Glycogen Synthesis and Glycogenolysis Regulation

Question 1

What are hte 3 types of biochemical control of glycogen synthesis and glycogenolysis?

Answer 1

• hormonal
• phosphorylative
• allosteric

Question 2

What does glycogen phosphorylase do?

Answer 2

• key enzyme in 1st step of glycogenolysis
• cleaves glycosidic bonds in linear portion of non-reducing ends of the glycogen molecule
• glucose ——– glycogen phosphorylase ——-> glucose-1-phosphate

glucogenolysis enzyme

Question 3

Glycogen phosphorylase acts repeatedly at the non-reducing ends of glycogen until it reaches a point (how many?) glucose residues away from a (α1→6) glycosidic branching point

Answer 3

4
The resulting glycogen structure is called a limit dextrin, because glycogen phosphorylase can no longer act to generate glucose-1-phosphate.

this is part of glycogenolysis

Question 4

Is glycogen phosphorylase active or inactive when it is phosphorylated?

Answer 4

GP_a-P = active
GP_b = inactive
glycogen phosphorylase is active when it is phosphorylated

glycogenolysis enzyme

Question 5

glycogen synthase

Answer 5

enzyme used once we have glycogenin + 8 + UPD-glucose to keep adding more glycogenin to the chain

Glycogen Synthesis