- 1. Glycogen phosphorylase uses Pi (NOT H2O) attacking nonreducing ends, removing terminal glucose as G1P.
- - some energy is preserved in high energy phosphate ester (G1P
2. Glycogen phosphorylase acts repetitively until it reaches a point four glucose residues away from branching point (a,1,6) b/c of sterics!
3. Glycogen debranching enzyme: transfers 3 glucose units from limit branch
to main chain (dG = 0 b/c energies cancel out)
4. Last glucose unit is hydrolyzed and released as free glucose.
5. Phosphoglucomutase (has Ser residue w/ P group) G1P <---> G1,6BP <--> G6P. G6P can enter glycolysis or be released by liver as free glucose.