SOL Addressed: Bio 2.b,c Enzymes Ranny Copenhaver Catalase

SOL Addressed: Bio 2.b,c What is an enzyme? Known as a BIOLOGICAL CATALYST- a catalyst that is found in an organism A catalyst is something that speeds up (usually) or slows down a chemical reaction without changing itself. Manganese Dioxide in Hydrogen Peroxide Biological catalysts speed up reactions in living cells

SOL Addressed: Bio 2.b,c Activation Energy Catalysts or enzymes do this by lowering the ACTIVATION ENERGY - the energy required for a reaction to begin Progress of reaction Energy Uncatalysed reaction Catalysed reaction

SOL Addressed: Bio 2.b,c Properties of Enzymes They are made of PROTEIN They are not changed by the reactions they speed up They are SPECIFIC- means that only one particular enzyme will work with one particular substrate

SOL Addressed: Bio 2.b,c Naming Enzymes Most Enzymes are named by taking the name of the substrate, dropping off the ending and adding “–ase”. For example: the sugar, sucrose is broken down by sucrase. lactose is broken down by lactase. lipids (fats and waxes) are broken down by lipase.

SOL Addressed: Bio 2.b,c Some other terms you need to know Substrate – the substance that the enzyme works on- example: Amylase works on it’s substrate, starch Product – the substance that is made by the reaction- example: In the breakdown of starch by Amylase the product is Maltose- a more simple sugar.

SOL Addressed: Bio 2.b,c Amylase Found in saliva and in the pancreas Breaks STARCH down to MALTOSE You can place a saltine cracker in your mouth and hold it there. After a few moments, the cracker begins to taste sweet! It is turning into maltose- a simple sugar!!

SOL Addressed: Bio 2.b,c Another enzyme- CATALASE Found in animal and plant cells Catalase to solves a vicious problem. When cells metabolize food in the presence of oxygen, most produce hydrogen peroxide as a side product. Hydrogen peroxide kills cells. The dilemma: cells must extract energy from food to live. But the process can produce a poison that kills them. The solution: manufacture a rescue catalyst that changes hydrogen peroxide to harmless water and oxygen and make that reaction happen: fast! Needed to speed up the breakdown of HYDROGEN PEROXIDE Breaks it down to OXYGEN and WATER Catalase is found in beef liver. A piece of beef liver in Hyrodgen Preoxide

SOL Addressed: Bio 2.b,c Remember- Specific Enzymes breakdown specific substances This means amylase will only breakdown starch Catalase will only breakdown hydrogen peroxide Amylase will NOT breakdown hydrogen peroxide Catalase will NOT breakdown starch

SOL Addressed: Bio 2.b,c Lock and Key All enzymes have a special shaped area that fits onto their substrate This area is called the ACTIVE SITE This Active Site will fit onto the substrate while the reaction takes place Because it fits like a lock and key we call this the lock and key mechanism or hypothesis

SOL Addressed: Bio 2.b,c Model of Lock and Key in which a substrate is broken down products substrate enzyme enzyme – unchanged active site enzyme substrate complex

SOL Addressed: Bio 2.b,c Lock and Key- sometimes enzymes help bond substrates to form a new substance

SOL Addressed: Bio 2.b,c Effect of Temperature Speed of reaction increases until an Optimum temperature is reached Optimum temperature is the temperature at which the enzyme works best After this point the rate of reaction decreases until there is no reaction At this point enzyme is said to be DENATURED – active site destroyed

SOL Addressed: Bio 2.b,c Effect of pH Most enzymes have an optimum pH of 7 Some enzymes have a different optimum pH for example pepsin has an optimum pH of 2 Pepsins main site of activity Breaking down food is in the very acidic stomach (pH 1.5 to 2) Trypsin works to break down proteins in the first part of the intestine where the pH is 7

SOL Addressed: Bio 2.b,c More to do Design an experiment that you might use to find how temperature might affect on the activity of an enzyme. – Groups of no more than 4 – Choose a group leader – Choose a group recorder

SOL Addressed: Bio 2.b,c Sources Wake Forest University Baptist Medical Center. "Hydrogen Peroxide Has A Complex Role In Cell Health." ScienceDaily, 4 Jan Web. 22 Sep Crook, James. "Catalase - An Extraordinary Enzyme." Catalase Website. N.p., 5 Jul Web. 22 Sep "Role of Enzymes in Biochemical Reactions." Virtual Chembook. Elmhurst College, n.d. Web. 22 Sep McCarte, M. "Enzymes." WikiSites. Castlehead High School. Web. 22 Sep