Glycogenesis pathway

[ "article:topic", "showtoc:no", "cssprint:dense", "autonumheader:yes2", "licenseversion:40", "glycogenesis", "glycogen synthase", "UDP-glucose pyrophosphorylase", "glycogenin", "glycogen branching enzyme", "authorname:jakubowski-flatt", "avatar@https://bio.libretexts.org/@api/deki/files/67680/Patty_Flatt.jpg" ] https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FBookshelves%2FBiochemistry%2FFundamentals_of_Biochemistry_(Jakubowski_and_Flatt)%2F02%253A_Unit_II-_Bioenergetics_and_Metabolism%2F15%253A_Glucose_Glycogen_and_Their_Metabolic_Regulation%2F15.02%253A_Glycogenesis Expand/collapse global hierarchy • Home • Bookshelves • Biochemistry • Fundamentals of Biochemistry (Jakubowski and Flatt) • Fundamentals of Biochemistry Vol. II - Bioenergetics and Metabolism • 15: Glucose, Glycogen, and Their Metabolic Regulation • 15.2: Glycogenesis Expand/collapse global location \( \newcommand\) • • • • • • • • Search Fundamentals of Biochemistry Introduction The process of forming glycogen is called glycogenesis and it requires the activity of six enzymes as illustrated inFigure \(\PageIndex \nonumber \] UTP--glucose-1-phosphate uridylyltransferase (orUDP-Glucose Pyrophosphorylase) The formation of the UDP-glucose required for the synthesis of the main chain of glycogen is mediated by UTP-glucose-1-phosphate uridylyltransferase(preferred name), which is also called UDP-glucose pyrophosphorylase (GalU or UGPase; EC 2.7.7.9). UGPase catalyzes the r...

glycogenolysis, process by which When blood glucose levels fall, as during fasting, there is an increase in glucagon secretion from the The vast majority of glucose that is released from glycogen comes from Epinephrine, similar to glucagon, stimulates glycogenolysis in the liver, resulting in the raising of the level of blood glucose. However, that process is generally initiated by the Compare

\( \newcommand\). Glycogen synthesis Glycogen synthesis begins with UDP-glucose phosphorylase, which combines the nucleotide uridine triphosphate (UTP) with glucose-1-phosphate to release pyrophosphate (PP i) and form UDP-glucose. The phosphoanhydride exchange reaction catalyzed by UDP-glucose phosphorylase is minimally exergonic. However, the pyrophosphate released is quickly hydrolyzed by inorganic pyrophosphatase, a ubiquitous cytosolic enzyme, in a highly exergonic reaction. This pyrophosphate hydrolysis is a mechanism utilized in many biosynthetic pathways to provide energy for otherwise endergonic reactions. In the next step, glycogen synthase attaches the UDP-glucose to the pre-existing glycogen chain with an α(1->4) linkage. It cannot join two individual glucoses together, only add to a pre-existing chain. This means that there must be some workaround for the first two glucoses: glycogenin is an enzyme that catalyzes the addition of UDP-glucose to itself, and can do so for up to seven UDP-glucose molecules, thus forming a short primer for glycogen synthase to work with. Furthermore, glycogen synthase can only add glucoses with an α(1->4) link. For branching to occur, a branching enzyme (specifically, amylo-(1,4->1,6)-transglycosylase is needed. This enzyme can transfer terminal chain segments to the 6-carbon hydroxyl of any glucose in a glycogen chain. However, the branches can only be added if there are at least 4 glucose residues between them, and if the originat...

glycogenolysis, process by which When blood glucose levels fall, as during fasting, there is an increase in glucagon secretion from the The vast majority of glucose that is released from glycogen comes from Epinephrine, similar to glucagon, stimulates glycogenolysis in the liver, resulting in the raising of the level of blood glucose. However, that process is generally initiated by the Compare

[ "article:topic", "showtoc:no", "cssprint:dense", "autonumheader:yes2", "licenseversion:40", "glycogenesis", "glycogen synthase", "UDP-glucose pyrophosphorylase", "glycogenin", "glycogen branching enzyme", "authorname:jakubowski-flatt", "avatar@https://bio.libretexts.org/@api/deki/files/67680/Patty_Flatt.jpg" ] https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FBookshelves%2FBiochemistry%2FFundamentals_of_Biochemistry_(Jakubowski_and_Flatt)%2F02%253A_Unit_II-_Bioenergetics_and_Metabolism%2F15%253A_Glucose_Glycogen_and_Their_Metabolic_Regulation%2F15.02%253A_Glycogenesis Expand/collapse global hierarchy • Home • Bookshelves • Biochemistry • Fundamentals of Biochemistry (Jakubowski and Flatt) • Fundamentals of Biochemistry Vol. II - Bioenergetics and Metabolism • 15: Glucose, Glycogen, and Their Metabolic Regulation • 15.2: Glycogenesis Expand/collapse global location \( \newcommand\) • • • • • • • • Search Fundamentals of Biochemistry Introduction The process of forming glycogen is called glycogenesis and it requires the activity of six enzymes as illustrated inFigure \(\PageIndex \nonumber \] UTP--glucose-1-phosphate uridylyltransferase (orUDP-Glucose Pyrophosphorylase) The formation of the UDP-glucose required for the synthesis of the main chain of glycogen is mediated by UTP-glucose-1-phosphate uridylyltransferase(preferred name), which is also called UDP-glucose pyrophosphorylase (GalU or UGPase; EC 2.7.7.9). UGPase catalyzes the r...

