Ch. 12 Carbohydrate Pathways Flashcards
What types of linkages make up the structure of glycogen?
Alpha-1,4 and alpha-1,6
What effect does glycogen branching have on solubility?
Glycogen branching increases solubility
What effect does glycogen branching have on the rate of synthesis and breakdown?
Glycogen branching increases the rate of both processes
What 3 enzymes are key to glycogen synthesis (HINT: PUG)?
- Phosphoglucomutase
- UDP glucose synthase
- Glycogen synthase
When does the branching step of glycogen synthesis occur?
After 11 glucosyl units have been added to the glycogen core
What is glycogenin?
The core and primer for glycogen formation
What is the glycogen branching enzyme called?
Glycosyltransferase
How many glucosyl units from the nonreducing end do you count before breaking the alpha-1,4 linkage to form the alpha-1,6 linkage in glycogen synthesis?
About 6-7 units
What is the primary enzyme that works through glycogenolysis?
Glycogen phosphorylase
What does glycogen phosphorylase do?
Breaks alpha-1,4 links
When/where does glycogen phosphorylase stop breaking alpha-1,4 links?
4 glucosyl units/residues away from the branching point
What linkage can glycogen phosphorylase not break?
Alpha-1,6 links
What are the products for glycogenolysis?
Glucose-1-phosphate and glucose
What does the transferase activity of the debranching enzyme do 4 units away from from alpha-1,6 link?
It transfers 3 of those units to the nonreducing end of the chain
What does the glucosidase activity of the debranching enzyme do for the remaining glucosyl unit that has the alpha-1,6 link?
Breaks off the remaining unit to form a free glucose
