorylase cut?
Every 4th glucose molecule
What is the enzyme that breaks the alpha 1,6 linkages? if you get this wrong I will hurt you..
Debranching Enzyme
What does phosphorglucomutase do after a branch has been cut AND to start Glycogen synthesis?
Since we had a Glucose 1 Phosphate we need it changed to Glucose 6 phosphate for Glycolysis….REVERSE to start Glycogen Synthesis!!
Is the substrate for glycogen synthesis sugar? What is the name of the substrate?
NO! its a sugar-nucleotide!! UDP-Glucose
What catalyzes UDP to come off the glucose to synthesize the glycogen chain? THESE ENZYMES HAVE STRAIGHT FORWARD NAMES :)
Glycogen Synthase
What enzyme is needed to make a 1,6 alpha linkage (a branch)?
Glycosyl (4-6) Transferase…It transfers the chunk of glucose molecules from a 4 linkage to a 6 linkage :)
What is the name of the primer needed for Glycogen synthesis?
Glycogenin
What is the only enzyme that both glycogeneis and glycogenolysis have in common?
Phospho-Gluco-Mutase
How are the pathways of Glycogenesis and glycogenolysis related concerning their regulation?
They are reciprocally regulated. When one is going it inhibits the other.
What are the two forms of Glycogen Phosphorylase? Which form is active? Which form is inactive?
A=active and B=inactive
Here’s the Sitch: Your working out and you need more glucose. What two things does protein kinase A phosphorylate and what is the result of each?
Protein Kinase A phosphorylates: 1. Phosphorylase Kinase which activates phosphorylase to break glycogen. 2. Glycogen Synthase which inactivates it
What does phosphorylation of BOTH enzymes in building/breaking down of glycogen result in?
Glycogen Degradation
What does Dephosphorylation of both enzymes in breaking/building glycogen result in?
Glycogen Synthesis
What is even faster then hormonal control for glycogen regulation?
Allosteric Regulation by AMP and Glucose
What is the R state? T State?
R=Ready(Active) T=Tired (Less Active)
What is the default state for phosphorylase in the MUSCLE? a or b? What is it activated by?
B (less active in muscle) Activated to R by AMP
What is the default state for Phosphorylase in the LIVER? a or b? What is it deactivated by?
A Deactivated by glucose to T
