Glycogen Flashcards
Basic function of glycogen
Storage for of glucose
Where is abundant
Muscle and liver
How does muscle use glycogen
For itself as energy!
Prolonged exercises
How does the liver use glycogen
For others, to maintain blood glucose when needed
During fasting
1, 4 linkage is ____
Straight
1,6 linkage is ____
Branching
Branching of glycogen
Makes it more soluble
Store more glycogen
increases rate of glycogen synthesis and breakdown
Glycogen synthesis can be done from
Preexiting glycogen molecule
Or
Glycogenin center
_____ forms a glycosidic bond via _____ to a glucose ______ end via autoGlycosylation
Glycogenin
Tyrosine
Reducing
From G6P what can happen
Glycolysis
Or
Made to Glucose
Or
PPP
Muscles do not have ____ so what is inevitable
No glucose 6 phosphatase
Which means G6P cannot go back to glucose, it must go to glycolysis
____ is a high energy form of glucose
UDP glucose
Very reactive
Glycogen synthase makes what kind of links
1,4
Branching enzyme is aka and makes what links
4:6 transferase
1,6 links
What is elevated in fasting or fight or flight
Glucagon
Epinephrine
Glucagon and epinephrine favor
Glycogen to glucose
Insulin favors
Glucose to glycogen
What happens when glycogen phosphorylase gets phosphorylated
It turns more glycogen to glucose
What do glucagon and epinephrine want to happen
Want glyc. Phosphorylase to get phosphorylated so it turns on and revs up the gly to glucose production
What happens when glycogen synthase gets phosphorylated
It’s activity stops so it stops making glycogen
Insulin wants ___ of glyc phosphorylase and glycogen synthase
Dephosphorylation
What does Dephosphorylation of glycogen synthase do
Makes it more active. Make it want make more glycogen
What does Dephosphorylation do to glycogen phosphorylase
Lowers activity so it will stop turning glycogen to glucose
What does calcium/calmodulin do
Immediately breaks down glycogen by
Activate GPkinase A which phosphorylates glycogen phosphorylase
Which leads to glycogen break down
Defective breakdown of glycogen in liver vs muscle
L= hypoglycemia
M = weakness
Glycogen storage disease type 1 aka
Which enzyme
Von Gierke’s disease
G6phosphatase deficiency
Von gierkes enzyme does what normally
In the liver only and it turns G6P to glucose
Logically describe von gierke’s
When the G6phosphatase no longer works, that means you cannot turn G6P to glucose
Which means you cannot have glucose in the blood
So you’ll be tired and you’ll have more lactic acid and excess glycogen (which means a large liver)
SEE pic slide 52
With von gierkes who will be ok
Muscles
It’s a liver enzyme
Type 2 aka and enzyme
Pompe
Lysosomal α1,4 glucosidase
If you spell it like the volcano
POMPEII
It has a 2 at the end
What happens to glycogen in type 2 deficiency
It accumulates in lysosomes
Clinical features of pompe disease
Cardiomegaly, muscle weakness, death by 2 yrs old
Pompe wont have
Hypoglycemia in liver
Enlarged tongue, hypotonia, no metabolic problems
Pompe disease
Cori’s disease is type
III
Type III is a disease of
The debranching enzyme
Can’t break 1,6 to 1,4
Mild hypoglycemia in Cori’s disease because
Liver can still make glucose cuz glucose 6 phosphatase is still intact
Cori’s enzyme effects ___ mainly
Muscles
Cori’s disease key point
Gluconeogenesis is intact
Which disease has a HUGE round Santa belly
Type I
Von gierke’s vs Cori
Muscle involvement apart of Cori’s
Weak muscles
Type V disease aka
McArdle’s disease
McDonald’s 5 dollar meal
McArdles deficient enzyme is
MUSCLE glycogen phosphorylase
Symptoms of McArdles
Muscle cramps, weakness on exercise, myoglobinuria , dark pee after exercise
type VI glycogen disease aka and enzyme
Hers
HEPATIC Glycogen phosphorylase
Glycogen diseases are _____
Inherited genetic disorders
If liver is affected, _____ is common with hepatomegaly
Hypoglycemia
