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ENZYMES ENZYMES A type of Protein MADE UP OF WHAT? A folded chain of amino acids In living things they act as Catalysts WHICH MEANS : molecules that are used to speed up a chemical reaction. They take part in the reaction; BUT the enzyme remains unchanged and can be used again. LABEL THE PARTS Products Substrate (Reactant) Active Site The enzyme does not change in the reaction. Therefore an enzyme can be used over and over again. ENZYMES Are needed for all chemical reactions including Dehydration synthesis and Hydrolysis Provide the right “setting” for the chemical reaction Enzyme Activity Demo ENZYMES BREAKDOWN OR BUILDUP CATABOLISM ANABOLISM USE A NEW SET OF WORDS FOR WHAT WE HAVE ALREADY TALKED ABOUT Relate catabolism and anabolism to dehydration synthesis and hydrolysis… HOW DO ENZYMES WORK? Orient the molecules correctly See the animation! Compare enzyme to no enzyme. Increase the likelihood a reaction will occur! This lowers the Activation Energy (Ea) required for a reaction to occur ACTIVATION ENERGY Enzymes make it easier for substrates to react This is how the activation energy is lowered Activation energy The amount of energy needed to convert reactants into products This is the “cost of the reaction” The enzyme is a “coupon” ENERGY PLOT Progress of the reaction CHEMICAL REACTIONS Some reactions require energy input Some chemical reactions release energy Both require activation energy..so look at where the products are on the energy axis. What has more energy, product or reactants? THE CATALYTIC CYCLE OF AN ENZYME Breakdown of Sucrose to Glucose and Fructose Using Sucrase ENZYMES EXHIBIT SPECIFICITY Look at the shape of the substrate and the active site An enzyme is not only substrate specific, but it can only catalyze a reaction in ONE direction. So, it either builds up, or breaks down …but not both SPECIFICITY OF ENZYMES Enzymes are EXTREMELY specific There is a unique enzyme for EVERY substrate that reacts in the body Each enzyme’s active site will ONLY fit one specific substrate LOCK AND KEY (ACTUAL SHAPE) INDUCED FIT THEORY -ENZYMES ACTIVE SITE part of an enzyme where substrates bind and undergo a chemical reaction If this location is changed (damaged, mutated, etc. , the reaction cannot take place. WHAT IMPACTS ENZYMES Temperature All enzymes have an optimal (a “best”) temperature. Exceeding the optimal may cause enzyme inactivation (enzyme doesn’t work) due to breakage of bonds in the 3D structure RESULT: Denaturation (breaking down 3D structure to a polypeptide doesn’t work WHAT IMPACTS ENZYMES pH changing the concentration of H+ interferes with the bonds holding the protein in its folded shape. Raising or lowering pH above or below optimal will cause denaturation. OPTIMAL PH pH is? changing the concentration of H+ interferes with the bonds holding the protein in its folded shape. ENZYMES HAVE SPECIFIC PH DENATURATION Caused by high temperatures and pH changes HOW FAST AN ENZYME WORKS ALSO DEPENDS ON: The ratio of the the substrate to the enzyme. Look at the graph…what does it tell us about “velocity” (speed of the reaction) and substrate concentration? Concentration of the Enzyme Concentration of the Substrate (what it is putting together or taking apart). SATURATION CURVE What does this tell us? Why does this happen ? COENZYMES AND COFACTORS Coenzymes Organic molecules such as vitamins Cofactors Inorganic molecules or ions such as Zn and Cu Both attach to enzymes and improve chances that substrate will bind to the enzyme. ENZYME INHIBITION Inhibit: shut down or suppress Can be caused by outside molecule – drugs/poisons Can be caused by inside molecule if your body wants to temporarily shut down a reaction Why waste the energy? COMPETITIVE INHIBITION molecules that are similar in shape to the substrate bind to the active site and block the substrate; No chemical reaction can happen Examples: Drugs and Insecticides NON-COMPETITIVE INHIBITION molecule binds to a part of the enzyme and alters the shape of the active site; No chemical reaction INTERPRETING ENZYME GRAPHS What is the optimum temperature for this enzyme? INTERPRETING ENZYME GRAPHS Would this make a good human enzyme?
