How are enzymes catalysts in living systems?
Mohammad Sharif 9/26/08
Enzymes are the catalyst of the cell, meaning the speed up the rate of all reactions without being used up. This helps the enzyme be used over and over again. All enzymes are proteins, which are polymers that are made up of amino acids. These amino acids become proteins when they are linked together by polypeptide bonds. These enzymes/proteins, act like catalysts due to their sequence of amino acids in the polypeptide chains. This sequence of their amino acids will eventually become the overall shape of the enzyme, the shape is three dimensional. When the three dimensional shape is formed, the active site also is formed, this is where the catalysis process occurs. The active site will have a place where the substrate or even substrates will come and attach themselves to the enzymes. After the substrate binds to the enzyme, the substrate is held in position, and this makes it more likely to undergo a reaction, rather than if it was in a solution without an enzyme. This lowers the Delta G, and as we know it, this lowers the activation energy of the reaction. An enzyme may also be used for two different reactions at once. Since it is being used for an exothermic reaction along with an endothermic reaction, this allows the enzyme to use the free energy released by the exothermic reaction to be used in the endothermic reaction. A large variety of enzymes are used for many different endothermic reactions to the exothermic reaction, for example, when ATP is converted by hydrolysis into ADP.
Enzyme activity is affected by many different things, one factor is temperature. Most enzymes have optimum temperatures of 37°C. If the temperature is too low the enzyme would work slower than usual because there is not enough energy in the...