Investigating how quickly the enzyme catalase breaksdown hydrogen peroxide.

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Investigating how quickly the enzyme catalase breaks

down hydrogen peroxide

I will be investigating the enzyme catalase and the factors affecting the rate at which it speeds up the breakdown of hydrogen peroxide. I will be carrying out this experiment to find out if certain factors speed up the reaction at different rates.

An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions take place without the enzyme being altered in the process. The name enzyme was suggested in 1867 by the German physiologist, Wilhelm Kuhne (1837 – 1900), and it comes from the Greek phrase en zyme, which means “in leaven”. The biological processes that occur within all living organisms are chemical reactions and most are regulated by enzymes. Without enzymes, many of these reactions would not take place at a distinguishable rate. The faster a reaction happens, the more gas it gives off and its temperature increases.

Enzymes also have valuable industrial and medical uses. The fermenting of wine, leavening of bread, curdling of cheese and brewing of beer have been practiced from earliest times, but not until the 19th Century were these reactions understood to be the result of catalytic activity of enzymes. The uses of enzymes in medicine include killing disease-causing microorganisms, promoting wound healing, and diagnosing certain diseases. Enzymes are classified into several broad categories, such as hydrolytic, oxidizing and reducing, depending on which type of reaction they control. Hydrolytic enzymes accelerate reactions in which a substance is broken down into simpler compounds through reaction with water molecules. Oxidizing enzymes, known as oxidases, accelerate oxidation reactions; reducing enzymes speed up reduction reactions, in which oxygen is removed. Many other enzymes catalyze other types of reactions. Individual enzymes are named by adding ase to the name of the substrate with which they react. Most enzymes are specialized to break down their specific substrate and no other.

         

Substrate                        Enzyme                        Product

STARCH + water                amylase                        maltose

MALTOSE + water                maltase                        glucose

PROTEINS + water                protease                        (poly) peptides

                                1) pepsin   2) trypsin

PEPTIDES + water                peptidase                        amino acids

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FAT + water                        lipase                                fatty acids + glycerol

Enzymes are proteins and temperature sensitive. They have an optimum pH and temperature, which affects their ability to speed up reactions.

Until recently it was thought that all biological catalysts were enzymes, but now we know that other substances, such as abzymes and ribozymes may carry out catalytic functions in living organisms. Enzymes are not used up or altered in chemical reactions so they may be used over and over again. They are therefore effective in small amounts. Enzymes cannot cause reactions to occur, but only speed up ones, which would otherwise take ...

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