Chemistry 451

Lecture #25: Gluconeogenesis

Read: pg. 452-459 AND article on Rotenone from Fairbanks Daily News Miner

HW: pg. 465 (Study Exercises 7,8,9 AND Problems 6,7) AND pg. 491 (Problem 10)

Objectives:
  1. Compounds that can be converted to oxaloacetate can be converted to glucose via gluconeogenesis.
  2. Conversion of pyruvate to glucose via gluconeogenesis requires enzymes that bypass the three exergonic steps of glycolysis: Pyruvate carboxylase and PEP carboxykinase (PEPCK) bypass pyruvate kinase; fructose-1,6-bisphosphatase (FBPase) bypasses phophofructokinase (PFK); and glucose-6-phosphatase bypasses hexokinase.
  3. Gluconeogenesis is regulated by changes in enzyme synthesis and by allosteric effectors including fructose-2,6-bisphosphate (F2,6P) and acetyl CoA.
  4. Acetyl CoA allosterically activates pyruvate carboxylase.
  5. F2,6P is a regulatory molecule that potently allosterically inhibits FBPase and activates PFK. (In this case potently means that a little F2,6P produces dramatic shifts in PFK and FBPase activity curves!)
  6. Synthesis of F2,6P (from F6P) depends on the phosphorylation state of the bifunctional enzyme phospohfructokinase-2/fructose bisphosphatase-2 (PFK-2/FBPase-2)

Follow the above links to see scanned figures from Lehninger, Principles of Biochemistry (Shown in class).