Glycogen Flashcards
Where are alpha-1,4 linkages in glycogen found?
In the glycogen chains
Where are alpha-1,6 linkages in glycogen found?
At the branch points of glycogen
Why is glucose stored in the form of a branched molecule like glycogen?
Branches allow for more efficient degradation than if it were a single long chain
What enzyme is present in the liver that is not in the muscles and is important in glycogenolysis and gluconeogenesis?
Glucose-6-phosphatase
What is the main role of hepatic glycogen?
Used to generate glucose in times of hypoglycemia
What is the main role of muscle glycogen?
Used to generate ATP during exercise
What is the function of glycogen synthase?
Adds glucose units in an alpha-1,4-linkage.
What is the function of branching enzyme?
Adds glucose units in an alpha-1,6-linkage.
What are the enzymes of glycogen degradation?
Glycogen Phosphorylase and Debranching Enzyme
What are some of the secondary messenger systems for glycogen?
cAMP
PI
Calcium
What is the effect of the secondary messenger systems on glycogen?
Activates glycogen degradation and inhibits glycogen synthesis
What is the effect of Glucose-6-Phosphatase deficiency?
Increased glycogen in the liver and kidney that can lead to hypoglycemia and enlarged liver.
What is the effect of 1,4 alpha glucosidase deficiency?
Massive increase in glycogen in all organs and death before age 2 normally
What is the effect of glycogen debranching enzyme deficiency?
Increased glycogen in the muscle and liver but is mild
What is the effect of glycogen branching enzyme deficiency?
Normal amount of glycogen but they are found in long branches and cause liver cirrhosis that leads to death before age 2
