Integrated Metabolism Flashcards
Glycogen synthase and glycogen synthase kinase are both active when
Not phosphorylated
What does adenylate cyclase do
Catalyses the formation of cAMP from ATP
How is GPCR signalling downregulated
Ligands diffuse away. Intrinsic GTPase activity in the Gs subunit converts it back to the inactive (GDP bound) state, cAMP is metabolised by PDE, phosphatases remove phosphate groups on phosphorylated proteins
What is cAMP metabolised by
Phosphodiester enzyme
What does caffeine inhibit, hence its stimulatory action
PDE, so cAMP is not inhibited and continues to act as a second messenger
What is the difference between lipoprotein lipase and hormone sensitive lipase
LPL breaks TAGs from lipoproteins to store. Hormone sensitive lipase mobilises fats in cells to be used for energy
What bond does glycogen synthase make
a-1,4 glycosidic linkages
What bond does branching enzyme make
a-1,6 glycosidic linkages
When is glycogen mobilised into glucose by adrenaline
During exercise
When is glycogen mobilised into glucose by glucagon
When fasting
What does the brain use for fuel during starvation
1/2 glucose, 1/2 ketone bodies (essential to conserve protein)
What are the main ketone bodies produced during starvation
Acetoacetate and B-hydroxybutarate
