Glycogen Degradation Part I

This flashcard set covers the vocabulary and key enzymatic processes involved in the breakdown of glycogen in human metabolism, specifically focusing on the differences between liver and muscle tissues.

Glycogen

A highly branched homopolymer of glucose present in all tissues, with the largest stores located in the liver and muscle.

Liver Glycogen

Glycogen stores that are broken down to release glucose into the blood to provide energy for the brain and red blood cells.

Muscle Glycogen

Glycogen stores that are mobilized to provide energy specifically for muscle contraction.

$\alpha$-1,4 linkage

The glycosidic bond type that connects glucose residues in the linear chains of a glycogen molecule.

$\alpha$-1,6 linkage

The glycosidic bond type found at the branch points of the glycogen homopolymer.

Glycogen Phosphorylase

The enzyme that catalyzes the phosphorolysis of glycogen to produce glucose 1-phosphate using orthophosphate ($HPO_4^{2-}$).

Glucose 1-phosphate

The product released from glycogen by the action of phosphorylase during degradation.

Transferase

An enzyme involved in glycogen remodeling that shifts a block of three glucosyl residues from one outer branch to another.

$\alpha$-1,6-Glucosidase

A debranching enzyme that uses water ($H_2O$) to hydrolyze the $\alpha$-1,6 glycosidic bond, releasing free glucose.

Phosphoglucomutase

The enzyme responsible for the conversion of glucose 1-phosphate to glucose 6-phosphate.

Glucose 1,6-bisphosphate

The catalytic intermediate formed by phosphoglucomutase during the interconversion of glucose 1-phosphate and glucose 6-phosphate.

Glucose 6-phosphatase

A hydrolytic enzyme found in the liver that generates free glucose from glucose 6-phosphate, allowing it to be released into the blood.