1. Enzymes Objective: Identify and understand the role of enzymes

2. Chemical Reactions A chemical reaction is when bonds are broken and reformed to make different substances. Reactant/SubstratesProducts Ex. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O glucose oxygen carbon dioxidewater

3. Role of Enzymes Increase biochemical reaction rates Help regulate cell metabolism Enzymes

4. Characteristics of Enzymes: Name usually ends in suffix –ase, often derived from name of substrate – Maltase – enzyme that helps split maltose What enzyme splits sucrose?______________ What enzyme splits lactose?_______________ Enzymes

5. Bind to specific substrate(s) Able to facilitate the reaction of large quantities of substrate Enable cell reactions to proceed at biological temperatures Work best at certain temperatures and pH Enzymes

6. Enzyme – protein that acts as a biological catalyst Catalyst – substance that affects a chemical reaction without being used up themselves Enzymes

7. Active site – location on the enzyme where reaction occurs Substrate – substance that an enzyme acts upon Product – substance that is created Enzymes

8. Activation Energy How could you speed up this chemical reaction? Energy absorbed Activation energy Reactant Products Energy released

9. Activation Energy Lowering the activation energy will speed up the reaction Energy absorbed Energy released Reactant Products Activation energy

10. Activation energy - the minimum energy needed to cause a chemical reaction to occur Enzymes lower the activation energy!!!! How Enzymes Work

11. Two theories of how enzymes bind to substrates Lock-and-Key Model – substrate molecule fits into enzyme just like a key fits into a lock Induced Fit Model – enzyme’s shape changes slightly to bind with substrate – More widely accepted How Enzymes Work

12. Substrate molecule fits into active site on enzyme – “Enzyme-substrate complex” Enzyme shape changes slightly to bind to substrate – “Induced fit” Enzyme catalyzes a chemical reaction in the substrate – Involves breaking or forming chemical bonds Products are released Enzyme is ready to bind to another substrate E + S  ES  E + P How Enzymes Work-Order of Business

13. Enzyme Active site Substrate Product Sucrose Glucose + Fructose sucrase Enzymatic Reaction Enzyme Substrate Complex