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': 'The enzyme common to both glycogenolysis and glycogenesis is: \nSelect and explain. \nA. Glycogen phosphorylase, B. Glycogen synthase, C. Glucotransferase, D. Phosphoglucomutase', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D PhosphoglucomutaseThe combined action of phosphorylase and these other enzymes leads to the complete breakdown of glycogen. The reaction catalyzed by phosphoglucomutase is reversible, so that glucose 6-phosphate can be formed from glucose I-phosphate. In liver (and kidney), but not in muscle, glucose 6-phosphatase hydrolyzes glucose 6-phosphate, yielding glucose that is expoed, leading to an increase in the blood glucose concentration. "', 'role': 'assistant'}]