KIN 217 - glycogen degradation - chapter 24

glycogen

a highly branched polymer of glucose in all tissues but mainly stored in liver and muscle

liver

which store is more concentrated in glycogen

muscle

which store has a larger poll in glycogen

cytoplasm

where are glycogen granules formed and stroed

alpha- 1,4

glycogen are straight chains with _________ glyosidic bonds

glycogenin

what is at the core of a glycogen

nonreducing

_______ ends of chains on the exterior structure of glycogen

4

how many enzymes are involved to make g-6-p from glycogen

glycogen phosphorylase

what is the rate limiting enzyme of glycogen degradation

glycogen phosphorylase

this enzyme degrades glycogen from nonreducing ends to make glucose 1-phosphate

orthophosphate

the reaction glycogen phosphorylate does breaks the alpha-1,4 bond using what

glucose-1-phosphate

this molecule is the product from the enzyme glycogen phosphorylase and has a phosphate already on glucose to stay inside cell

true

the issue with using glycogen phosphorylase is that it can't cleave 4 glucose residues near branch points

t or f

transferase

because glycogen can't cleave the 4 glucose residues, it will use ____ to shift oligosaccharide closer to branch point

alpha 1-4

what kind of bond does glycogen phosphorylase break

alpha-1,6

what kind of bond that glycogen have that needs to be cut off

3

how many glucose residues move with the transferase enzyme

alpha-1,6-glucosidase

what enzyme debranches the alpha-1,6 bond at branch point

H2O

what does alpha-1,6-glucosidase use to break the alpha bond

false

a glucose with a phosphate is released when using alpha-1,6-glucosidase

t or f

phosphoglucomutase

this enzyme converts glucose-1-phosphate to glucose-6-phosphate for glycolysis

serine

what phosphorylated residue does phosphoglucomutase have

glucose-1,6-BP

what intermediate is made when phosphoglucomutase is used

hexokinase/glucokinase

what enzymes can add 6-phosphate to free glucose from debranching enzyme

true

the liver contains glucose-6-phosphatease

t or f

free glucose

glucose-6-phosphate generates what using the enzyme glucose-6-phosphatase in the liver

false

glucose-6-phosphotase can be found in other tissues

t or f

more active

the a form of glycogen phosphorylase is what

less active

the b form of glycogen phosphorylase is what

phosphorylated serine

what does the a form of glycogen phosphorylase have

T state

in b form, glycogen phosphorylase will favour

R state

in a form, glycogen phosphorylase will favour

B, T

what form (a or b) is the default form in muscles in what state (t or r)

low

energy is _____ in muscles when AMP conc increases causing AMP to bind to enzyme shifting to R state

high

energy is _____ in muscles when AMP conc increases causing ATP or g-6-p to bind to enzyme shifting to T state

Epinephrine

_______ signals phosphorylates to active a form regardless of AMP, ATP, or g-6-p

a, R

in the liver the default form is ______ while the default state is _______

glucose

what is a negative feedback regulator of liver glycoen phosphorylase to shift it into T state

true

glycogen phosphorylase does not use AMP regulation in the liver

t or f

glucagon/EP

this regulator phosphorylates serine residue on glycogen phosphorylase in the liver

insulin

this regulator dephosphorylates serine residue on glycogen phosphorylase in the liver

deactivate

insulin will ______ glycogen phosphorylase in the liver

activate

glucagon/EP will ______ glycogen phosphorylase in the liver

phosphorylase kinase

this enzyme will shift b state to the a state

phosphorylation or Ca2+ binding

how is phosphorylase kinase activated

true

when phosphorylase kinase is phosphorylated and has Ca2+ it is maximally active

t or f

PKA

how is phosphorylase kinase phosphorylated

calmodulin

the delta subunit of phosphorylase is the calcium sensor ______

glucagon and epinephrine

in the liver what molecule(s) can regulate glycogen breakdown

epinephrine

in the muscle what molecule(s) can regulate glycogen breakdown

exercise

when does glycogen breakdown occur in the muscle

fasting

when does glycogen breakdown occur in the liver

cAMP

EP uses a G-protein cascade for the production of what

PKA

what does cAMP activate

turn it to a

when PKA is activated what does it do to glycogen phosphorylase b

degrade

phosphorylase in a state will ______ glycogen

iiB

these muscle type are reliant on glucose and glycolysis

I

these muscle type are reliant on fats and oxygen for oxidative phosphorylation

true

fatigue is associated with depleted glycogen reserves

t or f