Although the enzyme works totally independently, there are some techniques that we could implement to control or effect the reaction.
Small changes in the pH medium usually have dramatic effects on the efficiency of enzymes. At values only slightly above and below the optimum pH there is highly noticeable fall in efficiency. Unlike the effects of pH are normally reversible, with in limits. Restoring the pH back to normal will usually restore the rate of reaction. Amino acids, from which all proteins are made, contain both acidic and basic groups, and in a polypeptide chain there are many of these acidic and basic groups. The secondary and tertiary structure of the enzyme is maintained by bonds between these groups, and other interactions. A change of pH in the environment of the protein alters the ionic charge of the acidic and basic groups, and causes the shape of the protein to change. This change, and changes induced at the active site, may prevent the substrate molecule from making a very close fit to an active sites and the reaction fails to happen.
Temperature is one of the main factors in which the experiment could have been controlled. The higher the temperature the faster the reaction will go, This is due to the fact that with increased temperature there is a increased kinetic energy of the molecules and hence greater reactivity (that is, both the substrate and the enzymes molecules are moving about more rapidly and therefore have more chance of collisions). In fact the rate of reaction increases by double every 10ºC. Yet there is a limit to how high the temperature can react since protein are actually denatured by heat. Heat denaturation really represents an irreversible destruction of the tertiary structure of an enzyme protein, changing its shape, and eventually destroying the active sites. As a result there is an apparent optimum temperature, which is about 37ºC. figure
2 shows describes the affects of heat more clearly
Substrate concentration is also important in controlling the reaction. A low concentration will result in a rapid reaction while a high concentration will end with a slow reaction this is due to the fact that since there are less enzymes presence than substrate. Some substrate will have to wait while the others are reacting.
Enzymes differ from most inorganic catalysts in that they catalyst only one reaction or a small range of reactions, while inorganic catalyst isn’t highly specific.
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