Glycogen metabolism Flashcards
Recalls the steps of glycogen degradation and glycogen synthesis
Describes the reciprocal regulationof
glycogen metabolism
Recounts the hormonal regulation of glycogen metabolism
What is a Kinase?
an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule.
What is a Phosphatase?
an enzyme that catalyzes the hydrolysis of organic phosphate
Glycongen is a branced homoploymer of _
glucose
Glycogen is mainly found in the _ as it does what?
To maintain blood-glucose
Glycogen is found in the _ and the _ and its use to _ _ _ and in the _ for _
Mainly in liver (to maintain blood-glucose) and muscle (for ATP), bust most tissues have it
Glycogen is used for energy storage in what state?
Fed state
in what organisms is glycongen found in?
bacteria, archaea, and eukaryotes
Glycogen is make of 1,4 linkages with the branch points makewith _ _ _
alpha 1,6 linkages.
what are the ends of glycogen
reducing end and no reducing end
How do you know you are looking at a reducing end.
is the one with the hemiactal that helps open it up.
When do we break down glycongen?
in between meals
and exercise
When do we metabolize Glycogen?
Before Gluconeogenesis
Glycogen Metabolism is _ Regulated by Hormones?
Glycogen Metabolism is Reciprocally Regulated by Hormones
Glycogenolyis ( Glycogen degradation) is regulated by what hormome in the fasting state?
Glucogon
Glycogenolyis ( Glycogen degradation) is regulated by what hormome in the fatigued muscle state?
Epinephrine
In Glycogenolysis (Glycogen Degradation) wha is off and what s on?
(+) on glycogen degration
(-) off glycogen synthesis
In Glycogenesis (Glycogen Synthesis)
what is the Hormone? this would be the fed state.
Insulin
In Glycogenesis (Glycogen Synthesis) the fed state what is off and what is on?
(+) on glycogen syntheis
(-) off glycogen degradation
Glycogen Metabolism is requlated by _ _ in the _ and in the _ it is regulated by _
Glycogen Metabolism is requlated by charged state in the mussle and in the liver it is regulated by hormones
When fasting or inbetween meals you body will secreate _ . This hormone does simulates what _
When fasting or inbetween meals you body will secreate glucagon. This hormone does simulates what glycogen degradation.
Glycogenesis (Glycogen Synthesis)
happends _ _ _ and you screate _ and stimlate _ synthesis _ and inhibit _ degreation.
Glycogenesis (Glycogen Synthesis) happends after a meal and you stimluate glycogen synthsis and inhibit glycogen degreation.
In Glycogenolysis what are the 3 major emzymes
Glycogen Phosphorylase Debranching enzyme
a-1,6-Glucosidase
What is the end product of Glycognolysis?
Glucose 1- Phosphate
Glucose 1- Phosphate is catalyzed by _ _ and a _ enzyme.
Glycogen phosphorlase and a debranching enzyme.
Glucose 1- Phosphate is converted to _
Glucose 6- phosphate
What is are the fates of Glucose 6- phosphate and fill in the blanks
Glycoloysis
Liver
Pentose Phosphate pathway
what does Glycogen phosphorylase
use to catalyze a _ _
Phosphorolysis reaction
Glycogen phosphorylase starts at the _ ends and only cleaves -, bonds
Glycogen phosphorylase starts at the nonreducing ends and only cleaves a-1,4 glycosidic bonds.
Glycogen phosphorylase
runs in to an obstacle at what point?
at the branch point
Explain how the debrancing Enzyme works?
Phosphorylase starts at the non-reducing end
Then starts cleaving off residues but when is gets to four residues form the branch point.
pops off and transferase comes in and takes the last (3) of the four residues off and moves them to an new core and a-1,6 Glucosidase will have phosphorlase come in and the process will repeat.
Glycogen phosphorylase uses _ to do its job.
Pi and has a simple binging cite.
Regulation of Glycogenolysis
energy charge state of cell
is respnsive to insulin, epinephrine, and glucagon
what is the primary control point of Glycogen Metabolism?
Glycogen Phosphorylase
what are the ways that Glycogen Metabolism is controlled?
Primary control point is Glycogen Phosphorylase:
-senses energy charge state of cell
-is responsive to insulin, epinephrine, and glucagon
Regulation of liver and muscle phophoryalse compare and contrast. These are isozymes.
Allosteric Regulation of Glycogen phosphorylase by Phosphorylation: (liver and muscle enzyme can both be in either a or b form)
Liver phosphorylase
R and T state (glucose)
Phosphorylated
(usually active; phosphorylase a;)
Mussle phosphorylase
R and T state (AMP)
(usually inactive; phosphorylase b; muscle)
a to b is a function of if it is
what is the defalt state in the liver and is it actave or not active.
Phosphorylase a is the defalt state and it active.
what is the defalt state in the muscle and is it actave or not active.
usually inactive: phosphorylase b
Alot of glucose around do you need to be breaking down glucose? Would glucose activate or deactivate these enzymes?
No they would deactivate the enzymes and it would be in the T state.
Phosphorylase b to a can happen via _
Phosphorylase b to a can happen via phosphorylation
Phosphorylase b to a can happen via phosphorylation which Phosphorylase b is the defalt state of muslce phosphorlase can be in the _ state and _ state. What are the modulators for this?
R and T state
AMP
ATP
Glucose 6-phosphate
Phosphorylase a go threw and _ and _ state transition. What is the way that is is modlated in the liver.
R and T state and is modlated in the liver by glucose
Phosphorylase bto acan happen via phosphorylation the primary control for b –> a is _.
Hormonal primary contoral b –> a
If you have alot of ATP around do you need to be breaking down glycogen? and why?
No becasue breaking down glycogen make glucose and goes to glycolysis and the Kreb cycle -> ECT-> and
If you have alot of ATP around what state would Phosphorylase b is usually be in?
The T state
If you have alot of AMP around what state would Phosphorylase b is usually be in?
T state
If you have alot of G6P around what state would Phosphorylase b is usually be in?
T state
Phosphorylase a is _ and the _ state of the liver.
Phosphorylase a is active and the defalt state of the liver phosphorylase
Phosphorylase b is usually _ b/c the equilibrium Favors the _ state.
Phosphorylase b is usually inactive b/c the equilibrium Favors the R state.
inactive
Phosphorylase b is usually _ b/c the equilibrium Favors the _ state.
Phosphorylase b is usually inactive b/c the equilibrium Favors the T state.
inactive
Phosphorylase b is located in the _ and Phosphorylase a is located in the _.
Phosphorylase b mussle
Phosphorylase a liver
Know this
R -T is glucose shift to T state
liver
R -T is glucose shift to T state
mussle
If you have alot of AMP around do you need to be breaking down glycogen. what state with AMP around?
Yes, b/c is means you’ve gone throught all your ATP and now you have AMP around is going to shut the T state to the R state.
In the muscle what will make the R state go to the T state.
ATP and Glucose 6-phosphate.
Expain what is means that phosphorylase is regulated by phosprylation by phosphorylase kinase.
Protein Kinase A does the phosphorylation for regulation. Purple is active abd Blue inactive the goal is to activate phosphorylase. when we need to break down glycogen when our blood gulcose it low/exercising/ in bwtween meals.
Hormal siganl signal transduction cascase activng cAMP - Portoine Kinase A -> phosporylase Kinase -> phosphirylase a
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