Lecture #11 Coupling Pathways
Outline Some biochemistry The pentose pathway; –a central metabolic pathway producing pentoses and NADPH Co-factor coupling –NADPH, CO 2, GSH The stoichiometric matrix for PPP –Its null spaces Setting up a simulation model –Steady state Coupling to glycolysis Interpreting the results from simulation –Concentrations, fluxes, pools, ratios
BIOCHEMISTRY PRIMER
PPP: the oxidative and non-oxidative branches oxidative non-oxidative Coupling w/glycolysis
PPP: oxidative branch Glutathione buffers NADPH: GSH + NADP GSSG + NADPH
23DPG
THE PENTOSE PHOSPHATE PATHWAY Coupling Pathways
Reaction map Pentose Phosphate Pathway Compounds Elemental composition Reactions
PPP: S Matrix and Simulation Stoichiometric matrix Reaction map
Pathways
PPP: Phase Portraits In to R5P node Out off R5P nodePPP exit into glycolysis PPP exit into R5P synthesis
GLYCOLYSIS & the PENTOSE PHOSPHATE PATHWAY Coupling Pathways
Coupled pathways: Glycolysis and the pentose pathway
The integrated S matrix Coupling
Gly & PPP: Selected basis based on biochemical intuition
Kinetics Constants: PERCs
SIMULATING FLUXES AND CONCENTRATIONS Biochemistry
Glycolysis & PPP: Energy load 50% increase in this rate
Glycolysis & PPP: Phase Portraits v PYR v ATP v AMP
Glycolysis & PPP: Redox load Double this rate
Dynamic Simulation Increase in PPP fluxes Decrease in glycolysis fluxes Decrease in glycolytic conc Increase on PPP conc
SIMULATING POOLS Systems biology
Pools Pooling matrix Px Size and dynamics: PSv
SIMULATING RATIOS Physiology
Dynamic Simulation
New slide Add more explanation of the ratios
Summary The pentose pathway can be described in a similar way as glycolysis A simulation model can be formulated The two stoichiometric matrices describing the two pathways can be merged The coupling metabolites are G6P, F6P, GAP The structure of the null space for glycolysis alone and the coupled pathways is similar Pools and ratios can be formed as before Simulation to 50% increase in rate of utilization of ATP is similar to that of glycolysis alone Systems biology shows up –Definition of pathways, definition of pools