Flashcards in 1.12 Glycogen Metabolism Deck (22)
Where is Glycogen mostly stored
In liver and muscle
Glycogen is degraded by removal of a terminal glucose from where?
the nonreducing end of a glycogen chain
What enzyme degrades the terminal glucose from the glycogen chain
Glycogen metabolism is demonstrative of a hydrolysis or a phosphorolysis?
At what point on the Glycogen chain does the enzyme stop removing terminal glucose molecules?
On the fourth residue from the branch point
After Glucose molecule is released from Glycogen chain, what structure is it?
What enzyme converts Glucose 1-phosphate to Glucose 6-phosphate?
What activates and prepares Glucose 1-phosphate to be added to the glycogen chain?
The activation and attachment of a sugar nucleotide
Ex: G1P + UTP --> UDP-Glucose
What enzyme catalyzes the addition of a sugar nucleotide to G1P
What enzyme catalyzes the first step of glycogen synthese by converting G6P to G1P
What enzyme catalyzes the addition of the glycosyl unit to the glycogen chain?
What happens to UDP during the addition of the glycosyl unit to the terminal end of the glycogen chain
It is displaced by the terminal Hydroxyl group of the growing glycogen molecule
T or F, The glycosyl residues can only be added to the glycogen chain if it already contains 4 residues
How is a branch made during Glycogen synthesis
Breaking of an alpha 1-4 link of a block of about six or seven glycosyl residues from the terminal nonreducing end. This block is transfered to a more interior residue on the C-6
What enzyme catalyzes the alpha 1-6 linkages found at branching sites
branching enzyme Glycosyl (4-6) transferase
Role of Glycogenin
Acts as a primer for new branches of glycogen. Since glycogen synthase can only add to chains of 4 residues, this enzyme makes those first four residues attach so that glycogen synthase can act
What is the only enzyme that is common to both glycogen synthesis and metabolism
T or F, Glycogen synthesis and breakdown are reciprocally regulated, stimulation of one inhibits the other
Glycogen Phosphorylase is phosphorylated to form a, what occurs?
This is the active form of glycogen phosphorylase and triggers glycogen breakdown
Phosphorylase a is dephosphorylated or phosphorylated?
Glycogen Synthase a is dephosphorylated or phosphorylated?