Glycogenolysis

Unlike glycogenesis, glycogenolysis is the  breakdown of glycogen. Glycogen is  broken down  in  the  liver and muscle catalysed  by  the  enzyme glycogen phosphorylase. Inorganic  phosphate (Pi)  is used  for  the  lysis and hence  is called  phosphorolysis. Phosphorylase specifically acts upon a 1 →4  linkage of  glycogen  to produce glucose-1- phosphate. The  removal of  al,4  glucosyl  residues continues  until about 4 glucose residues remain on either side of a-1,6  branch, then  the debranching enzyme  (amylo  a 1,6 glucosidase)  causes the hydrolytic splitting  of  a 1,6  linkages. Here free  glucose  is  formed (since no phosphate  is used  for  lysis).