Glycogen Synthesis and Metabolism

These flashcards cover key vocabulary and concepts in glycogen synthesis and metabolism.

Glycogen

A branched polymer of glucose used for energy storage in animals.

UDP-glucose

An activated form of glucose used as a donor in glycogen synthesis.

Glycogen synthase

The key enzyme that catalyzes the addition of glucose units from UDP-glucose to a growing glycogen chain.

Glycogen phosphorylase

The enzyme responsible for breaking down glycogen into glucose 1-phosphate.

Glycogenin

A protein that acts as a primer for glycogen synthesis.

Branching enzyme

An enzyme that introduces alpha-1,6 linkages, creating branches in glycogen.

Allosteric regulation

Regulation of an enzyme's activity through the binding of molecules at sites other than the active site.

Protein kinase A (PKA)

An enzyme that phosphorylates target proteins, involved in the regulation of glycogen metabolism.

Insulin

A hormone that stimulates glycogen synthesis by promoting glucose uptake and inhibiting glycogen degradation.

Glucagon

A hormone that signals the liver to break down glycogen and increase blood glucose levels.

cAMP

Cyclic adenosine monophosphate; a secondary messenger that mediates hormonal responses in cells.

Phosphorylation

The addition of a phosphate group to a molecule, often used in signal transduction and metabolic regulation.

Dephosphorylation

The removal of a phosphate group from a molecule, often reversing the effects of phosphorylation.

Pyrophosphate

A molecule released during the synthesis of UDP-glucose; drives the reaction forward.

Nonreducing terminal residue

The end of a glycogen chain that does not have a free hydroxyl group available for further elongation.

Glycogen storage diseases

Disorders caused by enzyme deficiencies affecting glycogen metabolism.

Von Gierke disease

A glycogen-storage disease caused by a deficiency of glucose 6-phosphatase.

Pompe disease

A glycogen-storage disease causing lysosomal accumulation of glycogen due to a deficiency of a hydrolytic enzyme.

Cori disease

A glycogen-storage disorder characterized by abnormal structure and increased amount of glycogen.

McArdle disease

A glycogen-storage disease due to a deficiency in muscle phosphorylase, causing exercise intolerance.

Epinephrine

A hormone that triggers glycogen breakdown and elevates blood glucose during stress.

Phosphofructokinase

An enzyme that regulates glycolysis impacted by the concentration of fructose 2,6-bisphosphate.

Glycogen synthase kinase (GSK)

An enzyme that phosphorylates glycogen synthase, inhibiting its activity.

Protein phosphatase 1 (PP1)

An enzyme that dephosphorylates glycogen synthase and phosphorylase, regulating glycogen metabolism.

Super compensation

The phenomenon where glycogen stores exceed normal levels following carbohydrate-rich meals after depletion.

Hydrolysis

The breakdown of a compound due to reaction with water, often used to cleave phosphoester bonds.

Blood-glucose concentration

The amount of glucose present in the blood, tightly regulated by hormonal signaling.

Glycogen metabolism

The processes of glycogen synthesis and degradation, regulated by hormones and energy needs.

Liver phosphorylase a

An enzyme form in the liver that acts as a glucose sensor, regulating glycogen metabolism.

Glycogen synthesis

The process of forming glycogen from glucose, primarily through the action of glycogen synthase and UDP-glucose.

Glucose 1-phosphate

A product of glycogen breakdown that can be converted into glucose 6-phosphate.

Glucose transporters (GLUT4)

Proteins that facilitate the uptake of glucose into cells, especially under the influence of insulin.