Bio Chemistry

BIOCHEMISTRY 3(2+1)

Lesson 18 : Gluconeogenesis

Glycogen Degradation

• Glucose residues of starch and glycogen released through enzymes called starch phosphorylases and glycogen phosphorylases.
• Catalyze phosphorolysis:




• Sequentially removes glucose residues from non-reducing ends of glycogen, but stops 4 glucose residues from branch point --> leaves a limit dextran.
• Limit dextran further degraded by glycogen-debranching enzyme (glucanotransferase activity)
• Each glucose molecule released from glycogen by debranching enzyme will yield 3 ATPs in glycolysis.