1. Ch. 6 Metabolism Diagrams

2. Figure 8.UN01 Enzyme 1 Enzyme 2 Enzyme 3 Reaction 1 Reaction 2Reaction 3 ProductStarting molecule A B C D

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4. Figure 8.3 (a) First law of thermodynamics (b) Second law of thermodynamics Chemical energy Heat

5. Figure 8.6 (a) Exergonic reaction: energy released, spontaneous (b) Endergonic reaction: energy required, nonspontaneous Reactants Energy Products Progress of the reaction Amount of energy released (  G  0) Reactants Energy Products Amount of energy required (  G  0) Progress of the reaction Free energy

6. Figure 8.8 (a) The structure of ATP Phosphate groups Adenine Ribose Adenosine triphosphate (ATP) Energy Inorganic phosphate Adenosine diphosphate (ADP) (b) The hydrolysis of ATP

7. Figure 8.9 Glutamic acid Ammonia Glutamine (b) Conversion reaction coupled with ATP hydrolysis Glutamic acid conversion to glutamine (a) (c) Free-energy change for coupled reaction Glutamic acid Glutamine Phosphorylated intermediate Glu NH 3 NH 2 Glu  G Glu = +3.4 kcal/mol ATP ADP NH 3 Glu P P i ADP Glu NH 2  G Glu = +3.4 kcal/mol Glu NH 3 NH 2 ATP  G ATP =  7.3 kcal/mol  G Glu = +3.4 kcal/mol +  G ATP =  7.3 kcal/mol Net  G =  3.9 kcal/mol 1 2

8. Figure 8.10 Transport protein Solute ATP P P i ADP P i ADP ATP Solute transported Vesicle Cytoskeletal track Motor proteinProtein and vesicle moved (b) Mechanical work: ATP binds noncovalently to motor proteins and then is hydrolyzed. (a) Transport work: ATP phosphorylates transport proteins.

9. Figure 8.11 Energy from catabolism (exergonic, energy-releasing processes) Energy for cellular work (endergonic, energy-consuming processes) ATP ADPP i H2OH2O

10. Figure 8.UN02 Sucrase Sucrose (C 12 H 22 O 11 ) Glucose (C 6 H 12 O 6 ) Fructose (C 6 H 12 O 6 )

11. Figure 8.12 Transition state Reactants Products Progress of the reaction Free energy EAEA  G  O A B C D A B C D A B C D

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13. Figure 8.13 Course of reaction without enzyme E A without enzyme E A with enzyme is lower Course of reaction with enzyme Reactants Products  G is unaffected by enzyme Progress of the reaction Free energy

14. Figure 8.14 Substrate Active site Enzyme Enzyme-substrate complex (a) (b)

15. Figure 8.15-3 Substrates Substrates enter active site. Enzyme-substrate complex Enzyme Products Substrates are held in active site by weak interactions. Active site can lower E A and speed up a reaction. Active site is available for two new substrate molecules. Products are released. Substrates are converted to products. 1 2 3 4 5 6

16. Figure 8.16 Optimal temperature for typical human enzyme (37°C) Optimal temperature for enzyme of thermophilic (heat-tolerant) bacteria (77°C) Temperature (°C) (a) Optimal temperature for two enzymes Rate of reaction 120 100 80 60 40200 0 12 3 4 5 6 78910 pH (b) Optimal pH for two enzymes Optimal pH for pepsin (stomach enzyme) Optimal pH for trypsin (intestinal enzyme)

17. Figure 8.17 (a) Normal binding(b) Competitive inhibition (c) Noncompetitive inhibition Substrate Active site Enzyme Competitive inhibitor Noncompetitive inhibitor

18. Figure 8.19 Regulatory site (one of four) (a) Allosteric activators and inhibitors Allosteric enzyme with four subunits Active site (one of four) Active form Activator Stabilized active form Oscillation Non- functional active site Inactive form Inhibitor Stabilized inactive form Inactive form Substrate Stabilized active form (b) Cooperativity: another type of allosteric activation

19. Figure 8.20 Caspase 1 Active site Substrate SH Known active form Active form can bind substrate Allosteric binding site Allosteric inhibitor Hypothesis: allosteric inhibitor locks enzyme in inactive form Caspase 1 Active formAllosterically inhibited form Inhibitor Inactive form EXPERIMENT RESULTS Known inactive form

20. Figure 8.21 Active site available Isoleucine used up by cell Feedback inhibition Active site of enzyme 1 is no longer able to catalyze the conversion of threonine to intermediate A; pathway is switched off. Isoleucine binds to allosteric site. Initial substrate (threonine) Threonine in active site Enzyme 1 (threonine deaminase) Intermediate A Intermediate B Intermediate C Intermediate D Enzyme 2 Enzyme 3 Enzyme 4 Enzyme 5 End product (isoleucine)