Term
| What is the first step of Glycogenolysis? |
|
Definition
Glyogen -> Glucose 1-Phosphate
via Phosphorylase |
|
|
Term
| What is the second step of glucogenolysis? |
|
Definition
Glucose 1-phosphate -> Glucose 6-phosphate
via phosphoglucomutase |
|
|
Term
| What is the final step of glycogenolysis in the liver? |
|
Definition
Glucose 6-phosphate -> Glucose
via Glucose 6-phosphatase |
|
|
Term
| What is the final step of glycogenolysis in the muscles? |
|
Definition
| Anaerobic metabolism of glucose. Yields 2 lactate and ATP |
|
|
Term
| What kind of bonds can phosphorylase cleave? |
|
Definition
|
|
Term
| How are branched chains dealt with in glycogenolysis? How does this work? |
|
Definition
With the debranching enzyme
The debranching enzyme has two steps
1) 1-4:1-4 transferase activity (leaving only the alpha 1-6 bond)
2) alpha 1-6 glucosidase activity (cleaving leftover alpha 1-6 bond) |
|
|
Term
| What is the fist step of Glycogenesis? |
|
Definition
Glucose -> Glucose 6-phosphate
via Glucokinase (liver) Hexokinase (muscle) |
|
|
Term
| What is the second step of Glycogenesis? |
|
Definition
Glucose 6-phosphate -> Glucose 1-phosphate
via Phosphoglucomutase |
|
|
Term
| What is the third step of Glycogenesis? |
|
Definition
Glucose 1-phosphate -> UDP-glucose
via UDP-glucose pyrophosphorylase |
|
|
Term
| What is the final step of Glycogenesis? |
|
Definition
UDP-glucose -> Glycogen
via Glycogen Synthase |
|
|
Term
| What kind of bonds can Glycogen synthase form? |
|
Definition
|
|
Term
| How are branched chains synthesized in glycogen? What enzyme is responsible? |
|
Definition
Branching enzyme
has a 1,4:1,6 transferase activity that allows for the necessary branching to occur |
|
|
Term
| What is the presentation and deficient enzyme of a Type I Glycogen Storage Disease (Von Gierke) |
|
Definition
Glucose-6 phosphatase
Presentation: sever hypoglycemia, lactic acidosis, hepatomegaly, hyperlipidemia, hyperuricemia, short stature, doll-like facies, protruding abdomen, and emaciated extremities |
|
|
Term
| What is the deficient enzyme and clinical presentation of a patient with a type II glycogen storage disease (Pompe) |
|
Definition
Lysosomal alpha1,4-glucosidase
presentation: cardiomegaly, muscle weakness
prognosis: death by two years |
|
|
Term
| What is the deficient enzyme and clinical presentation of a patient with a type V glycogen storage disease (McArdle)? |
|
Definition
Muscle glycogen phosphorylase
presentation: muscle cramps and weakness on strenous exercise, myoglobinuria |
|
|
