Gluconeogenesis practice problem key

Gluconeogenesis practice problem key - BMB...

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Unformatted text preview: BMB 401Gluconeogenesis Practice problems Page 1 1) Please state the three glycolytic enzymes that catalyze irreversible reactions. and indicate the gluconeogenic enzyme or enzymes that are used to go around each roadblock. a. Glycogenic enzyme__Hexokinase_________________ b. Gluconeogenic enzyme(s)___Glucose 6 ­phosphatase_______ ____________________________________________________________________________________ a. Glycogenic enzyme__Phosphofructokinase ____________________________ b. Gluconeogenic enzyme(s)____ Fructose 1,6 ­bisphosphatase _______ ____________________________________________________________________________________ a. Glycogenic enzyme_________Pyruvate kinase__________________________________ b. Gluconeogenic enzyme(s)__ o Pyruvate carboxylase, (carboxylates pyruvate to make OAA) __________ o Malate Dehydrogenase (The mitochondrial isozyme reduces OAA to form malate and then the cytoplasmic isozyme catalyzes the reverse reaction) o Phosphoenolpyruvate carboxykinase (decarboxylates and phosphorylates OAA to form phosphoenolpyruvate) 2) During gluconeogenesis oxaloacetate must be changed to malate in what intracellular compartment? (cytosol/mitochondrial matrix) 3) Why must oxaloacetate be changed to malate in this compartment?___________ _There is no transporter for OAA in the inner mitochondrial membrane to transport OAA from one compartment to the other___________________________ 4) How is this pathway regulated? Please state each enzyme and the metabolite that increases or decreases the activity of each enzyme__________________________ o G6Phosphatase: Information on the regulation of this enzyme is not required in this class. o Fructose 1,6 ­bisphosphatase: Positive: Citrate, Negative: F2, 6 ­BP and AMP o Phosphoenolpyruvate carboxykinase: Negative: ADP o Pyruvate carboxylase: Positive: Acetyl CoA, Negative: ADP 5) Please state the meaning of “reciprocal regulation” This means that the same signal that inhibits one pathway will activate the opposite pathway. For instance F2, 6 ­BP deactivates gluconeogenesis and activates glycolysis. This reduces the occurrence of futile cycles of concurrent anabolism & catabolism. ...
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This note was uploaded on 10/18/2011 for the course BMB 401 taught by Professor Kaguni during the Fall '08 term at Michigan State University.

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