Glycogen Metabolism

Question 1

alpha - 1,4 - glycosidic linkage

Answer 1

joins one glucose to another

Question 2

glycogenin???

Answer 2

resp. for elongation

Question 3

branching of glycogen

Answer 3

amylo alpha 1,4 ->

alpha 1,6 transglycosidase

Question 4

GLYCOGENOLYSIS

Answer 4

enzyme: glycogen phosphorylase

removes monosaccharide glucose @ the non-reducing end

Question 5

DEBRANCHING ENZYME

Answer 5

Amylo 1,4 ->
1,4 transglycosidase

Alfa 1,6 glycosidase

Question 6

REGULATORY ENZYMES

Answer 6

GLYCOGEN SYNTHASE (Synthase)

GYCOGEN PHOSPHORYLASE (phosphorylase)

Question 7

GLYCOGEN SYNTHASE

D vs I

Answer 7

SYNTHASE D

• Phosphorylated
• • Inactive
• Allosteric enzyme
• ACTIVATOR = Glucose-6-P

SYNTHASE I

• Nonphosphorylated
• • Active
• Non allosteric

Question 8

GYCOGEN PHOSPHORYLASE

A vs B

Answer 8

PHOSPHORYLASE A

• Phosphorylated
• • Active
• Poorly allosteric (muscle)
• Allosteric (liver)
• inhibited by Glucose

PHOSPHORYLASE B

• Nonphosphorylated
• • Inactive
• Allosteric (muscle)
• Non allosteric (liver)
• Activated by AMP
• inhibited by Glucose-6-Phosphate & ATP

Question 9

increases glycemia

Answer 9

epinephrine

glucagon

Question 10

decreases glycemia

Answer 10

insulin

Question 11

Von Gierke’s

Answer 11

defect in G6Pase

Manifestation:

• Hepatomegaly
• Hypoglycemia
• Lactic acidemia
• Hyperlipidemia

Question 12

Pompe’s disease

Answer 12

defect in acid maltase (alpha - glucosidase)

Manifestation:
(infantile)
 - Severe muscle weakness
 - Enlargement of the heart, liver, and tongue 
(childhood)
 - Muscle weakness, especially respiratory muscles
(adult)
 - similar to chilhood

Question 13

GALACTOSEMIA (type 1, 2, and 3)

Answer 13

accumulation of galactose in the blood

Type 1

• UDPG-Galactose-1 Phosphate Uridyl Transferase
• Failure to thrive
• Jaundice unconjugated.
• Liver disease and cirrhosis
• Ascitis
• Cataracts
• Mental retardation

Type 2

• Galactokinase
• Only cataract

Type III

• UDP-galactose 4 Epimerase
• Benign form