07 Glycogen
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- muscles cannot release glucose from glycogen
- 1-4 linear linkage
- 1-6 branching
- branching makes it more soluble and better storage
- lysosomes can collect glycogen and break it down to glucose
- glycogen phosphorylase shrink purple link down to 3 or so
- debranching enzyme moves purple to red, releasing one molecule of glucose (green)
- glucagon/E phosphorylates both enzymes both have opposite effects
- glycogen phosphorylase activity increases
- glycogen synthase activity decreases
- insulin results in dephosphorylation of both and opposite effects
- activate glycogen phosphorylase in absence of hormones
- immediate activation instead of hormonal
Glycogen Storage Diseases
- liver defective enzyme: hypoglycemia
- enzyme defective in muscle: weakness
Von Gierke
- can't release glucose between meals
- can't get glucose out of liver = hepatomegaly
- muscles will be ok
- no symptoms of muscle weakness
- consume corn starch between meals
Pompe
- liver is ok, continue make glucose
- no hypoglycemia symptoms
- entrapment of glycogen inside muscle cells
- enlarged tongue classic finding
Cori
- gluconeogenesis intact from other sources: hypoglycemia not as severe
- no glucose in muscles either: weakness
- usually no seizures
- muscle symptoms distinguish from Von Gierke
McArdle
- no liver problems, no hypoglycemis
- muscle difficulties
- can get muscle damage with exercise
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