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 co-factor for glycogen phosphorylase in glycogenolysis is: \nSelect and explain. \nA. Thiamine pyrophosphate, B. Pyridoxal phosphate, C. Citrate, D. FAD', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Glycogen phosphorylase catalyses the rate limiting step in glycogenolysis by catalyzing the phosphorolytic cleavage of glycogen to yield glucose 1-phosphate. Glycogen phosphorylase requires pyridoxal phosphate as its coenzyme.', 'role': 'assistant'}]