Arrange the steps of glycogenolysis in sequence: A. Formation of limit dextrins B. Transfer of glucose residues from branched chain to neighbouring straight chain (Glucan Transferase) C. Break down alpha(1-4) bond from non reducing end D. Break down of alpha (1-6)bond
Break down alpha(1-4) bond from non reducing end | Formation of limit dextrins | Transfer of glucose residues from branched chain to neighbouring straight chain (Glucan Transferase) | Break down of alpha (1-6)bond Glycogen Phosphorylase breaks alpha(1-4) bonds, staing from non-reducing end, till four glucose residues are left at branch point. Glycogen Phosphorylase can break glucose residues in a chain only till 4 glucose residues are left in the branched chain phosphorylase breaks only alpha(1- 4) bonds and not alpha(1 - 6) bonds. The structure left is known as Limit Dextrin. Glucan Transferase transfers 3 glucose residues from 1 chain to the neighbouring chain. (Oligo alpha (1 - 4)or alpha (1- 4) glucan transferase or 4:4 transferase) Debranching enzyme: Breaks a(1- 6) bond, which is present at the staing of a branched chain. This glucose is released in the form of free glucose. ( Amylo alpha (1- 6) glucosidase )
A - D - B- C
D - C - B- A
D - B - C- A
C - A - B- D
Glycogen