1. Lecture 14 Slides rh

2. Glycogen: the glucose buffer…

3. Glycogen granules
~ 1600 glucose monomers per granule

4. fig 7-14

5. Glycogen in real life…

6. How is glycogen synthesized?
-sequential addition of glucose to a
growing a1-4 linked linear polymer
glycogenin, then glycogen synthase
-creation of branches composed of a1-6
linkages
branching enzyme

7. Glucose ends… O 1 2 3 4 5 6
non-
reducing
end
reducing
end

8. polymer ends…
fig 7-14

9. pg 597

10. addition of UDP carrier to glucose-1-P
fig 15-29

11. addition of glucose monomers to the growing glycogen chain
fig 15-30

12. Glycogen branching enzyme creates branches
fig 15-31

13. Glycogen branching enzyme creates branches10
a1 4 3 7
a1 6
fig 15-9

14. How is glycogen broken down?
-sequential removal of glucose-1P from
the non-reducing end
glycogen phosphorylase
-dismantling of those pesky branches
debranching enzyme

15. fig 14-11

16. debranching
enzyme
removes
branches
fig 15-26

17. 7 4 7 1 Debranching enzyme removes branches a1 4 a1 6 a1 4 a1 4 a1 6
free
glucose 4
a1 6
a1 4 7
a1 4 1
a1 6
transferase
activity
a1-6
glucosidase

18. Allosteric control of glycogen phosphorylase
fig 15-36

19. Hormonal control of glycogen phosphorylase
fig 15-34

20. regulation of
glycogen
synthase
by phos-
phorylation
as well…
fig 15-37

21. Liver glucose
metabolism
fig 23-13

22. Blood glucose
level is critical
and stringently
regulated
fig 23-23

23. The
Cori
cycle
fig 23-20

24. Liver as a "glucostat"
low blood
glucose
high blood
glucose

25. Glucagon: the hormone of starvation
phosphorylation
of enzymes
alteration of
fructose 2,6 bis P

26. Insulin: the hormone of plenty

28. fig 23-24

29. b cell glucose sensing: an ATP gated channel