The Effect of High Temperatures on Enzymes

One of the reasons the body's temperature is so carefully controlled to stay in a narrow range is that it affects how different chemical reactions work. Changes in temperature can affect the activity of special proteins known as enzymes, which are needed for many of the processes essential to life.

Enzyme Mechanism

Enzymes are proteins that all organisms use to cause chemical changes, MedLinePlus explains 1. One of the interesting things about enzymes is that although they can cause a permanent change in the chemical structure of a substance, the enzymes themselves do not change, which means that one enzyme molecule can be used repeatedly. Enzymes can be used to make new structures and break down compounds, and can be found in virtually every living cell because enzyme function is essential to life.

Temperature and Kinetic Energy

To a certain extent, rising temperatures speed up the rate at which enzymes work, Worthington Biochemical Corporation explains 2. When temperature is increased, molecules come together more frequently and with greater energy. Because chemical reactions need a certain amount of energy to occur, increasing the energy of the molecules involved in the reaction can speed up the rate at which the reaction occurs. Consequently, enzymes are able to work more quickly in higher temperatures, but only to a certain point.

Temperature and Denaturation

Although increased temperatures can cause enzymes to work more quickly, if the temperature gets too high the enzyme stops working. Enzymes rely on having a very specific three-dimensional structure to work right. If the temperature around an enzyme gets too high, the enzyme loses its shape, which is known as denaturation, and ceases to work. Most enzymes will become denatured at very high temperatures.

Thermophiles

One of the exceptions to the general rule that very high temperatures cause enzyme denaturation occurs with thermophiles. Thermophiles, according to the University of Colorado, are organisms that live at very high temperatures, such as:

• in geothermal springs
  
• underground
  
• where the temperature can be hotter 3

These organisms have enzymes that are designed to function optimally at very high temperatures to allow the organisms to live.