A bacterial enzyme has the following temperaturedependent...

A bacterial enzyme has the following temperaturedependent activity.
(a) Is this enzyme more or less active at normal body temperature than when a person has a fever?
(b) What happens to the enzyme activity if the patient's temperature is lowered to $35^{\circ} \mathrm{C} ?$

Key Concepts

Temperature Dependence of Enzyme Activity

Enzyme-catalyzed reactions are highly dependent on temperature. As temperature increases, molecules move faster, which increases the likelihood of effective collisions between enzymes and substrates, thereby accelerating the reaction rate. This principle is integral in understanding how enzymes function under different thermal conditions, and why deviations from the optimal temperature lead to reduced activity.

Optimum Temperature for Enzyme Activity

Every enzyme has an optimum temperature at which its catalytic activity is maximized. At temperatures below this optimum, reaction rates tend to slow down due to lower kinetic energy among reacting molecules. In contrast, temperatures above the optimum can result in reduced activity as the enzyme may begin to denature, meaning its structure and active site are altered.

Enzyme Denaturation

When enzymes are exposed to temperatures that exceed their optimal range, they can undergo denaturation—a process where their three-dimensional structure is disrupted. Denaturation typically results in a loss or significant reduction in enzyme activity because the precise arrangement of amino acids at the active site, essential for substrate binding and catalysis, is compromised.

Effects of Temperature Variations on Enzyme Kinetics

Small changes in temperature can have a pronounced effect on enzyme kinetics. In environments where the temperature is lower than optimal, reaction rates decrease due to reduced molecular motion and fewer effective collisions. Conversely, while moderate increases in temperature may initially enhance activity, extreme temperatures—such as those encountered during a fever—can inhibit enzymes, especially those adapted to lower temperature ranges.

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