Glucogenolysis
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This document summarizes glycogenolysis, the breakdown of glycogen to glucose. Glycogen is the storage form of glucose in animals, found mainly in the liver and muscles. Glycogenolysis occurs in the liver and muscles to meet energy demands when blood glucose levels fall. It involves three main steps: 1) Glycogen phosphorylase cleaves glycogen molecules into glucose-1-phosphate. 2) A debranching enzyme further breaks down the glycogen molecules. 3) Glucose-1-phosphate is converted to glucose-6-phosphate and glucose to be used for energy. The process ultimately breaks down glycogen stores into glucose to regulate blood sugar levels.
Glucogenolysis
- 1. GLYCOGENOLYSIS ANAGHA P JAYAN AND Dr. Kayeen Vadakkan Department of Biotechnology ST.MARY’S COLLEGE, THRISSUR
- 2. GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR Glycogen Multibranched subunit of glucose. Serve as a form of energy storage in humans, animals, fungi etc. consist of 2 types of linkages, alfa(1 4)linear linkage alfa(1 6) branching linkage. Storage Storage form of glucose in animals (animal starch). Granular form , high in liver (6-8%) and muscles(1-2%).
- 3. Glycogenolysis Breakdown of glycogen to glucose 1 phosphate and glucose in liver and muscles. To meet the immediate energy demands of the body or when the blood glucose level is low. Steps involved in glycogenolysis. Step-1 action 0f glycogen phosphorylase. Alpha-1,4-glycsidic bonds(from non-reducing ends)are cleaved sequentially by enzyme glycogen phosphorylase to yield Gluc-1-phosphate . This proses is called phosphorolysis. Limits : degrades the glycogen molecules until 4 glucose residues remain on each chin before a branch point (stops at 4 glucose residue GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR
- 4. The glycogen so formed is known as limit dextrin which can not be further degraded by phosphorylase. Step-2 action of debranching enzyme The branch of glycogen are cleaved by debranching enzyme(bifunctional enzyme ) . GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR
- 5. 1. Glycosyl 4:4 transferase (oligo alpha 1,4→1,4 glucan transferase) Activity removes a fragment of 3 or 4 glucose residues from a branch and transfer them to another chain. 2.Amylo alpha-1,6-glucosidase Breaks the alpha-1,6-bond at the branch with a single glucose residue. Step-3 Formation of glucose -6-phosphate and glucose Combined action of glycogen phosphorylase and branching enzyme free glucose(8:1 ratio) are produced . Glucose- 1-phosphate is converted to glucose-6-phosphate by the enzyme phosphoglucomutase. In liver, kidney, and intestine Glu-6-p is converted in to glucose. GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR
- 6. GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR
- 7. GLYCOGENOLYSIS, ANAGHA P JAYAN , ST.MARY’S COLLEGE - THRISSUR THANK YOU