1. Chapter 15
Design of metabolism

3. G, Free Energy, recall:

4. For biochemical reactions, we define a different standard state for the concentration of H+
standard state for [H+] = 10-7 M, pH = 7.0
this modified standard state is given the symbol G°’

5. ATP
the experimental value of K’eq = 2.23 x 105

6. ATP-Why?
repulsion
resonance
BUT,it’s kinetically stable

7. Other “high energy compounds

8. "High energy" substance: a thermodynamically unstable substance whose hydrolysis or decomposition can be easily coupled to an unfavorable reaction. The arbitrary cut-off is ~-10kJ/mol. There is no such thing as a "high energy bond" per se.

9. Coupled Reactions
Free energies are additive; favorable rxns can drive unfavorable;e.g.sequential coupling

10. Delta Thigh Project II
Also see

11. Sequential coupling

12. Simultaneous coupling
Example:Glucose to glucose-6-phosphate

13. Example: calculate G°’ for this reaction involving phosphoenolpyruvate (PEP) and decide whether or not it is spontaneous
use the following information from Table 14.1

14. Under aerobic conditions, glucose is oxidized to carbon dioxide and water
the efficiency of the energy conservation under aerobic conditions is approximately 34%
Metabolism concerns how you get from here to there!!

15. Metabolic strategies-Oxidation(burning of carbon containing compounds)

16. Substrate level phosphorylations

17. Ion gradients

18. Overall Process

19. Recurring Motifs in Metabolism “Activated” electron and functional group carriers

20. Electron Carriers:
NAD+

21. Electron Carriers:
FAD

22. Typical Oxidation Reactions

23. “Carbon” carriers

24. Chemical Reaction “themes” in metabolism

25. Chemical Reaction “themes” in metabolism: Patterns

26. Factors Affecting Metabolic Rate
Metabolism operates at a steady state.
Metabolites flow through the steady state

27. Factors Affecting Metabolic Rate

28. Factors Affecting Metabolic Rate
Metabolites flow through the steady state
ATP

29. Factors Affecting Metabolic Rate

30. Factors Affecting Metabolic Rate

31. Factors Affecting Metabolic Flow or flux through pathways
Amounts of enzymes
Catalytic activity of enzymes
Availability of substrates

32. ATP Balance affects many metabolic pathways

33. ATP Balance affects many metabolic pathways

34. CONTROL OF METABOLIC FLUX, J
rate determining
step S A B J P
e.g. glucose
pyruvate

35. CONTROL OF METABOLIC FLUX, J
e.g. Substrate Cycling:
See glycolysis (F-6-P to F1,6-BP)