Unit II Glycogenolysis Flashcards
What is the storage form of glucose?
glycogen
What are the primary sites of glycogen storage?
liver and skeletal muscle
What type of glycosidic bond is formed in chains of glucose?
alpha(1-4)
What type of glycosidic bonds are formed in branches of glucose?
alpha(1-6)
Where in the cell is glycogen stored?
the cytosol
What enzyme breaks alpha(1-4) bonds?
glycogen phosphorylase
What is the coenzyme with glycogen phosphorylase?
pyridoxal phosphate
What is the product of glycogen phosphorylase breaking the alpha(1-4) bond?
glucose-1-phosphate
What enzyme converts glucose-1-phosphate to glucose-6-phosphate?
phosphoglucomutase
Once a glucose branch has been broken down to its last four molecule, what enzyme removes the outer three molecules?
glucosyl-(4:4)-transferase
What enzyme removes the last glucose in a branch?
Amylo-alpha-(1,6)-glucosidase
What is the key regulatory enzyme of glycogenolysis?
glycogen phosphorylase
What hormones are involved in the regulation of glycogen breakdown?
glucagon, epinephrine, and norepinephrine
What are the allosteric regulators of glycogenolysis?
AMP and calcium
On what tissue would glucagon have an effect?
the liver
On what tissue(s) would norepinephrine and epinephrine have an effect?
muscle and liver
What is adenylyl cyclase activated by in glycogen breakdown?
glucagon, epinephrine, and norepinephrine
Once adenylyl cyclase is activated, what does it produce?
cAMP
What powerful enzyme is stimulated by the presnece of cAMP?
protein kinase A (AMPkinase)
In general, what does AMPK inhibit?
synthesis pathways
In general, what does AMPK stimulate?
breakdown pathways
What is the inactive form of glycogen phosphorylase?
glycogen phosphorlyase “b”
What would activate glycogen phosphorylase “a”?
the presence of AMP
What would inhibit glycogen breakdown?
ATP attaching to glycogen phosphorylase “a”
What is a subunit of glycogen phosphorylase kinase complex?
calmodulin
What would activate calmodulin?
the attachment of calcium
The activation of glycogen phosphorylase kinase stimulates what?
the breakdown of glycogen (glycogen phosphorylase a)
