1. Chapter 16.6 & 16.7 Enzymes & Enzyme Actions SWBAT: Describe how enzymes function as catalysts and give their names Describe the role of an enzyme in an enzyme-catalyzed reaction

2. Enzymes are…. biological catalyst which speed up Rx by lowering the Activation Energy mostly proteins, some RNA not used up in the reaction What is an enzyme?

3. Enzymes are…. globular proteins small, compact, stable with a unique 3-D shape Have a special pocket called active site

4. The Active Site Is an area where the enzyme binds the substrate and catalyzes the reaction fits only a few types of substrates Active Site Substrate

5. Enzyme Rx Formation of the enzyme substrate (ES) complex weakens covalent bonds in the substrate E + S ES EP E + P  E = enzyme  S = substrate  P = product How enzymes work?

6. “Lock and Key” Theory Active site = lock; substrate = key 1.enzyme binds one specific substrate to form ES complex 2.Substrate is converted to product 3.Product leaves active site 4.Enzyme binds next substrate

7. “Induced Fit” Model Enzyme changes shape when binding substrate Enzyme serves a range of similar substrates

8. Enzyme Naming Most end with –ase Reflect substrate or reaction types: amylase, oxidase Older enzyme names often end in –in Ex: pepsin, rennin, trypsin

9. Enzyme Rx classifications Anabolic reactions  Synthesis of complex substances from simple building blocks (growth, repair)  Amino Acids  Polypeptides  Proteins Catabolic reactions  Breakdown of complex substance into building blocks (digestion)  Proteins → Polypeptides → Aminoacids

10. Classification of Enzyme Reactions Oxidoreductoases: oxidation/reduction Rx Transferases: transfer functional groups (Kinase: transfers phosphates) Hydrolases: breaking molecules in presence of H2O (Carbohydrases, Proteases, Lipases) Lyases: (Add/Remove groups with double bonds Isomerases: rearrange to form isomers (cis/trans) Ligases: connect molecules using ATP (DNA strands in replication)

11. Chapter 16.8 Factors Affecting Enzyme Activity SWBAT: Describe the effect of temperature, pH, concentration of substrate and inhibitors on enzyme activity

12. Factors Affecting Enzyme Reaction Rates Temperature pH Concentrations of substrates (body) Concentration of enzyme (body) Presence of inhibitors (body)

13. Temperature Too high: denaturation, loss of 3D (often reversible if not too high!) Too low: slow Rx rates Optimum Temperature depends on species: Mammals: 37°C Thermophile bacteria: 80-90 o C (thermal springs) Arctic flies: 5 o C temperature

14. pH Optimum pH depends on natural enzyme environment Too high/low denatures enzyme and/or affects electrostatic attraction at active site Tissue and blood enzymes: pH 7.4 Stomach enzyme (pepsin) : pH 2.0 Pancreatic enzyme (trypsin): pH 8.0

15. pH (cont.)

16. Substrate & Enzyme Concentrations Generally: increasing substrate concentration increases Rx rate

17. Vmax All enzyme molecules work at max speed, adding more substrate does not increase rate Only increase in enzyme concentration further increases rates!

18. Animation Animation comparing  Enzymes  Substrates  Inhibitors  Temperature  pH Link to animation

19. Enzyme Inhibitor

20. Competitive Inhibition

21. Non-Competitive Inhibition

22. Enzyme Cofactors Complex enzymes: require cofactors - metal ions - to function Metal ions: Cu2+, Fe2+/3+, Zn2+, Mg2+, Mn2+, Ni2+ - obtained from food Enzymes of the electron transport chain in mitochondrial membranes: oxidorecutases Enzyme without the cofactor: apoenzyme Enzyme with cofactor bound: holoenzyme

23. Cofactor function

24. Vitamins and Coenzymes Vitamins are organic molecules that work together with enzymes Vitamins are essential: have to be taken up with diet: B, C, Biotin, folic acid Coenzymes have the same function, but are produced by the body: NADH, FADH, ATP (Kinases)

25. Special food proteins A. Gluten The “glue-protein” Protein found in wheat, barley, rye makes dough elastic! Oats, rice, corn, quinoa are gluten free but often contaminated! About 1% of the population is allergic to gluten or has celiac disease Symptoms: include bloating, abdominal pain, diarrhea, muscle, bone or joint pain Correlation of thyroid problems and gluten allergies….

26. B. Casein Main protein in mammalian milk, highest in cow’s milk (80%) Adults can be allergic to casein (just like with lactose) Animal experiments show a correlation of high casein intake and cancer development Population studies from China (China Study) and Norway (WWII) correlate significant lower rates of breast and prostate cancer in dairy free populations….

27. C. Prions – misfolded proteins Invalidates current pathogen definitions as being only bacteria or viruses Misfolded “diseased” preptides induce wrong folding in normal proteins: seeded induction Ingestion from diseased meats Cannot be cleared out of cells, but accumulate and form amyloid aggregates in brain and nervous tissue (lots of beta pleated sheets)

28. Protein Diseases Mad Cow Disease (Creutzfeldt-Jacob D): food chain infection form diseased animals One form of Alzheimer’s Huntingtons Parkinsons