|  | Diet Nutrition | Nutrition

The Effect of Temperature on Enzyme Activity in Beef Liver

Enzymes are organic or biological catalysts that drive metabolic reactions. In order for a reaction to take place within cells, enzymes must be present. Enzymes are complex proteins that function within the closely controlled internal environment of an organism. In healthy cells, the temperature remains within a narrow range and enzymes are therefore easily denatured, or destroyed by variations in temperature. Under adverse temperature conditions, enzymes cease to function.

  1. Chemical Reactions

    • The chemical reaction created by an enzyme will typically increase as the temperature is raised. As a rule of thumb, a 50 degree increase in temperature will cause the reaction rate of the enzyme to double. Eventually, an optimum temperature is reached, above which the enzyme's activities will no longer increase. After this temperature cut-off point is reached, the enzyme begins to denature, and its chemical structure becomes affected, thus adversely affecting the chemical reaction for which it is responsible. The chemical reaction driven by the enzyme ceases to occur, as the smallest change in the protein's structure alters the enzyme's shape enough to hinder the formation of the enzyme-substrate complex that is required. The reason for this is that enzymes have not developed coping mechanisms to handle highly elevated temperatures, because they exist with living cells, which can only survive within a specific temperature range. In general, most enzymes are denatured once temperatures are elevated above 105 degrees.

    Hydrogen Peroxide Formation

    • Enzymes are organic proteins that accelerate the rate of reactions within living cells, but are themselves not altered by these reactions. Hundreds of different enzymes may be found in a single cell and each of these is responsible for a specific reaction. The enzyme catalase reacts with hydrogen peroxide to produce water and oxygen and thereby effectively removes this toxic byproduct that occurs through cell metabolism. A classic experiment exists to show how temperature affects enzyme activity, by showing how the production of hydrogen peroxide is affected by increases or decreases in temperature. In this experiment, beef liver puree is used as a reservoir for the enzymes. With increasing temperature, less hydrogen peroxide is produced, with in turn indicates that enzyme reactions have increased.

    Narrow Temperature Band

    • Mammals, such as beef cattle, have a relatively constant temperature. The temperature within the cells of their body remains equally constant. For this reason, enzymes are accustomed to function with a narrow temperature band and the chemical reactions that they produce, occur optimally within the same temperature range. Any deviation from the normal temperature range will negatively affect these vital chemical reactions.

Nutrition - Related Articles