BCMB 3100: Case 10 Review

Catabolic Pathways

• Deliver chemical energy in the form of ATP and NADH

• Breaks down macromolecules

Anabolic

• converts small molecules into macromolecules

Glycogenin

protein enzyme core of glycogen

Kinase

add a phosphate group

Phosphatase

removes phosphate groups

Glucose molecules are linked by

glycosidic bonds

A-1, 6 Linkages

linkages that form branches in glycogen

A-1, 4 Linkages

Links adjacent glucose molecules in a chain

Glycogenolysis

remodeling and deconstruction of glucose to make glucose 6-phosphate

Glycogen Phosphorylase

• DEGRADES glycogen

• Cuts A-1,4 linkages

• Creates Glucose 1-Phosphate

Transferase

• REMODELS glycogen

• transfer branch to glucose chain

A-1, 6-Glucosidase

• REMODELS Glycogen

• cuts A-1, 6-Linkages

Phosphoglucomutase

• Converts Glucose 1-Phosphate into Glucose 6-Phosphate by transferring a phosphate group

Enzyme involved in Glycogenolysis in the Liver

Glucose 6-Phosphatase

Glucose 6-Phosphatase

• converts glucose 6-phosphate into glucose

Types of Glycogen Phosphorylase Regulation

• Allosteric

• a/b Phosphorylation

Allosteric Regulation of Glycogen Phosphorylase

• High energy molecules call for more storage

• Low energy molecules signal release of more glucose

a/b Phosphorylation

• removing or adding a phosphate group to activate or inactivate

A-Form of Glucose Phosphorylase

• phosphorylated

• active

B-Form of Glucose Phosphorylase

• inactive

• dephosphorylated

Activation of Glycogen Phosphorylase

• converting b-form to a-form

what hormones indirectly activate Glycogen Phosphorylase

• Glucagon

• Epinephrine

Inhibition of Glycogen Phosphorylase

• PP1 dephosphorylates a-form to b-form

what hormones indirectly inactivate glycogen phosphorylase

• insulin

most active version of glycogen phosphorylase in the liver

• Phosphorylated

• A-Form

• Relaxed State

Default form of Glycogen Phosphorylase in Muscle

• B-Form

What shifts Glycogen Phosphorylase A from r-state to t-state

Binding of glucose molecule

What stimulates Phosphorylase Kinase in muscle

• calcium ions

glycogen synthesis

building of glycogen

Glycogen Synthesis is primed by

Glycogenin protein core

Glycogen Synthase

• TRANSFERS glucose chain to another growing chain

Branching Enzyme

• breaks a-1,4-linkages

• moves chain creating a-1, 6-linkage

PP1 and Glycogen Phosphorylase

• dephosphorylates converting a-form to b-form

• active to inactive

PP1 and Glycogen Synthase

• dephosphorylates b-form to a-form

• inactive to active