1. Enzymes

2. Question: enzymesWhat are enzymes?

3. Enzymes Answer: 1.Proteins:enzymesproteins tertiaryquaternary structures. 1.Proteins:most enzymes are proteins, primarily tertiary and quaternary structures. 2.Catalyst:chemical agentaccelerates 2.Catalyst:chemical agent that accelerates a reaction without being permanently changed in the process.

4. Enzymes 3.Selective: catalyze(Specificity - depends upon 3D shape). 3.Selective:enzymes are specific for which they will catalyze (Specificity - depends upon 3D shape). 4.Recycled: 4.Recycled: enzymes are reusable. 5.“ase”examples:sucrase 5.“ase” endings:examples:sucrasemaltaselactase

5. Question: enzymesHow do enzymes work?

6. Enzymes Answer: Enzymes lowering the free energy of activationEnzymes speed up the cell’s chemical reactions by lowering the free energy of activation.

7. Enzymes Free Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

8. Substrate substanceenzymeThe substance (reactant) an enzyme acts on. Enzyme Substrate

9. Active Site restricted region enzyme bindssubstrateA restricted region of an enzyme molecule which binds to the substrate. Enzyme Active Site Substrate

10. Induced Fit changeconfigurationenzyme’s active siteA change in the configuration of an enzyme’s active site (H and ionic bonds are involved). Inducedsubstrate.Induced by the substrate. Enzyme Active Site substrate induced fit

11. Enzymatic Reaction substrate (sucrose)enzyme (sucrase)  substrate (sucrose) + enzyme (sucrase)  enzyme-substrate complex  and+ sucrase glucosefructose glucose fructose products +enzyme

12. What Affects Enzyme Activity? Three factors:Three factors: 1.Environmental Conditions 2.Cofactors and Coenzymes 3.Enzyme Inhibitors

13. 1. Environmental Conditions Enzymatic reactions environmental conditionsEnzymatic reactions are very specific. The following environmental conditions affect enzymatic reactions: 1.Temperature (extremes most dangerous): - high temps denature enzyme. - high temps may denature the enzyme. 2.pH (most like 6 - 8 pH - neutral) 3.Ionic concentration (salt ions)

14. 2. Cofactors and Coenzymes Inorganic substances (zinc, iron) vitamins enzymatic activityInorganic substances (zinc, iron) and vitamins (respectively) are sometimes need for proper enzymatic activity. Example:Example: Ironquaternary structure-hemoglobin Iron must be present in the quaternary structure - hemoglobin in order for it to pick up oxygen.

15. 3. Enzyme Inhibitors Two examples:Two examples: a.Competitive inhibitors: resembleenzyme’s normal substrate competeactive site a.Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site. Enzyme Competitive inhibitor Substrate

16. 3. Enzyme Inhibitors b.Noncompetitive inhibitors: do not enter the active site bind to another part enzyme enzymechange its shape alters the active site Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn alters the active site. Substrate Enzyme active site altered Noncompetitive Inhibitor