Glycogen Metabolism and the Pentose Pathway Notes

Flashcards covering key terms and definitions related to Glycogen Metabolism and the Pentose Pathway.

Glycogen

The major form of carbohydrate storage in the liver and muscle of humans, consisting of glucose polymer with α-1,4 linked units and α-1,6 branches.

Phosphorylase a

An enzyme that cleaves glycogen at non-reducing ends, releasing glucose-1-P.

Phosphoglucomutase

An enzyme that converts glucose-1-P to glucose-6-P, which can enter the glycolysis pathway.

UDP-Glucose Pyrophosphorylase

An enzyme that catalyzes the reaction of glucose-1-P with UTP to form UDP-glucose and inorganic pyrophosphate.

Inorganic Pyrophosphatase

An enzyme that hydrolyzes pyrophosphate (PPi) into two inorganic phosphates, driving reactions toward product formation.

Glycogen Synthase

An enzyme that transfers a glucose unit from UDP-glucose to the non-reducing end of glycogen.

Hormones

Organic compounds synthesized in one tissue and transported through the blood to exert effects on metabolic processes in another tissue.

Epinephrine

A low molecular weight hormone derived from tyrosine that stimulates glycogen breakdown by activating phosphorylase a.

Adenylate Cyclase

An enzyme that converts ATP to cyclic AMP, acting as a second messenger in cellular signaling.

Pentose Phosphate Pathway

An alternate pathway to glycolysis providing NADPH and pentose sugars, involving oxidative and non-oxidative stages.

NADPH

Reducing power crucial for biosynthesis, produced in the oxidative stage of the pentose phosphate pathway.

Transketolase

An enzyme that transfers a two-carbon fragment in the non-oxidative phase of the pentose phosphate pathway.

Transaldolase

An enzyme that transfers a three-carbon fragment from sedoheptulose 7-phosphate to glyceraldehyde 3-phosphate.