Lab Report on Measuring the Rate of Conversion of Hydrogen Peroxide using Enzyme Catalysis

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Lab Report on Measuring the Rate of Conversion of Hydrogen Peroxide using Enzyme Catalysis

In essence, the main objective was to use chemical titration to measure and then calculate the rate of conversion of hydrogen peroxide (H2O2) to water and oxygen by using the enzyme catalase. Other purposes of the lab were; to measure the effects of changes of temperature, pH, enzymes concentration, and substrate concentration on rates of an enzyme. The lab was also an opportunity to see a catalyzed reaction in a controlled experiment. And the last objective was to learn how environmental factors affect the rate of enzyme catalyzed reactions.

Enzymes are proteins produced by living cells. They act as catalysts in biochemical reactions. A catalyst speeds up the rate of a chemical reaction and makes it possible for the reaction to occur with a lower initial input of energy. One benefit of enzyme catalysis is that the cell can carry out complex chemical activities at a relatively low temperature (AP Lab Manual).

In biochemical reactions, the enzyme, E, combines reversibly with its specific substrate, S, to form a complex ES. One result of this temporary formation is a reduction in the energy required to activate the reaction of the substrate molecule so that P, the products of the reaction are formed. In summary: E+SESE+P. The enzyme is not changed in the reaction and can break down additional substrate molecules (Lab Bench).

The enzyme used in this lab is catalase. Catalase has a molecular weight of approximately 240,000 daltons and contains four polypeptide chains, each composed of more than 500 amino acids. This enzyme occurs universally in aerobic organisms. One function of catalase within cells is to prevent the accu...

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...n activator, or if it decreases the reaction rate it is an inhibitor. These molecules can regulate how fast the enzymes act. Any substance that tends to unfold the enzyme, such as an organic solvent or detergent, will act as an inhibitor. Some inhibitors act by reducing the -S-S- bridges that stabilize the enzyme's structure. Many inhibitors act by reacting with the side chains in or near the active site to change its shape or block it. Many well known poisons such as potassium-cyanide and curare are enzyme inhibitors that interfere with the active site of critical enzymes (Enzyme Catalysis).

Bibliography:

References:

"Enzyme Catalysis" sc2000.net. 1page. 21, Feb. 2002

"Lab Bench: Enzyme Catalysis" Biology.com. Pg. 1-3. 21, Feb. 2002 http://www.biology.com/learning/enzyme/concepts.html

AP biology lab manual (appropriate reference and date N/A)

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