Linda J. Porrino, Ph. David P. Friedman, Ph. Leslie Morrow, Ph. Kathleen K. Sulik, Ph. Search Search. Enzymes as Catalysts Enzymes are proteins that have a specific function. Enzymes are a form of catalysts that speed up chemical reactions by lowering the activation energy. Catalysts are not consumed in the reaction. For example, iron is a metal used to produce ammonia from nitrogen and hydrogen.
Platinum is used to produce nitric acid from ammonia. Vanadium V oxide is used to produce sulfuric acid. Vanadium V oxide powder is shown in figure 2.
An enzyme is a biological macromolecule produced by living organisms to catalyze the biochemical reaction inside the cell at body temperatures.
The function of an enzyme is indispensable to the maintenance of life. All biochemical reaction occurring in living organisms depend on catalysts. Up to now, the action of around 4, enzymes are well known. Enzymes act in mild conditions such as body temperature and pH. They catalyze the reactions of building and breakdown of materials inside the living organisms.
The function of the enzymes is highly specific. Most of the enzymes are made up of globular proteins with high molecular weights. The globular proteins are rearranged into multi-protein complexes. Some enzymes require the assistance of cofactors for their action. The enzyme can be inhibited or activated by the binding of cofactors to the enzyme.
Figure 3: Glucosidase Enzyme. Enzymes are classified into six types based on the type of reaction they catalyzed. They are oxidoreductases, transferases, lyases, hydrolases, ligases, and isomerases. The enzyme glycosidase, which converts maltose into two glucose molecules, is shown in figure 3. Catalyst: A catalyst is a substance that increases the rate of a chemical reaction, without undergoing any permanent chemical change.
Enzyme: An enzyme is a biological molecule produced by living organisms, which catalyzes a specific biochemical reaction at body temperatures. Catalyst: Catalyst can be either inorganic catalysts or enzymes.
Catalyst: Inorganic catalysts are mineral ions or small molecules. Catalyst: Inorganic catalysts are similar in size to the substrate molecules. Enzyme: Enzymes are quite larger than the substrate molecules.
Catalyst: Inorganic catalysts have a low molecular weight. Enzyme: Enzymes have a high molecular weight. Catalyst: Inorganic catalysts act on physical reactions. Enzyme: Enzymes act on biochemical reactions.
There also exists RNA based enzymes called ribozymes. Enzymes are substrate specific and usually are larger than their respective substrates.
Only a small part of an enzyme takes part in a enzymatic reaction. The active site is where substrates bind to enzyme for facilitating the reaction. Other factors like co factors, direct products, etc also have specific binding sites on enzyme. Enzymes are made of long chains of amino acids that fold over each other giving rise to a globular structure.
The amino acid sequence gives enzymes their substrate specificity. Heat and chemical can denature an enzyme. Both catalysts and enzymes lower the activation energy of a reaction thereby increasing its rate. A catalyst can be positive increasing reaction rate or negative decreasing reaction rate in nature. They react with reactants in a chemical reaction to give rise to intermediates that eventually release the product and regenerate the catalyst. The catalyst is regenerated in the last step even though in the intermediate steps it had integrated with reactants.
The mechanism of enzymatic action follows the induced fit model as suggested by Daniel Koshland in According to this model, substrate is molded into the enzyme and there can be slight changes in shape in enzyme and substrate as the substrate binds itself at the active site of enzyme to form the enzyme substrate complex. A catalytic converter used in cars is a device that removes gases causing pollution from car exhaust systems.
Platinum and Rhodium are the catalysts used here which break down dangerous gases into harmless ones. For e. The enzyme amylase aids in digestion of conversion of complex starch into more easily digestible sucrose. Catalysts are used in energy processing; bulk chemicals production; fine chemicals; in the production of margarine and in the environment where they play a critical role of chlorine free radicals in the breakdown of ozone.
Enzymes are used in food processing; baby foods; brewing; fruit juices; dairy production; starch, paper and bio fuel industry; make-up , contact lens cleansing; rubber and photography and molecular biology. Share this comparison:. If you read this far, you should follow us:.
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