This reaction appears to occur in a combined acid/base mechanism. It starts with the one glutamic acid in the acid state. The proton is effectively donated to the oxygen of the glycosidic bond. AS the pair of electrons from the C-O bond swing out to get the proton, it leaves behind a postitively charged carbon which is easily attacked by the nearby glutamic acid that is in the base state.
The results of the previous step are shown. The glycogen has broken and the C6 glucose is protonated appropriately. A covalent bond between the branch of the glycogen and the enzyme has been formed.
The glutamate that was originally in the acid state is now a base, which pulls on the proton that is on the C6 hydroxyl group. This makes the oxygen able to atttack the covalent bond between the enzme and the branch of the glycogen.
The results of the previous step are shown. The 1→4 glycosidic bond has formed and all the glutamates are back to their original protonation state.
| Reaction | Rationale | Thermodynamics | Mechanism | Pictures | JMOL |
|
Enzyme Name |
Debranching Enzyme | |
Reaction Catalyzed |
moves a polymer segment connected to a 1→6 branch to the end of a 1→4 polymer segment
| |
Reaction Type |
group Transfer Reaction | |
Pathway Involvement |
Glycogen Breakdown |
|
Cofactors/Cosubstrates |
None. | |
