Final answer:
Glycogen phosphorylase enzyme is affected by allosteric effectors only when it is phosphorylated.
Step-by-step explanation:
Glycogen phosphorylase is the key enzyme responsible for glycogenolysis, which is the breakdown of glycogen into glucose. It acts on the α-1→4 glycosidic linkages of glycogen, releasing glucose units one by one. The enzyme is regulated by various factors including phosphorylation and allosteric effectors.
When glycogen phosphorylase is phosphorylated by phosphorylase kinase, it becomes active and can catalyze the hydrolysis of glycogen into glucose-1-phosphate. This process is important in providing glucose for the fight-or-flight response.
Allosteric effectors can also affect the activity of glycogen phosphorylase. It is true that allosteric effectors can only affect the enzyme if it is phosphorylated. This means that the phosphorylation status of glycogen phosphorylase plays a role in its sensitivity to allosteric regulation.