This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
[{'content': 'Enzyme regulated by phosphorylation \nSelect and explain. \nA. Glucokinase, B. Glycogen synthetase, C. Pyruvate dehydrogenase, D. Isocitrate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Glycogen Synthase catalyzes elongation of glycogen chains. Glycogen Synthase catalyzes transfer of the glucose moiety of UDP-glucose to the hydroxyl at C4 of the terminal residue of a glycogen chain to form a (1 4) glycosidic linkage (diagrams p. 633):glycogen (n residues) + UDP-glucose glycogen (n +1 residues) + UDPRef: DM Vasudevan, 6th edition, page no: 106', 'role': 'assistant'}]