1 Enzymes

Catalysts Catalysts are chemicals that make a chemical reaction go faster. 2

Catalysts Catalysts are conserved in the reaction. Meaning they don’t get used up. The same amount of catalyst you start with is the same amount you end with. 3

4 What Are Enzymes? Enzymes are catalysts that can be found in living things. Your body is full of enzymes.

5 What Are Enzymes? ProteinsMost enzymes are Proteins Examples: –Lysosomes have digestive enzymes to break down worn out organelles. –Amylase in your saliva turns starch into sugar. –Lipase in your stomach breaks down the fat that you eat. –Hydrogen peroxide in your cells builds up and could kill you, catalase breaks it down.

6Enzymes catalyzeAre specific for what they will catalyze ReusableAre Reusable aseEnd in –ase-Sucrase-Lactase-Maltase

7 How do enzymes Work? weakening bonds which lowers the energy needed for the reaction (activation energy) Enzymes work by weakening bonds which lowers the energy needed for the reaction (activation energy)

8 How do enzymes Work? If reactions require a lower activation energy then they start quicker. So they take less time.

9Enzymes Free Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

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11 Enzyme-Substrate Complex substance enzyme substrate The substance (chemical) an enzyme acts on is the substrate Enzyme Substrate Joins

12 Active Site substrate binds to the active site of an enzymeA substrate binds to the active site of an enzyme. Enzyme Substrate Active Site

13 Induced Fit When a substrate binds the enzyme changes shape. Nothing else can bind now.

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

15 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). High or low pH causes the enzyme to not work 3.Ionic concentration (salt ions). Ions can bind to the enzyme or substrate and change its shape making it harder (or sometimes easier) to bond.

16 2. Cofactors and Coenzymes Inorganic substances (zinc, iron) vitamins enzymatic activityInorganic substances (zinc, iron) and vitamins are sometimes need for proper enzymatic activity. Example:Example: Iron pick up oxygen. Iron must be present in the red blood cell in order for it to pick up oxygen.

17 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

18Inhibitors 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