2. Metabolic Biochemistry Lecture 9 August 19, 2005 Oxidative phosphorylation Other Pathways of Carbohydrate Metabolism Photosynthesis

3. Import of NADH into mitochondria

4. LNC 19-27 Example of a shuttle for oxidizing NADH from the cytosol

5. LNC 19-26

6. Getting ATP and ADP in and out of mitochondria

7. LNC 19-25 Biological work

8. for NADH: P/O ratio ~ 2.5 for succinate: P/O ratio ~ 1.5

9. S UBSTRATE LEVEL PHOSPHORYLATION GAP + P i + NAD + NADH + 1,3 bisphosphoglycerate 1,3 bisphosphoglycerate + ADP ATP + 3 phosphoglycerate 1 ATP produced per NAD+ reduced per GAP used up per 3-PG produced There is a precise stoichiometry

10. OXIDATIVE PHOSPHORYLATION NADH + 1/2 O 2 + H + NAD + + H 2 O ~ 3 ADP + ~ 3 Pi~ 3ATP <3 ATP produced per NADH oxidized per H 2 O produced per 1/2 O 2 consumed (P/O ratio ~ 2.5) There is no precise stoichiometry, because protons can find other paths to return to the matrix

11. When succinate is the substrate, the P/O ratio is ~1.5, because only two pumps are used (only 6 protons are pumped per succinate)

12. Regulation of OXPHOS:

13. Mitochondria contain DNA (~16.5 kb) mtDNA encodes 2 rRNAs 22 tRNAs 13 proteins (in animals) mtDNA can have mutations causing mitochondrial diseases

14. GLUCONEOGENESIS LNC Chapter 14, Section 14.4 PENTOSE PHOSPHATE SHUNT LNC Chapter 14, Section 14.5

15. LNC Fig. 14-15

16. Phosphoenolpyruvate PEP fructose-1,6 bisphosphate phosphatase pyruvate first bypass third bypass second bypass LNC Fig. 14-16

17. BIOTIN is a co-factor utilized for CARBOXYLATION REACTIONS THIAMINE PYROPHOSPHATE (TPP) is a co-factor utilized for DECARBOXYLATION REACTIONS LNC Fig. 14-18

18. in muscle in liver first bypass LNC Fig. 14-19

19. Chapter 15, Section 15.3 (pp.575) Coordinated Regulation of Glycolysis and Gluconeogenesis emphasis on regulation of phosphofructokinase-1 and fructose 1,6 bisphosphatase

20. LNC Fig. 14-16

21. Phosphofructokinase-1 4 identical subunits (two shown) 1 active site per subunit 1 site for allosteric regulator (ADP/ATP) LNC Fig. 15.18

22. Phosphofructokinase-1 PFK-1 Fructose bis-phosphatase FBPase LNC Fig. 15-22

23. LNC Fig. 15-23

24. THE PENTOSE PHOSPHATE PATHWAY Section 14.5 two significant products:ribose-phosphate NADPH

25. End of Lecture 9 August 19, 2005