1 SURVEY OF BIOCHEMISTRY More on Glycogen Control Citric Acid Cycle

2 Agenda Recap regulation of glycogen metabolism What we have covered –Glycolysis –Glycogen breakdown –Glycogen synthesis –Gluconeogenesis Citric Acid Cycle overview

3 Ways to Regulate Glycogen Metabolism Allosteric Control Covalent Modifications –Phosphorylation –Dephosphorylation Hormonal Control –Insulin –Glucagon Review these for Exam #3 and the Final Exam

4 Covalent Modifications Glycogen Phosphorylase Glycogen phosphorylase participates in glycogen breakdown Glucagon stimulates this process cAMP activates PKA

5 Hormonal Control InsulinGlucagon Secreted in the beta cells Secreted in the alpha cells 51 aa peptide hormone29 aa peptide hormone Increases glycogen synthesisIncreases glycogen breakdown Decrease blood glucoseIncreases blood glucose Increases cellular uptake of glucose to make glycogen

6 Hormonal Control

7 Amino Acid Entry Into TCA Cycle Notice how there are different pathways for aa’s to enter into the TCA cycle.

8 Citric Acid Cycle Overview Alternative Names for Cycle: Kreb’s Cycle Tricarboxylic Acid (TCA) Cycle

9 Fates of Pyruvate Focus on pyruvate entry into the TCA cycle. Pyruvate Acetyl-CoA Amino Acids Fatty Acids Citric Acid Cycle Key Products CO 2 NADH FADH 2 GTP