BIOL 112 Lecture Notes - Lecture 10: Metabolic Pathway, Glycolysis, Endergonic Reaction
15 Jun 2018
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BIOL 112: GLYCOLYSIS
Regulation of Metabolic Pathways: end-product (inhibiting the first enzyme in the pathway) or
feedback inhibition regulates the whole pathway (5 distinct chemical reactions catalyzed by
there own unique enzymes) PICTURE
- Multiple feedback controls allow cells to adjust the ratio of different compounds (e.g.
AA) which are precisely regulated (red line is where the end product regulates an
enzyme)
Enzyme Regulation:
Competitive – binds directly to the active site; making the substrates unable to bind the
molecules
- 1 000 000 molecules to break down the enzyme, you need more competitor molecules
rather than substrate molecules
Allosteric other site – binding makes a conformation change; the shape of the enzyme
changes, binds to a different site on the enzyme
- Much more efficient than competitive because it comes down to the number of
regulatory molecules, e.g. allosteric only needs 1 competitor
Cooperative Allosteric Transition: occurs with 2 or more subunits
- Second subunit can be shut down way faster because both subunits are attached, and
both effected by the same inhibitor
- “igoid “ cure due to cooperatie trasitio, giig a steep cure here the ezye
gets turned off quickly, its very hard for the first inhibitor molecule to bind, but by the
2nd inhibitor it can rapidly bind, & the speed of binding increases the more inhibitor
olecules are preset akig “ cure
The first step in a metabolic pathway is nearly always a multi-subunit enzyme negatively
regulated by cooperative allostery
Glycolysis & Redox Reactions: The Oxidation of Sugars
C6H12O6 + 6O2 → 6CO2 + 6H2O + free energy (ATP)
- Half of the energy from glucose is collected in ATP (endergonic)
- Complete oxidation of glucose is -686 kcal/mol (exergonic)
Energy for Life: Sun → Photosynthesis → Stored Chemical E → Glycolysis → Anaerobic
(Fermentation) 29 ATP no O2 / Aerobic (Cell Respiration) 2 ATP O2
Redox Reactions: The Transfer of Electrons
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BIOL 112 Full Course Notes
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Document Summary
Regulation of metabolic pathways: end-product (inhibiting the first enzyme in the pathway) or feedback inhibition regulates the whole pathway (5 distinct chemical reactions catalyzed by there own unique enzymes) picture. Multiple feedback controls allow cells to adjust the ratio of different compounds (e. g. aa) which are precisely regulated (red line is where the end product regulates an enzyme) Competitive binds directly to the active site; making the substrates unable to bind the molecules. 1 000 000 molecules to break down the enzyme, you need more competitor molecules rather than substrate molecules. Allosteric (cid:862)other site(cid:863) binding makes a conformation change; the shape of the enzyme changes, binds to a different site on the enzyme. Much more efficient than competitive because it comes down to the number of regulatory molecules, e. g. allosteric only needs 1 competitor. Cooperative allosteric transition: occurs with 2 or more subunits.
