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Unformatted text preview: Quiz #11 1 (4 pts). Choose one of the allosterically regulated enzymes in gluconeogenesis (pyruvate carboxylase, phosphoenol pyruvate carboxykinase, or fructose 1,6-bisphosphatase). For that enzyme: Name one allosteric regulator State whether that regulator is an activator or an inhibitor Explain the biochemical logic behind that regulation step. Pyruvate carboxylase ADP/inhibits Acetyl CoA stimulates Phosphoenol pyruvate ADP/inhibits carboxykinase AMP/inhibits Fructose 1,6-bisphosphatase Citrate/activates AMP/inhibits Fructose 2,6 Bisphosphate/inhibits ADP and AMP are inhibitors because energy charge is low Acetyl coA stimulates to make more OAA Citrate high levels indicate high OAA F2,6BP is formed in response to insulin- favors glycolysis 2 (3 pts). Immediately after a meal, insulin levels rise. Will glycogen synthesis in the liver increase or decrease? Increase Describe how insulin stimulation of liver cells affect glycogen phosphorylase. It inactivates it. Insulin stimulation activates protein phosphatase 1 (PP1), which removes a phosphate from glycogen phosphorylase converting it to the b (inactive) form. 3. (3 pts) Suppose the kinase domain is active in the dual functional enzyme phosphofructokinase-2/fructose bisphosphatase-2 (PKF- 2/FBPase-2). What will be the effect on gluconeogenesis? Why? Decrease because PFK2 will catalyze the synthesis of F2,6BP, which will inhibit FBPase-1. ...
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This note was uploaded on 05/06/2010 for the course BIOC 460 taught by Professor Ziegler during the Spring '07 term at University of Arizona- Tucson.
- Spring '07