A sample of glycogen from a patient with liver disease is...

Key Concepts

Debranching Enzyme

The debranching enzyme is essential for complete glycogenolysis as it resolves the branch points in glycogen. It has two distinct activities: a transferase component that shifts a small oligoglucose chain from a branch to a nearby chain, and an ?-1,6-glucosidase component that hydrolyzes the remaining ?-1,6 bond at the branch point, releasing free glucose. Deficiency in this enzyme impairs the removal of branch points, leading to abnormal glycogen structure.

Metabolic Disorders of Glycogen Degradation

Metabolic disorders involving deficiencies in enzymes of glycogenolysis, such as a debranching enzyme deficiency, disrupt the normal production of glucose from glycogen. This imbalance results in an abnormal ratio of glucose derivatives produced during the breakdown process and is exemplified in conditions like Cori disease, where the inability to effectively remove branch points leads to the accumulation of limit dextrin-like structures in the liver.

Glycogenolysis

Glycogenolysis is the biochemical process of breaking down glycogen into glucose units to meet energy demands. This process involves cleaving the ?-1,4-glycosidic bonds in the linear chains of glycogen and dealing with branch points, and it is tightly regulated to maintain blood glucose levels, especially in the liver and muscle tissues.

Glycogen Phosphorylase

Glycogen phosphorylase is the key enzyme that initiates glycogenolysis by catalyzing the cleavage of ?-1,4-glycosidic bonds to release glucose-1-phosphate. It acts sequentially along a linear chain until it approaches a branch point, hence playing a central role in mobilizing stored carbohydrates.

Transcript

0:00 Hello there students.

00:01 Today we're going to talk more about glycogen in the chapter about glycogen metabolism.

00:13 So before we continue on, because for one of the questions, they brought up about a sample of glycogen from the patient with a liver disease was incubated with orthrophosphate.

00:35 Phosphorfluoritis and transference and the branching enzyme.

00:41 And to go further more about this part, how the process will work if you're dealing with somebody whose liver is healthy, that the process, when you're dealing with alpha -16 glycositis, because it's basically a is basically known as a branching enzyme that hydrolyzed the alpha -16 glycosidic bond.

01:20 And i'm just showing this process how you see with the glycogen, how one is catalyzed by water and alpha -16 glycositis, how it ends up producing glucose and glycosin, whereas n1 residue.

01:35 And a better understanding of it where they did a remodeling of the process where you see that how the linkage for alpha -14 and alpha -16 linkage.

01:56 The alpha -14 is actually a glycosidic bond, each branch.

02:07 And how they are cleaved by the phosphorylis, where you end up leaving four residues, i mean four residues along the side of each branch, which you can see when it goes down at that process.

02:30 They see what happens out of that process.

02:32 It goes down here.

02:39 Yeah, okay, when it goes down there, my bad.

02:41 And how and then when the process comes down when it comes for the transfer this whole process where it shifts the blocks of three glue glucosol residues from one outer branch to the other and with the reaction between the link the blue and green links that is broken into a new alpha a link between the blue and the yellow residue where it ends up forming a linear and it's forming a linear structure which is basically what the transfer is in alpha one six glucositis that's basically the point that they do that which paves the way for further cleavage by phosphorylis...

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