Effects of temperature on enzyme catalyzed reactions doc

Effects of temperature on enzyme catalyzed reactions Lecturer: Msc. Le Hong Phu GROUP’S MEMBER • Trần Lê Đan Hà BT070026 • Mã Bích Như BT070153 • Tô Bảo Châu BT070011 • Lê Phương An BT070004 • Bùi Nhất Tiên BT070079 CONTE NT Introduction Effects of temperature on enzyme-catalyzed reactions Example and Application Conclusion • Living processes consists almost entirely of biochemical reactions. Without catalysts these reactions would not occur fast enough to sustain life. How does an enzyme do this? > because enzyme is a catalytic protein-a chemical agent that changes the rate of a reaction without being consumed by the reaction Introduction about enzyme-catalyzed reaction. Optimal temperature of human enzyme is about 35-40ºC, of bacteria is about 70ºC or higher Factor effects on enzyme-catalyzed reaction Fig 1. 32. Examples of interactions contributing to the tertiary structure of a protein. Hydrophobic side chains usually end up in the interior of a protein, away from water. Along with this clustering of hydrophobic groups, misleadingly called hydrophobic interactions, hydrogen bonds, ionic bonds, and van der Waals interactions are all weak interactions (weak bonds) between side chains that collectively hold the protein in a specific conformation. Much stronger are the disulfide bridges, covalent bonds between the side chains of two cysteine amino acids. This diagram shows only one small part of a hypothetical protein. Low temperatures slow the rate of formation of the enzyme-substrate complex because the molecules move at slower speeds and so do not come in contact with one another as frequently. As the temperature rises, the substrate and enzyme molecules vibrate more and they have a higher chance of coming together (collision) to form an E-S-complex. Therefore the rate of enzyme reaction increases. As the reaction temperature (), enzyme activity also increases (). Factor effects on enzyme-catalyzed reaction At the optimum temperature, the rate of enzymatic reaction is at a maximum The enzyme works best because substrates collide with active sites more frequently when the molecules move rapidly At temperature higher than the optimum, the reaction becomes inhibited as the enzyme molecule vibrates too much and the shape of the active site becomes unfit for the substrate. At extreme temperature, enzyme molecule, being protein, has its shape permanently changed. The active site does not fit the substrate, the enzyme is denatured. The reaction rate is zero. When enzymes are heated up too much, they vibrate so vigorously that the bonds holding the protein structure in its specific shape becomes broken. The enzyme shape changes and the substrate no longer fits in to the active site. the enzyme can become denatured and lose all function [...]... Tube 1 Observation Application • Temperature has an important role in industry, agriculture, biomedical and many fields in life • Depending on the optimal temperature of each enzyme, we can provide the appropriate temperature range for enzyme to work best, so we can get the highest productivity as we need Conclusion • An enzyme' s function is dependent upon its shape environmental conditions which affect... affect the catalytic properties of the enzyme – As the temperature raises, enzyme activity also increases – At low temperature, the reaction rate is very slow as the enzyme is inactive so the rate of enzyme reaction is inhibited – At the optimum temperature, the rate of enzymatic reaction is at a maximum The enzyme works best – At temperature higher than the optimum, enzyme molecule, being protein,... collisions and therefore the rate of reaction will double This will only be so until the enzyme denatures after its optimum temperature: 40 - 45°C Predictions: I predict that the enzyme will become denatured, and therefore will work at a slower rate after 40 45°C I think the reason for this prediction is because every enzyme has a temperature range of optimum activity Outside that temperature range the enzyme. .. that as temperature increases, the rate of reaction also increases However, the stability of the protein also decreases due to thermal degradation Holding the enzyme at a high enough temperature for a long period of time may cook the enzyme Reaction rate is the speed at which the reaction proceeds toward equilibrium For an enzyme- catalysed reaction, the rate is usually expressed in the amount of product... between reactions and products governs reaction rate In general, energy must be added to the reactants to overcome the energy barrier This added energy is termed "activation energy", and is recovered as the reactants pass over the barrier and descend to the energy level of the products Enzymes can accelerate the rate of a reaction Catalysts accelerate the rates of reactions by lowering the activation energy... reactions by lowering the activation energy barrier between reactants and products All chemical reactions speed up as the temperature is raised As the temperature increases, more of the reacting molecules have enough kinetic energy to undergo the reaction Since enzymes are catalysts for chemical reactions, enzyme reactions also tend to go ... inactive This occurs because as the temperature changes enough energy is supplied to break some of the molecular bonds When these forces are disturbed and changed the active site becomes altered in its ability to accommodate the substrate molecules it was intended to catalase Most enzymes in a human body shut down beyond certain temperatures This can happen if body temperature gets too low (hypothermia),... shape permanently changed The active site does not fit the substrate, the enzyme is denatured The reaction rate is zero References • Campbell & Reece, Biology, sixth edition • Biochemistry (4th edition) Lubert Strayer • http://student.ccbcmd.edu/biotutorials/proteins/e nzyme.html • http://www.worthingtonbiochem.com/introbiochem/tempEffects.html • http://academic.brooklyn.cuny.edu/biology/bio4fv /page/enz_act.htm...Example Effects on enzyme performance • Catechol oxidase is an enzyme that produces a colored compound from a colorless precursor in fruits and vegetables • The browning is caused by a reaction between catechol and oxygen • Benzoquinone has brown colour Experiment Tube 2 Tube 3 Tube 4 Tube 5 10 ml Water 10 ml Water 10 . BT070079 CONTE NT Introduction Effects of temperature on enzyme- catalyzed reactions Example and Application Conclusion • Living processes consists almost entirely of biochemical reactions. Without. consumed by the reaction Introduction about enzyme- catalyzed reaction. Optimal temperature of human enzyme is about 35-40ºC, of bacteria is about 70ºC or higher Factor effects on enzyme- catalyzed. reaction increases. As the reaction temperature (), enzyme activity also increases (). Factor effects on enzyme- catalyzed reaction At the optimum temperature, the rate of enzymatic reaction