Glycogenolysis Flashcards
What does epinephrine/glucagon do to glycogenolysis?
Stimulate it.
When does Glycogenolysis occur?
Between meals to release glucose to maintain blood glucose levels.
What is the main cleaving enzyme involved in glycogenolysis?
Glycogen phosphorylase.
What does glycogen phosphorylase do?
It cleaves Glucose off non-reducing ends. ALPHA 1-4.
What happens to the cleaved glucose?
Glucose –> G-1-P
What happens to G-1-P?
G-1-P –> G-6-P (Phosphoglucomutase)
What happens to G-6-P?
The G-6-P can enter the glycolytic pathway and be used for energy, or it can be converted into glucose and transported. (G-6-Phosphotase)
Why G-6-P –> Glucose?
Because glucose can cross membranes and leave liver cells where G-1/6-P cannot.
What point does the glycogen phosphorylase cleave glucose molecules off?
Until there are 4 glucose molecules to the branch point.
What happens at branch point?
De-branching enzyme cleaves off 3 glucoses from the last 4 and attaches it onto another non-reducing end.
What happens to the last glucose left?
The glucose is cleaved off, becoming G-1-P.
What enzyme cleaves off the last glucose?
Glucosidase.
What linkage does Glycogen phosphorylase break?
ALPHA 1-4
What linkage does Glucosidase break off?
ALPHA 1-6
When is Glycogen Phosphorylase more active?
When phosphorylated.
