Amanda’s Blog

The enzyme must be within a certain temperature range to function properly. At very low temperatures, the energy of a solution is very low. The molecules in the solution have less vibrational energy and tend to have fewer collisions. Because an enzyme’s activity depends on interactions between molecules of the enzyme and the substrate, the activity of the enzyme will decrease at very low temperatures. As temperature rises, the energy of the molecules is increased, therefore they have more collisions. As enzyme and substrate interactions increase, the activity of an enzyme will also increase, but only up to certain point. If the temperature continues to rise, the protein will denature, resulting in a decrease in enzyme activity. This is because the hydrogen bonds of the water external to the folded protein become disrupted. At lower temperatures, the enthalpy of the hydrogen bonds overcomes the entropy of the proteins. When the temperature rises to a certain point, these hydrogen bonds break and their enthalpic contribution is no longer great enough to overcome the entropy of the protein. This causes the protein to unfold into a more disordered form that requires less free energy.