1. Metabolism

2. Enzymes: review

3. Anabolism vs Catabolism

5. What is necessary for a chemical reaction to begin?

6. Reactant(s) must come together in the right orientation With enough energy So ho do enzymes catalyze this process?

8. Lowers activation energy Template for proper orientation of substrates As active site “holds” substrate – can stress/strain the substrate, breaking bonds More conducive microenvrionments – ie altering pH

13. Enzyme specificity What contributes to it?

14. Complementary fit

15. Lock and Key Model

16. Induced Fit Model (replaces lock and key) Enzymes = globular proteins Shape shifters – subtle Active site is not rigid Can fit more snugly around substrate

17. Catalysis Saturation – limiting factor = max enzymatic rate

18. Enzyme efficiency Determined by environmental factors Optimal conditions

19. Cofactors Nonprotein helpers Zinc, iron, copper Vary in how they bind to enzyme Perform a critical function in catalysis

20. coenzymes Organic cofactors Most vitamins

21. Other factors influencing reaction rate… inhibitors Reversibility

22. Competitive inhibition

23. Noncompetitive inhibition

24. examples Sarin: nerve gas DDT and parathion antibiotics

25. Regulation Selective inhibition Cells control when and where enzymes are active control the building of the protein Control the protein once its built

26. Allosteric regulation Protein function at one site is affected by the binding of a regulatory molecule to a separate site Can inhibit or stimulate