Answer:
to prevent the formation of glucose,
to maintain energy supplies in muscle cells
to prevent energy waste by conserving the ATP ATP that would be needed to phosphorylate glucose
Explanation:
Glycogenlysis,the breakdown of glycogen involves the activities of glycogen phosphorylase. This enzyme phosphorylated glycogen to glucose-1-phosphate. The latter in presence of enzyme phosphoglucomutase is converted to Glucose-6-phosphate. (GP6)
GP6 enters glycolysis straight, to produce pyruvate.This step has shunted ATPs consumption of the usual glucose phosphoryaltion of the glycolytic pathway , thus conserving more energy for the muscles cells.
However if the glycogen phosphate active site was exposed to water, it will be hydrolyzed to glucose,( instead of glucose-1-phosphate).The glucose will pass through the normal ATPs consuming glycolytic pathways, losing more energy.
Therefore to prevent glucose formation, to conserve energy for immediate availability to ever demanding muscles cells, water is excluded from the active site of glycogen phosphorylase.