This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'In muscle, Phosphorylase a is inactivated by \nSelect and explain. \nA. cAMP, B. Ca2+ ion, C. Glucose, D. ATP', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In the liver, the role of glycogen is to provide free glucose for export to maintain the blood concentration of glucose.\xa0\nIn muscle the role of glycogen is to provide a source of glucose-6-phosphate for glycolysis in response to the need for ATP for muscle contraction.\nIn both tissues, the enzyme is activated by phosphorylation catalyzed by phosphorylase kinase (to yield phosphorylase a) and inactivated by dephosphorylation catalyzed by phosphoprotein phosphatase (to yield phosphorylase b), in response to hormonal and other signals.\nThere is instantaneous overriding of this hormonal control. Active phosphorylase a in both tissues is allosterically inhibited by ATP and glucose-6-phosphate; in liver, but not muscle, free glucose is also an inhibitor.\u200b\n\nHarper 30th edition page 179', 'role': 'assistant'}]