Glycogen has what type of linkage?

• A. alpha 1-4, 1-6
• B. alpha 1-2
• C. beta 1-4, 1-6
• D. alpha 1-3

Answer: (A)

Glycogen is a highly branched storage polymer of glucose. Its straight chains are formed by alpha-1,4 glycosidic bonds, while branches occur at alpha-1,6 glycosidic bonds. The alpha configuration (as opposed to beta) is what allows the glucose units to be digested quickly by enzymes like glycogen phosphorylase and debranching enzymes. The frequent branching from alpha-1,6 bonds increases solubility and provides many ends for rapid glucose release when energy is needed.