1 Enzymes

2 What Are Enzymes? Proteins.Most enzymes are Proteins. CatalystsAct as Catalysts to accelerate a reaction.

3Enzymes catalyzeEach enzyme is a specific shape for it they will catalyze aseEnd in –ase-Sucrase-Lactase-Maltase

4 How do enzymes Work? weakening bonds which lowers activation energy (the energy needed to start a reaction). Enzymes work by weakening bonds which lowers activation energy (the energy needed to start a reaction).

5Enzymes Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

6 Enzyme-Substrate Complex substanceenzyme substrate. The substance an enzyme acts on is the substrate. Example: Coenzyme A works on Pyruvic Acid. CoEnzyme A Substrate (Pyruvic Acid) Joins

7 Active Site restricted region enzyme.Binds substrate that has the same shapeThe active site called the restricted region of an enzyme. Binds to the substrate that has the same shape. Enzyme Substrate Active Site

8 Induced Fit shapeA change in the shape of an enzyme’s active site InducedInduced by the substrate

9 Induced Fit changeconfiguration enzyme’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

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

11 1. Environmental Conditions 1. Extreme Temperature are the most dangerous 1. Extreme Temperature are the most dangerous - high temps denature (unfold) enzyme. - high temps may denature (unfold) the enzyme. 2.pH (most like pH near neutral) 3.Ionic concentration (salt ions)

12 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: Ironhemoglobin pick up oxygen. Iron must be present in hemoglobin in order for it to pick up oxygen.

13 Two examples of Enzyme Inhibitors a. Competitive inhibitors: resemble enzyme’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

14Inhibitors b.Noncompetitive inhibitors: do not enter the active sitebind to another part enzymeenzyme change 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. Enzyme active site altered Noncompetitive Inhibitor Substrate