Where in the body is Glycogen mainly stored?
In the liver and muscles
What are the two types of glucose polysaccharide linkages?
alpha(1->4) makes long chains
alpha(1->6) makes branches
The more _____ ends you have, the ______ you build up and break down glucose
More, quicker
Glycogen Metabolism
-Review slide 4 and practice drawing the mech?
When does glycogen breakdown happen?
During the four Fs and low blood sugar
What is phosphorolysis?
Using a phosphate to break a bond
This enzyme cleaves an alpha (1->4) linkage from nonreducing ends. Product is a glucose 1-phosphate
Glycogen phosphorylase
What is the difference between Phosphatase and Phosphorylase?
Phosphatase removes the Phosphate
Phosphorylase uses phosphate to cleave a bond
This enzyme removes G1P until 3-4 residues away from an alpha (1->6) branch point.
Glycogen phosphorylase
Describe the steps of the debranching enzyme
-A transferase transfers the last 3 residues to the nonreducing end of the longer chain
-A glucosidase hydrolyzes an alpha(1->6) linkage to cleave off the glucose
This enzyme catalyzes a reversible isomerization from G1P to G6P
Phosphoglucomutase
What happens when there is lots of glucose and ATP?
Glycogen Synthesis
What are the steps to Glycogen Synthesis
Phosphoglucomutase (Activation), Glycogen synthase (Elongation), Glycogen branching enzyme (Branching),
What is Glycogenin?
A protein with Tyrosine residue which adds the Tyr, adds 6-7 more UDP glucose and adds branching
Name the regulation when one pathway is on while the opposite is off
Reciprocal regulation
Which regulation has G6P determine what is on and off
Allosteric Regulation
In covalent modification...
Phosphorylation of glycogen phosphorylase: on
Phosphorylation of glycogen synthase: off
Glycogen Phosphorylase is in the R state when Glycogen Phosphorylase is _____
On
What hormones do Glycogen Phosphorylase activate?
Glucagon and Epinephrine
Explain the different types of Muscle fibers
Slow twitch muscles are good for endurance while fast twitch muscles are good for sprinting short distances. Can be tested by just running and seeing how you feel