Agenda 1/8 Enzyme Notes Enzyme modeling activity Turn in: Water POGIL ONLY Homework: Enzyme graphing worksheets, enzyme video and notes 1

Enzymes: The Biological Catalysts

Energy of Activation The energy used to break the bonds in the reactants so they can be reformed in the products is called the energy of activation. 3

Enzymes Enzymes are biological catalysts that increase the reaction rate of biochemical reactions. 4 Characteristics of enzymes A. Made of proteins (or RNA). B.They are very specific and only work with a certain set of reactants or substrates that fit on their active site. The enzyme shown is lysozyme

Enzyme Vocabulary Substrate- These are reactants that interact with the enzyme during a biochemical reaction. Active site- This is the part of the enzyme actually involved in the chemical reaction. 5

Induced Fit C.Enzymes can be used over and over again. D.When an enzyme binds with the substrate, the substrate interacts with the enzyme causing it to change shape. This change in shape facilitates the chemical reaction to occur. This is called the induced fit. 6

Enzyme Example Ribonuclease Ribonuclease (RNAse) decomposes RNA, and the nucleotides can be recycled. The purple part is the enzyme; the green part is the substrate (RNA). 7

Enzymes Work by Lowering the Energy of Activation E.Enzymes increase the reaction rate by lowering the energy of activation. They do NOT change Gibbs free energy or  G. 8

The Enzyme Sucrase Decomposing Sucrose 9

Mechanism of Enzymes 10

Initial Velocity The reaction rate of an enzymatic reaction is always fastest at the beginning of the reaction when there is the greatest concentration of substrate. Why? 11

Effect of Increasing Substrate Concentration 12

Effect of Increasing Temperature and Reaction Rates 13

Effect of Varying pH and Enzymatic Reaction Rates 14

Effect of Competitive Inhibitors and Enzymatic Reaction Rates 15

Effect of Noncompetitive Inhibitors and Enzymatic Reaction Rates 16

Effect of Allosteric Regulation 17 Allosteric Regulation-= regulation by changing the structure of a molecule (allosteric = Greek for “different structure”).

Feedback Inhibition 18

Cooperativity 19