How Does Temperature Affect The Rate Of An Enzyme

Enzymes lower the amount of energy needed in a chemical reaction. This happens because enzymes are catalysts, so they speed up the activation rates that occur in living organisms. Without enzymes, it would be difficult to break down particles like food in the digestion system. Enzymes are all very specific to what chemical reactions they will work with, and the temperature, pH, and salt concentration have to be a specific levels in order for the enzyme to function. The structure of each enzyme has a fixed shape in which a certain the substrate will fit into. The sequence of the amino acids in the enzyme determines the enzymes shape and structure. The substrate is a substance that needs to fit into the active site of the enzyme. This will activate the enzyme. Not all molecules that interact with the enzyme have to be a substrate because they could be activators or inhibitors. Activators will increase the reaction rate, while inhibitors will decrease the
reaction rate. Many medicines are inhibitors because they can kill diseases. Other aspects of the enzyme like temperature, pH, and salt concentration play a major role in determining the shape of the enzyme. If any of these variables is altered, the enzyme will not work as efficiently because of the change in shape of the enzyme and affect the reaction rates.
Every enzyme has a specific temperature that it will function properly at. If the temperature of the enzyme is not met, then the enzyme will be considered inactive. If the temperature of the enzyme gets too high or too low, the enzyme will shut down. In a person, this can be seen as hypothermia, if the body temperature is to low, and hyperthermia, if the body temperature gets too low. The reason that this happens is because temperature change supplies energy that will break attractions between molecules, which can change the shape of the active site in the enzyme. Each enzyme has an optimal temperature. “This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells,” (Royal Society of Chemistry, 2004). This explains why the average temperature for a human being is 37.5 degrees celsius. People also get sick when their body temperature is not at a certain degrees because their enzymes are not at an optimal temperature. Usually, once the temperature of the enzyme has been corrected, the shape of the active site will return to normal. This is not always the case because some substances will break bonds that cannot be reversed. Substances that will do this are usually toxic chemicals. pH levels can affect the shape of an enzyme.
The pH scale is a scale that measures how acidic or basic a solution is by looking at the is. It runs on a scale from 0 to 14, 0 being most acidic and 14 being most basic. Most enzymes will function best at the neutral level of 7, but very few will function at very high or very low pH. Changes in pH can alter the shape of an enzyme's active site because it can affect polar and nonpolar intramolecular attractions and repulsive forces. Basically, this can cause molecules within the cell to move around in different ways that ultimately change the shape of the enzyme. After the enzyme’s active site has changed shape, the substrate will not longer fit, causing the enzyme not work properly. “If the pH climbs to an unacceptably high value called alkalosis then enzymes cease to function effectively,” (Sang, 2013). To avoid changes in pH, buffers are used. Buffers are a substance found in the blood that prevent changes in pH levels, which helps enzymes to function
properly.
Salt concentration is another factor that will cause the enzyme to denature and the shape of the enzyme will be altered. If salt concentration is too high, the bonds within the enzyme can be distrusted and interactions of molecules can be blocked off. When this happens new interactions may also occur. On the other hand, when salt concentration is too low the amino acids in the enzyme will attract to each other. If either of these happen, the shape of the enzyme will be changed.