Glycogen Metabolism

Question 1

Glycogen

Answer 1

blood glucose is requirement for human life. Glycogen is stroed in the form of glucose. Liver and muscles (10%) are the main storage place.

Question 2

structure

Answer 2

It is a branched chain homopolysaccharide made from a-d-glucose. Primary glycosidic bond is an a-(1-3) linkage. Average 8-10 glucosyl residues there is a branch which is an a(1-6) linkage. Lysosomal enzymes continusouly degrade glycogen, unknown reasons but can cause storage disease.

Question 3

Liver Glycogen

Answer 3

saturated in well fed and depleted during fasting (between meals)

Question 4

Muscle Glycogen

Answer 4

not depleted during short fasting states but may be during long inteense fasting (think days) Depleated during strenuous exercise and replenished after. (Short but INTENESE workout)

Question 5

Synthesis/Branching

Answer 5

Increases solubility, rate & degredation, protects from destruction. Branch points are a(1-6) glycosidic bonds.

Question 6

Glycosyl, 4-6, Transferase

Answer 6

Branching enzyme required to create the 1-6 point.

Question 7

Glycogen synthase

Answer 7

elongation enzyme for glycogen a(1-4) links

Question 8

Amylo-(1-4,1-6) transglycosylase

Answer 8

is the branching enzyme which forms glycogen

Question 9

When is a branch created?

Answer 9

A transfer of a terminal chain segment consisting of 7 residues. This must come from a chain of at least 11 residues and must be 4 apart from the other branch point.

Question 10

Glycogen Phosphorylase

Answer 10

cleaves the primary alpha 1,4 glycosidic bonds

Question 11

Debranching enzymes

Answer 11

Alpha a 4 transglycosylase (glycosyl transferase)

Amylo alpha 1-6 glucosidase

Question 12

Alpha a 4 transglycosylase

Answer 12

Transfers the last3-4 resdues (limit) of a branched chain to the primary chain

Question 13

Amylo-alpha-1,6-glucosidase

Answer 13

cleaves the 1-6 linkage of the final glucose on a branch point via hydrolysis releaseing free glucose.

Question 14

Von Girke

Answer 14

glucose 6 phosphate defect in the liver and kidney. Increase amount of normal structure. Enlarged liver, failure to thrive, severe hypoglycemia, hyperlidemia, hyperuricemia, ketosis

Question 15

Pempe Disease

Answer 15

a 1,4 glucosidase lysosomal defect affects all organs. massive increase in glycogen levels but normal structures. Cariorespiratory failure death before age 2

Question 16

Cori Disease

Answer 16

Amylo 1,6 glucosidase (debranch) defect in muscle and liver. Increased amount of glycogen but shorter outer branches. Milder than von girke

Question 17

Andersen disease

Answer 17

Branching enzyme 1,4 and 1,6 defect in liver and spleen. Normal amount of glycogen long outer branches. Cirrhosis of lvier death before 2

Question 18

McArdles Disease

Answer 18

Phosphorylase defect in muscles. Moderate increase in glycogen with normal structure. No strenous exercise due to cramping. Otherwise normal