Glykogen metabolisme Flashcards

1
Q

Hvordan påvirker en høj koncentration af NADPH, pentose phosphate pathway

A

ved at inhibere omdannelsen af glukose 6-phosphate til 6-glucono-delta-lactone

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2
Q

Hvordan påvirker acetyl-CoA dens dannelse fra puruvat og dannelsen af oxaloactetate

A

Høj koncentration => inhibering

høj => stimulerer pyruvate carbóxylase til at producere oxaloacetat

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3
Q

Hvordan påvirker acetyl-CoA dens dannelse fra puruvat og dannelsen af oxaloactetate

A

Høj koncentration => inhibering

høj => stimulerer pyruvate carbóxylase til at producere oxaloacetat

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4
Q

glycose 6-phosphatase in liver, adipose tissue and muscles

A

yes, nope , nope

The last two don’t contribute to blood sugar

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5
Q

Where does the glucose for glycogen synthesis come from?

A

UDP-glucose

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6
Q

enzyme catalysing UDP-glucose formation

A

UDP-glucose phosphorylase

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7
Q

why is branching important in glycogen synthesis?

A

because the solubility increases + increase in the number of non-reducing ends to be acted upon by glycogen synthase and glycogen phosphorylase

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8
Q

what primes the initial sugar residues and the enzyme that caatalyses their assembly

A

glucogenin (glucosyltransferase activity)

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9
Q

When does the glycogen synthase take over in glycogen synthase?

A

When the glycogenin has synthesized a polymer of 8 residues

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10
Q

Where are the glucogenin placed and where are attache to

A

in B-particles and attached to the reducing ends

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11
Q

how is phosphorylase activated

A

cAMP increase pKA aktive phosphorylase B kinase active phosphorylase A active

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12
Q

Ca+ and glycogen

A

binds to calmodulin subunit in phosphorylase b activating it

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13
Q

glucose and glycogen

A

binds to phosphorylase a exposes the phosphoserin to PP1 and inactivates

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14
Q

when is synthase a active

A

unphosphorylated

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15
Q

when is synthase b inactive

A

phosphorylated

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16
Q

wha could be an allosteric activator of synthase

A

glucose 6- phosphate

17
Q

glycogen synthase b to a is catalysed by

A

pp1 (phosphoprotein phosphatase 1)

18
Q

what does insulin do to GSK3 and pp1

A

pp1 is activated. GSK3 is inhibited

19
Q

phosphorylase and synthase

A

phosphorylase directly inhibits synthase

20
Q

PP1 does not exist freely in the cytosol but bound to enzymes called

A

glycogen targetting enzymes

21
Q

what does GSK3 do

A

phosphorylates synthase a and inactivates it

22
Q

glycolysis is not turned off when when cAMP is high in …

A

myocytes