C-Notes: Enzymes

1. C-Notes: Enzymes Stnd: BI.1b 9/9/13 SWBAT recognize that enzymes are proteins that catalyze biochemical reactions in cells. Objective:

2. Are PROTEINSthat acts as biological catalyst to speed up chemical reaction in living cells. (“catalyst/catalyze/catalase”  the actionof enzymes to speed up a chemical reaction in living cells) What are Enzymes? “Helper” protein molecules

3. Flow of energy through life • Life is built on chemical reactions

4. enzyme enzyme + + • Building molecules 2. Breaking down molecules How do Enzymes function (work) in a cell ? • They do almostALLthe work within a cell. • **It decreasedactivation energy and increase reaction rate. ** We can’t live without enzymes!

5. + enzyme enzyme enzyme enzyme + Examples • synthesis • digestion

6. How does the structure of an enzyme affect its function? • Enzymes are SPECIFIC! • Each enzyme has a SPECIFIC “SHAPE” that only allows for a certain “reactant” to bind to it. (needs to be the RIGHT SHAPE for the job) 2. Enzymes are REUSABLE! • B/C they are not used up or changed by the reaction when breaking down a substrate and can perform the same action over and over very quickly. The specific reactant that enzymes binds to is called SUBSTRATE (food & waste) . Substrates binds to specific places on an enzyme called“active sites” Ex: Protease (Enzymes) only breaks down (binds to) proteins (substrate)to form amino acids “product” Ex: “protease” + “protein”  Amino Acids (Enzyme) (substrate) (product) You can recognize enzymes b/c it ends in –ase Enzymes are named for the reaction the help! Ex: Lactase  breakdown lactose in milk Protease  breakdown proteins Lipase  breakdown lipids (Enzymes) (Macromolecules)

7. Substrate – the substance that the enzyme works on e.g. Lipase the substrate is lipids Product – the substance that is made by the reaction e.g. Breakdown of Lipids by Lipase the product is __________________ Fatty acids & glycerol Other terms you need to know

8. What are the Two Types of “Active Sites” (shape) model? • Lock & Key model (shape specific) • Substrate& enzymefit together PERFECTLY. • Induced-Fit Model • Enzyme itself changes shape by Stretching and bending to fit the “substrate”.

9. Model of Lock and Key substrate products enzyme substrate complex active site enzyme – unchanged enzyme

10. Correct protein structure • Temperature • pH (acids and bases) level • Concentration of enzyme and substrate What are the factors that affectsenzymes activity (rate of reaction)?

11. 1. How does the order of amino acid (Protein structure) affect enzyme reaction (activity)? • Wrong order wrong shape  cant do its job foldedprotein chain ofamino acids DNA right shape! foldedprotein chain ofamino acids DNA wrong shape!

12. 2. How does the Temperature affect enzyme reaction? • Ideal temperature (WORKS BEST) • 35°- 40°C (body temp = 37°C) • greater numbers of collisions between enzyme & substrate • Raised temperature (Hot) • denature protein unfold loses its shape • Lowered temperature • molecules move slower • fewer numbers of collisions between enzyme & substrate

13. 37° Temperature humanenzymes What’s happening here?! reaction rate temperature

14. 3. How does the pH level (acids & bases) affect enzyme reaction? • Affects on rates of enzyme reaction (activity) • **changes in “pH level” changes protein “shape”** • most human enzymes  pH 6-8 (depends on where in body) • Ex: pepsin (stomach) = pH 3 • trypsin (small intestines) = pH 8 • **Extremesin acid and base (pH level) will unravel or denature the enzyme** • ** Each enzyme has an ideal temperature and pH**

15. The pH Scale • The pH scale measures whether a solution is acid, basic or neutral. • The scale runs from 0 to 14. • A pH of 7 indicates that the solution is neutral. • This means that the solution is neither an acid nor a base.

16. Increase “substrate” will slowdown the reaction rate • Increase “enzyme”will not speed up the rate of reaction **How fast a chemical reaction take places, depends on how much of the substrate & enzymes is available** 4. How does concentration of enzymes and substrateaffects enzymes reactions?

17. Proteins are made of chains of AMINO ACIDS. There are only 20 amino acids andcan be combined in nearly countless ways. The sequence of amino acids determines the shape of the protein. The shape of the protein is the biggest factor that determines its function. There are 4 levels of structure • Primary structure • Linear shape (straight line) • Secondary structure (2 types) • Folding of protein structure • -helix (spiral shape) and -sheets (folded shape) • Tertiary structure • actual 3D shape • Quaternary structure • When 2 or more smaller polypeptides w/ different shapes join together. Any alteration in the structure or sequencing changes the shape and function of the protein What are the structures of proteins?

18. Secondary Protein Structure Amino acid subunits b pleated sheet Amino acid subunits  helix b pleated sheet  helix

19. Polypeptide chain b Chains LE 5-20e Iron Heme a Chains Hemoglobin Polypeptide chain Collagen

20. Because proteins shape are affected by temperature and pH changes. • It loses its normal shape when it is not in ideal optimal environmental conditions. • When a protein loses its normal shape, this is called denaturing. • A denatured protein is biologically INACTIVE. • Denaturing is usually permanent and not reversible. What happens when enzymes (proteins) Denature?

21. Denaturing a Protein Figure 6.5

22. SHAPE! For enzymes…What matters?

23. Structural Differences Between Carbohydrates, Lipids, and Proteins Figure 6.1