KIN 217 - glycogen synthesis chapter 25

UDP-glucose

what is the substrate for glycogen synthase UD

phosphoglucomutase

what is the common enzyme b/w glycogen breakdown and synthesis

UDP-glucose pyrophosphorylase

Uses UTP and glucose 1-phosphate to make UTP-glucose and pyrophosphate

reversible

the rxn of making UDP-glucose is

irreversible

the rxn of making pyrophosphate is

glycogen synthase

this is the key regulatory enzyme of glycogen synthesis

C-4 terminal residue

glycogen synthase will transfer glucose from UDP-glucose to the __________________ of glycogen chain

alpha,1-4

glycogen synthase will form what kind of bond to a glycogen chain

true

glycogen synthase can only add glucose to chain of 4 or more glucose residue

t or f

glycogenin

the glycogen priming enzyme that makes the alpha-1,4 glyosidic chain

branching enzyme

this enzyme makes a alpha 1-,6 linkage by breaking off the alpha-1,4 link with 7 glucose

11

the chain that was broken with the branching enzyme must have how many glucoses

4

the new alpha-1,6 link made by branching enzyme is how many residues inwards

glycogen synthase

what is the main regulated enzyme in glycogen synthesis

unphosphorylated a

glycogen synthase is active when in the _______________ form

phosphorylated b

glycogen synthase is inactive when in the _______________ form

g-6-p

glycogen synthase is allosterically controlled by what

T, R

when g-6-p binds to glycogen synthase it shifts b in ____ state to the ___ state of b form

glucagon/EP

glycogen synthesis is inhibited by what

inactive b

PKA phosphorylates glycogen synthase turning it to ___ form

glycogen synthase kinase

will also inhibit glycogen synthase along with PKA

inactive, PP1

when removing glucagon or EP what happens to PKA which causes what to become active

PP1

shifts glycogen metabolism to synthesis converting glycogen synthase to active form

phosphorylase kinase, glycogen phosphorylase

PP1 can inhibit glycogen degradation by removing phosphoryl groups from what

Gm

PP1 in the muscle has catalytic subunits where regulatory subunits bind it to called

GL

PP1 in the liver has catalytic subunits where regulatory subunits bind it to called

Gm

activated PKA will phosphorylate what in the muscle

dissociates

When activated PKA phosphorylates Gm what does PP1 do

false

not many tissues have inhibitors that inhibit PP1 when phosphorylated

t or f

insulin

_________ results in the phosphorylation and inactivation of glycogen synthase kinase

a

when insulin inactivates glycogen synthase kinase, PP1 can dephosphorylates what glycogen synthase turning it to the ____ form

GLUT 4

insulin also causes translocation of what to the cell surface

true

GLUT 4 receptors can activate glycogen synthase even in the b form

t or f

inhibited

high glucose levels in the liver or blood will cause glycogen degradation to be

stimulated

high glucose levels in the liver or blood will cause glycogen synthesis to be

glucose

the liver phosphorylase is sensitive to what

phosphorylase

glucose will inhibit what directly in the liver and the blood

synthase

glucose will activate what indirectly in the liver and blood

R, T

when glucose binds to glycogen phosphorylase it will shift the a form from _____ state to _____ state

phosphorylated serine

when T state is activated, it exposes what

false

the phosphorylated serine exposed by t state can is removed by PP1 with ATP to shift it to b form

t or f

dissociates from PP1

after enzyme is shifted to b form what happens to the phosphorylase

activates it

when phosphorylase is dissociated from PP1 what happens to PP1

b (inactive)

activating PP1 to remove Pi will turn phosphorylase to what form

a (active)

activating PP1 to remove Pi will turn synthase to what form

type 1

this type of diabetes is juvenile onset and occurs in younger people typically

beta cells

type 1 diabetes is an autoimmune attack on what cells

no production

due to beta cell destruction what happens to inulin

false

glucagon dysregulation also occurs a beta cells loss but it has no affect on alpha cells

t or f

urine

in type 1 diabetes where is glucose lost

ketoacidosis

what is the risk of type 1 diabetes as ketone body production occurs as tissues are not getting glucose

type 2 diabetes

this type of diabetes is more common in society and adults

resistance

this is due to insulin ______ which means the signaling pathway is overwhelmed

true

insulin will inhibit hormone sensitive lipase in adipose but there are less FA releases

t or f

true

the isolated south pacific island is known for the highest rates of type 2 diabetes

t or f