Glycogen Metabolism Flashcards
is a readily mobilized storage form of glucose. It is a large, branched chain of glucose molecules that can be broken down to release glucose for energy.
Glycogen
The majority of glucose units are connected by?
α-1,4-glycosidic bonds
The majority of glucose units are connected by α-1,4-glycosidic bonds, with branches occurring roughly every tenth unit through?
α-1,6-glycosidic bonds
is not as reduced as fatty acids and is not as energy-rich
Glycogen
major part sites of glycogenolysis
Liver and muscle
all the enzymes concerned with glycogenolysis are present in cytosol.
Cytosol
this enzyme will decide the rate of glycogenolysis.
Glycogen phosphorylase
Resting muscle contains how many grams of glycogen?
400g
is the formation of glycogen when glucose supplies exceed the cellular need for ATP synthesis
glycogenesis
is the source of all the glucosyl residues that are added to the growing glycogen molecule
UDP-glucose
4 Main Step in Glycogen Synthesis:
- Attaching uridine diphosphate (UDP) to glucose
- Attaching glucose to glycogenin (serves as primer)
- Adding more glucose
- Adding more branches
Glycogen synthase cannot start glycogen synthesis without a?
primer
a protein acting as a primer, auto glycosylated to form a short glucosyl chain, enabling glycogen synthesis.
Glycogenin
Glycogen synthase elongates?
glycogen chains
Branches in glycogen are formed by the branching enzyme, which transfers chains of glucosyl residues from the nonreducing end of the glycogen chain to a non-terminal glucosyl residue, creating a?
highly branched structure of glycogen
Glycogen Breakdown, also known as?
glycogenolysis
is a metabolic process initiated by the body when there is a demand for glucose that typically occurs during fasting periods or intense physical activity such as exercise
glycogenolysis
Known as the central player that catalyzes the phosphorolytic cleavage of glycogen to release glucose 1-phosphate it is a key intermediate in glucose metabolism.
Glycogen Phosphorylase
Essential enzyme that relies on pyridoxal phosphate (PLP) that is a derivative of Vitamin B6 to cleave glycogen.
Phosphorylase
can be readily converted into glucose 9-phosphate. an essential metabolite in cellular energy.
Glucose 1-phosphate
moves a block of three glycosyl residues from one outer branch to the other, exposing a glucose residue linked by an α-1,6-glycosidic bond.
transferase
hydrolyzes the bond, freeing a glucose molecule.
α-1,6-glucosidase or debranching enzyme
This free glucose is then phosphorylated by?, converting the branched structure into a linear one, which can be further cleaved by phosphorylase
hexokinase
