Glykogen metabolisme Flashcards
(22 cards)
Hvordan påvirker en høj koncentration af NADPH, pentose phosphate pathway
ved at inhibere omdannelsen af glukose 6-phosphate til 6-glucono-delta-lactone
Hvordan påvirker acetyl-CoA dens dannelse fra puruvat og dannelsen af oxaloactetate
Høj koncentration => inhibering
høj => stimulerer pyruvate carbóxylase til at producere oxaloacetat
Hvordan påvirker acetyl-CoA dens dannelse fra puruvat og dannelsen af oxaloactetate
Høj koncentration => inhibering
høj => stimulerer pyruvate carbóxylase til at producere oxaloacetat
glycose 6-phosphatase in liver, adipose tissue and muscles
yes, nope , nope
The last two don’t contribute to blood sugar
Where does the glucose for glycogen synthesis come from?
UDP-glucose
enzyme catalysing UDP-glucose formation
UDP-glucose phosphorylase
why is branching important in glycogen synthesis?
because the solubility increases + increase in the number of non-reducing ends to be acted upon by glycogen synthase and glycogen phosphorylase
what primes the initial sugar residues and the enzyme that caatalyses their assembly
glucogenin (glucosyltransferase activity)
When does the glycogen synthase take over in glycogen synthase?
When the glycogenin has synthesized a polymer of 8 residues
Where are the glucogenin placed and where are attache to
in B-particles and attached to the reducing ends
how is phosphorylase activated
cAMP increase pKA aktive phosphorylase B kinase active phosphorylase A active
Ca+ and glycogen
binds to calmodulin subunit in phosphorylase b activating it
glucose and glycogen
binds to phosphorylase a exposes the phosphoserin to PP1 and inactivates
when is synthase a active
unphosphorylated
when is synthase b inactive
phosphorylated
wha could be an allosteric activator of synthase
glucose 6- phosphate
glycogen synthase b to a is catalysed by
pp1 (phosphoprotein phosphatase 1)
what does insulin do to GSK3 and pp1
pp1 is activated. GSK3 is inhibited
phosphorylase and synthase
phosphorylase directly inhibits synthase
PP1 does not exist freely in the cytosol but bound to enzymes called
glycogen targetting enzymes
what does GSK3 do
phosphorylates synthase a and inactivates it
glycolysis is not turned off when when cAMP is high in …
myocytes
