Ap Bio Lab 2 : Enzyme Catalysis
Part I - Introduction
Enzymes are proteins that act as catalysts to regulate metabolism by selectively speeding up chemical reactions in the cell without being consumed during the process. During the catalytic action, the enzyme binds to the substrate – the reactant enzyme acts on – and forms an enzyme-substrate complex to convert the substrate into the product. Each type of enzyme combines with its specific substrate, which is recognized by the shape. In the enzymatic reaction, the initial rate of activity is constant regardless of concentration because the number of substrate molecules is so large compared to the number of enzyme molecules working on them. When graphed, the constant rate would be shown as a line, and the slope of this linear portion is the rate of reaction. As time passes, the rate of reaction slowly levels with less concentration of the substrate. This point where the rate starts to level is called the Kmax, in which the peak efficiency of enzymes is reached. In order to start the reaction, reactants require an initial supply of energy called activation energy. The enzymes work by reducing the amount of free energy that must be absorbed so that less required energy leads to faster rate of reaction. The rate of catalytic reactions is affected by the changes in temperature, pH, enzyme concentration, and substrate concentration. Each enzyme has an optimal temperature at which it is most active; the rate of reaction increases with increasing temperature up to the optimal level, but drops sharply above that temperature. Most enzymes have their optimal pH value that range from 6 to 8 with exceptions, and they may denature in unfavorable pH levels. An increase in enzyme concentration will increase the reaction rate when all the active sites are full, and an increase in substrate concentration will increase the rate when the active sites are not completely full. The enzyme used in this lab is catalase, a common catalyst found in nearly all
Enzymes are proteins that act as catalysts to regulate metabolism by selectively speeding up chemical reactions in the cell without being consumed during the process. During the catalytic action, the enzyme binds to the substrate – the reactant enzyme acts on – and forms an enzyme-substrate complex to convert the substrate into the product. Each type of enzyme combines with its specific substrate, which is recognized by the shape. In the enzymatic reaction, the initial rate of activity is constant regardless of concentration because the number of substrate molecules is so large compared to the number of enzyme molecules working on them. When graphed, the constant rate would be shown as a line, and the slope of this linear portion is the rate of reaction. As time passes, the rate of reaction slowly levels with less concentration of the substrate. This point where the rate starts to level is called the Kmax, in which the peak efficiency of enzymes is reached. In order to start the reaction, reactants require an initial supply of energy called activation energy. The enzymes work by reducing the amount of free energy that must be absorbed so that less required energy leads to faster rate of reaction. The rate of catalytic reactions is affected by the changes in temperature, pH, enzyme concentration, and substrate concentration. Each enzyme has an optimal temperature at which it is most active; the rate of reaction increases with increasing temperature up to the optimal level, but drops sharply above that temperature. Most enzymes have their optimal pH value that range from 6 to 8 with exceptions, and they may denature in unfavorable pH levels. An increase in enzyme concentration will increase the reaction rate when all the active sites are full, and an increase in substrate concentration will increase the rate when the active sites are not completely full. The enzyme used in this lab is catalase, a common catalyst found in nearly all