1. Mrs. Degl1 Enzymes Enzymes are organic catalysts that are the principle regulators of most chemical activity present in living organisms. Each chemical reaction occurring in an organism requires a specific enzyme. Enzymes regulate the rate (speed) of reactions. Enzymes are known as catalysts. All enzymes end in ase. Enzymes are large complex proteins. Examples: Compound Enzyme maltose maltase lipid lipase

2. 2 The material an enzyme is attached to is called a substrate. After the enzyme attaches to the substrate an Enzyme Substrate Complex is formed and the substrate is broken into two. Enzymes are usually larger than the substrates they interact with. Lock-and-Key Model

3. Mrs. Degl3 The ACTIVE SITE is the location where the enzyme fits into it’s substrate. Only one type of enzyme can fit with only one type of substrate, that is why it is called the Lock-and Key Model. Enzymes may be reused in the cells, however eventually they are destroyed so new ones can be synthesized. Factors that influence enzyme action: 1.Temperature 2.Enzyme and Substrate Concentration 3.pH

4. Mrs. Degl4 How Temperature Influences Enzyme Action As temperature increases, enzyme action increases until the optimum temperature is reached. An increase in temperature above the optimum temperature will cause the enzyme shape to be altered and it denaturizes (breaks down). For human cells, this happens around 40 °C or 104 ° F.

5. Mrs. Degl5 Concentration (amount) of Enzyme/Substrate Influence on Enzyme Action If the amount of the enzyme is kept constant and the substrate concentration is then gradually increased, the reaction velocity will increase until it reaches a maximum. After this point, increases in substrate concentration will not increase the rate of reaction.

6. Mrs. Degl6 The Influence of pH on Enzyme Action Enzyme regulated reaction rates vary according to the pH of the environment. Each enzyme has a different range in which it works best in. Red = Intestinal Protease Green = Gastric Protease

7. Mrs. Degl7 pH for Optimum Activity Enzyme pH Optimum Lipase (pancreas)8.0 Lipase (stomach)4.0 - 5.0 Lipase (castor oil)4.7 Pepsin1.5 - 1.6 Trypsin7.8 - 8.7 Urease7.0 Invertase4.5 Maltase6.1 - 6.8 Amylase (pancreas)6.7 - 7.0 Amylase (malt)4.6 - 5.2 Catalase7.0 What is pH? The pH scale indicates the concentration of H in the environment. The pH scale ranges from 0-14. Acids have a pH less than 7. Bases have a pH greater than 7. A pH of 7 indicates a neutral environment.