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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 molecules that are used to speed up a chemical reaction without being changed in the reaction; the enzyme can be used over and over again LABEL THE PARTS Substrate (Reactant) Products Active Site Enzyme is unchanged WHEN WE EAT ENZYMES…. We can’t use them…what has to happen first? ENZYMES Break down enzymes (like any protein) in the digestive system. Our enzymes are made by assembling these amino acids to form “human” proteins Enzyme Activity Demo ENZYMES Are needed for all chemical reactions including Dehydration synthesis and Hydrolysis Provide the right “setting” for the chemical reaction HOW DO ENZYMES WORK? Orient the substrate molecules correctly Increase the likelihood a reaction will occur! Enzyme Demo 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 chemical reactions release energy What has more energy, product or reactants? What type of reaction is this? Some input reactions require energy Answer the two questions above again! HOW DO ENZYMES WORK? CATABOLISM ANABOLISM THE CATALYTIC CYCLE OF AN ENZYME Breakdown of Sucrose to Glucose and Fructose Using Sucrase BUILDING REACTIONS USE…. Breakdown reactions ……… Using different words for the same event….. 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 MODEL 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 temperature. Exceeding optimal may cause enzyme inactivation (denaturation) due to breakage of bonds in quaternary and tertiary structures. 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: 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. Cofactor animation ENZYME INHIBITION Inhibit: shut down or suppress Can be caused by outside molecule – drugs/poisons (poisons, drugs Can be caused by inside molecule if your body wants to temporarily shut down a reaction Why waste the energy? EXAMPLES – EXTERNAL Cyanide inhibits one of the enzymes in cellular respiration (oxidase) RESULT: less oxygen less ATP death Penicillan works by inhibiting a bacterial enzyme involved in making the cell wall. The bacteria is unable to reproduce. Nerve gas interferes with acetylcholinesterase RESULT: acetylcholine cannot be hydrolyzed nerve signals cannot be passed from nerve cell to nerve cell. EXAMPLE - INTERNAL Feedback inhibition in a biochemical pathways Feedback inhibition is a form of inhibition 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 ANIMATION INHIBITION 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?
