Sandbox Reserved 338: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 14: | Line 14: | ||
===Mechanism=== | ===Mechanism=== | ||
[[Image: | [[Image: Glycogen_breakdown_3.png|thumb|Figure 1. Diagram illustrating the breakdown of glycogen near an (α1→6) branch point, and the steps where the α-1,6-glycosidase and the α-1,4-transferase activity of the glycogen debranching enzyme takes place. Diagram adapted from <ref name="lehninger"/>.]] | ||
In human metabolism, glycogen breakdown involves several enzymes, two of which are glycogen phosphorylase and glycogen-debranching enzyme <ref name="lehninger">Nelson, D. and Cox, M. Lehninger Principles of Biochemistry (5th Ed.), W.H. Freeman and Company, New York (2008).</ref>. Glycogen phosphorylase is responsible for the successive removal of glucose 1-phosphate molecules at the non reducing ends of glycogen branches <ref name="lehninger"/>. However, this enzyme’s activity ceases when it has reached a point four glucose residues away from an (alpha 1→6) branch point. Upon this, the GDE takes over and catalyzes the transfer of three branched glucose units to the nonreducing end of another branch to yield an (α1→4) linkage. The α-1,6-glycosidase activity of the GDE liberates the non-transferred glucose unit involved in a (α 1→6) bond <ref name="lehninger"/>. | In human metabolism, glycogen breakdown involves several enzymes, two of which are glycogen phosphorylase and glycogen-debranching enzyme <ref name="lehninger">Nelson, D. and Cox, M. Lehninger Principles of Biochemistry (5th Ed.), W.H. Freeman and Company, New York (2008).</ref>. Glycogen phosphorylase is responsible for the successive removal of glucose 1-phosphate molecules at the non reducing ends of glycogen branches <ref name="lehninger"/>. However, this enzyme’s activity ceases when it has reached a point four glucose residues away from an (alpha 1→6) branch point. Upon this, the GDE takes over and catalyzes the transfer of three branched glucose units to the nonreducing end of another branch to yield an (α1→4) linkage. The α-1,6-glycosidase activity of the GDE liberates the non-transferred glucose unit involved in a (α 1→6) bond <ref name="lehninger"/>. | ||
