Just enough biochemistry to be dangerous??. http://www.detoxi-pad.com/. Just enough biochemistry to be dangerous??. http://www.tahitiannoni.com/united_states/english/retail/store/research/index.html. Chapter 15. Design of metabolism. http://www.chem.uwec.edu/Chem454_S08/MetabolicchartBig.pdf.
Just enough biochemistry to be dangerous?? • http://www.detoxi-pad.com/
Just enough biochemistry to be dangerous?? http://www.tahitiannoni.com/united_states/english/retail/store/research/index.html
Chapter 15 Design of metabolism
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°’
ATP • the experimental value of K’eq = 2.23 x 105
ATP-Why? repulsion resonance BUT,it’s kinetically stable
"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.
Coupled Reactions Free energies are additive; favorable rxns can drive unfavorable;e.g.sequential coupling
Simultaneous coupling Example:Glucose to glucose-6-phosphate
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
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!!
Recurring Motifs in Metabolism “Activated” electron and functional group carriers
Electron Carriers: H:- NAD+
Factors Affecting Metabolic Rate • Metabolism operates at a steady state. • Metabolites flow through the steady state
Factors Affecting Metabolic Rate • Metabolites flow through the steady state ATP
Factors Affecting Metabolic Flow or flux through pathways • Amounts of enzymes • Catalytic activity of enzymes • Availability of substrates
J J S A B CONTROL OF METABOLIC FLUX, J rate determining step P e.g. glucose pyruvate
CONTROL OF METABOLIC FLUX, J e.g. Substrate Cycling: See glycolysis (F-6-P to F1,6-BP)