Enzymes Class Notes PDF

# Enzymes and Their Action ## Enzymes Proteins that are biological catalysts that are involved in all metabolic reactions ## Lock and Key Mechanism - The enzyme is like a lock. - The substrate has a complementary shape to the active site of the enzyme so it can fit in like a key. - Formation of...

# Enzymes and Their Action ## Enzymes Proteins that are biological catalysts that are involved in all metabolic reactions ## Lock and Key Mechanism - The enzyme is like a lock. - The substrate has a complementary shape to the active site of the enzyme so it can fit in like a key. - Formation of the enzyme-substrate complex. - The enzyme changes the substrate into new molecules called products. ## Enzymes Actions - Amylase (saliva) - Breaks starch into maltose - Protease: trypsin/ pepsin (stomach protease) - Breaks proteins into amino acids - Carbohydrase - Breaks carbohydrates into glucose - Lipase (small intestine) - Breaks fats/ LIPIDS into fatty acids and glycerol - Maltase - Breaks maltose into glucose - Catalase - Breaks hydrogen peroxide into water and oxygen - Cellulase (plants) - Breaks cellulose / cell wall The document contains an illustration on this page titled "Figure 5.2 The lock and key mechanism" which describes the process with labeled imagery. This image depicts an enzyme (labeled as a lock shape) and a substrate (shaped as a key). It explains that the substrate must be a perfect fit with the enzyme and that the enzyme changes the substrate into new molecules called products. ## Possible explanation of enzyme action The document includes a second diagram titled “Figure 5.2 Possible explanation of enzyme action" which details the following steps: - The enzyme and molecule of two substances (A and B) come together and combine with the enzyme's active site for a short time. - The molecule breaks at this point. - The enzyme's active site combines with the substance for a short time. - The enzyme is free to take part in the next reaction. - Two substances are produced. ## How an enzyme works - The substrate molecule (starch) slots into the active site. - The starch is split into maltose molecules. The enzyme is unaltered and ready to accept another part of the starch molecule. - Each enzyme has an active site into which its substrate molecule fits exactly. - This enzyme is amylase and its active site is just the right size shape for a starch molecule. The document presents a diagram titled "Figure 5.3 How an enzyme works" which illustrates the enzyme's active site and shows how the starch is broken down. ## Summary - **substrate enzyme product** - **starch amylase maltose** ## Enzymes Exapmles Actions - Protease: - Breaks proteins into amino acids - Carbohydrase - Breaks carbohydrates into glucose - Lipase (small intestine) - Breaks fats/LIPIDS into fatty acids and glycerol - Amylase (saliva) - Breaks starch - Maltase - Breaks maltose # Properties of Enzymes | Property | Description | |---|---| | All enzymes are proteins | | | All enzymes are catalysts | They are not changed by the chemical reaction and can be used over and over again | | All enzymes are specific | Each enzyme will catalyze one kind of chemical reaction | | Are made inactive by high temperature | Because proteins are denatured/damaged by heat | | Work best at a particular temp. / optimum temp | Enzymes in body work best at 37'C. Enzymes in plants work best at 28'C to 35'C. Enzymes in bacteria work best at 75'C. |