BIOC 3110 Lecture Notes - Lecture 24: Glycogen Phosphorylase, Glycosidic Bond, Phosphorylase

• School: University of Iowa
• Department: Biochemistry
• Course: BIOC 3110
• Professor: marcwold

Document Summary

Breakdown in muscle is used strictly for local use. Breakdown in liver is used to maintain blood-glucose levels. What types of glycosidic bonds connect the residues? globally: alpha-1,4 o-glycosidic bonds make linear structure, alpha-1,6 bonds link branches, the bonds are broken at the non-reducing ends of glucose (the ends with free aldehyde, -oh carbon) What 6 (3+3) enzyme activities are necessary for degradation of glycogen: big 3: Glycogen phosphorylase-cleaves glucose from the non- reducing end of glycogen chain. Cleaves the alpha-1,4 glycosidic bond while also transferring a phosphate. Cannot remove residues close to branch points. Transferase-moves 3 glucose residues onto another portion of a chain. Moves the chain piece onto a chain end to create a longer chain that allows phosphorylase to release more of them. Alpha-1,6-glucosidase (debranching enzyme)- hydrolyzes the alpha-1,6 bonds to release the single isolated glucose left on a branch point. This releases free glucose: little 3: Hexokinase-phosphorylates free glucose released from branch points to make glucose-1-phosphate.