Hydroxyl group of serin act as a side chain enzyme. Glucose 1- phosphate is converted to glucose 6- phosphate by the enzyme phosphoglucomutase.
Those tissues also house the enzyme glucose 6- phosphatase, which converted to glucose 6- phosphate into free glucose that is secreted into the blood , thereby restoring blood glucose levels to normal. It is intracelluar form of blood glucose.
Phosphorylation traps the glucose by placing a negative charge on the molecule , preventing its diffusion back across the cell membrane into the blood. Hexokinase enzyme acts on glucose and converts to glucose 6-phosphate.
