L07 Chem 481 Lecture Notes - Lecture 23: Glycogen Synthase, Pyrophosphate, Glycogenin
15 Apr 2017
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Removes 6 glucose molecules (uses 6 phosphates to make 6 g1-p) Leaves 4 glucose molecules at the end (sterics block it). Stops 4 glucoses away from branch point limit dextrin . Having both functions speeds up the enzyme activity. Moves 3 of the glucose molecules to another branch. Converting (1->4) bonds to (1->4) bonds requires essentially no energy, so it is thermodynamically a very favorable process. However, moving the last glucose which is an (1->6) bond to a (1->4) bond would be moving uphill in energy, so it is energetically more favorable to simply hydrolyze the last glucose which is thermodynamically favorable. Hydrolyzes the last glucose which is an (1->6) bond. G1-p needs to be converted into g6-p for glycolysis. Phosphate starts out being attached to a serine. The hydroxyl group on the serine then attacks the phosphate attached to c6. Used if the g1p were to fall off like the other mutase enzymes.
