Which type of glycosidic bond is formed by glycogen synthase upon the release of UDP during glycogen synthesis?

• A. β(1→4) glycosidic bond
• B. α(1→4) glycosidic bond
• C. α(1→6) glycosidic bond
• D. β(1→6) glycosidic bond

Answer: (B)

Verified step by step guidance

1. Understand the role of glycogen synthase: Glycogen synthase is the key enzyme responsible for elongating the glycogen chain during glycogen synthesis. It adds glucose residues to the growing glycogen molecule.
2. Recall the structure of glycogen: Glycogen is a branched polysaccharide composed of glucose units. The main chain is formed by α(1→4) glycosidic bonds, while the branch points are connected by α(1→6) glycosidic bonds.
3. Identify the specific bond formed by glycogen synthase: Glycogen synthase catalyzes the formation of α(1→4) glycosidic bonds by transferring glucose from UDP-glucose to the non-reducing end of the glycogen chain.
4. Eliminate incorrect options: β(1→4) and β(1→6) glycosidic bonds are not found in glycogen. α(1→6) glycosidic bonds are formed by a different enzyme, branching enzyme, not glycogen synthase.
5. Conclude the correct answer: The glycosidic bond formed by glycogen synthase during glycogen synthesis is the α(1→4) glycosidic bond.