\( \newcommand\). Glycogen synthesis Glycogen synthesis begins with UDP-glucose phosphorylase, which combines the nucleotide uridine triphosphate (UTP) with glucose-1-phosphate to release pyrophosphate (PP i) and form UDP-glucose. The phosphoanhydride exchange reaction catalyzed by UDP-glucose phosphorylase is minimally exergonic. However, the pyrophosphate released is quickly hydrolyzed by inorganic pyrophosphatase, a ubiquitous cytosolic enzyme, in a highly exergonic reaction. This pyrophosphate hydrolysis is a mechanism utilized in many biosynthetic pathways to provide energy for otherwise endergonic reactions. In the next step, glycogen synthase attaches the UDP-glucose to the pre-existing glycogen chain with an α(1->4) linkage. It cannot join two individual glucoses together, only add to a pre-existing chain. This means that there must be some workaround for the first two glucoses: glycogenin is an enzyme that catalyzes the addition of UDP-glucose to itself, and can do so for up to seven UDP-glucose molecules, thus forming a short primer for glycogen synthase to work with. Furthermore, glycogen synthase can only add glucoses with an α(1->4) link. For branching to occur, a branching enzyme (specifically, amylo-(1,4->1,6)-transglycosylase is needed. This enzyme can transfer terminal chain segments to the 6-carbon hydroxyl of any glucose in a glycogen chain. However, the branches can only be added if there are at least 4 glucose residues between them, and if the originat...

[ "article:topic", "showtoc:no", "cssprint:dense", "autonumheader:yes2", "licenseversion:40", "glycogenesis", "glycogen synthase", "UDP-glucose pyrophosphorylase", "glycogenin", "glycogen branching enzyme", "authorname:jakubowski-flatt", "avatar@https://bio.libretexts.org/@api/deki/files/67680/Patty_Flatt.jpg" ] https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FBookshelves%2FBiochemistry%2FFundamentals_of_Biochemistry_(Jakubowski_and_Flatt)%2F02%253A_Unit_II-_Bioenergetics_and_Metabolism%2F15%253A_Glucose_Glycogen_and_Their_Metabolic_Regulation%2F15.02%253A_Glycogenesis Expand/collapse global hierarchy • Home • Bookshelves • Biochemistry • Fundamentals of Biochemistry (Jakubowski and Flatt) • Fundamentals of Biochemistry Vol. II - Bioenergetics and Metabolism • 15: Glucose, Glycogen, and Their Metabolic Regulation • 15.2: Glycogenesis Expand/collapse global location \( \newcommand\) • • • • • • • • Search Fundamentals of Biochemistry Introduction The process of forming glycogen is called glycogenesis and it requires the activity of six enzymes as illustrated inFigure \(\PageIndex \nonumber \] UTP--glucose-1-phosphate uridylyltransferase (orUDP-Glucose Pyrophosphorylase) The formation of the UDP-glucose required for the synthesis of the main chain of glycogen is mediated by UTP-glucose-1-phosphate uridylyltransferase(preferred name), which is also called UDP-glucose pyrophosphorylase (GalU or UGPase; EC 2.7.7.9). UGPase catalyzes the r...

\( \newcommand\). Glycogen synthesis Glycogen synthesis begins with UDP-glucose phosphorylase, which combines the nucleotide uridine triphosphate (UTP) with glucose-1-phosphate to release pyrophosphate (PP i) and form UDP-glucose. The phosphoanhydride exchange reaction catalyzed by UDP-glucose phosphorylase is minimally exergonic. However, the pyrophosphate released is quickly hydrolyzed by inorganic pyrophosphatase, a ubiquitous cytosolic enzyme, in a highly exergonic reaction. This pyrophosphate hydrolysis is a mechanism utilized in many biosynthetic pathways to provide energy for otherwise endergonic reactions. In the next step, glycogen synthase attaches the UDP-glucose to the pre-existing glycogen chain with an α(1->4) linkage. It cannot join two individual glucoses together, only add to a pre-existing chain. This means that there must be some workaround for the first two glucoses: glycogenin is an enzyme that catalyzes the addition of UDP-glucose to itself, and can do so for up to seven UDP-glucose molecules, thus forming a short primer for glycogen synthase to work with. Furthermore, glycogen synthase can only add glucoses with an α(1->4) link. For branching to occur, a branching enzyme (specifically, amylo-(1,4->1,6)-transglycosylase is needed. This enzyme can transfer terminal chain segments to the 6-carbon hydroxyl of any glucose in a glycogen chain. However, the branches can only be added if there are at least 4 glucose residues between them, and if the originat...

glycogenolysis, process by which When blood glucose levels fall, as during fasting, there is an increase in glucagon secretion from the The vast majority of glucose that is released from glycogen comes from Epinephrine, similar to glucagon, stimulates glycogenolysis in the liver, resulting in the raising of the level of blood glucose. However, that process is generally initiated by the Compare