Question

How does temperature and pH affect the ability of an enzyme to bind substrate? and what specific changes occur to the structure of an enzyme when it is boiled?

Answer 1

Effect of pH and temperature on enzyme activity:

Every enzyme have an optimum pH and temperature at which the enzyme activity is at its best. First of all, let's talk about pH. Every enzyme works at an optimum pH (which is generally around 7). If the pH changes above or below the optimum pH, then the substrate binding sites (active sites) of the enzyme are damaged and the substrates no longer fits into the binding sites which results in no reaction.

Similarly, temperature also affects the enzyme activity. At optimum temperature (around 37 degrees) the enzymes shows highest enzyme activity. An increase in the temperature causes the frequency of collisions between the molecules to increase. Further rise in the temperature results in the damage of the binding sites and change in their shape. Due to this, the substrate binding to the active sites is hampered.

Effect of boiling on enzyme:

Upon boiling, enzymes initially an increase in their rate of enzyme activity is seen. But after some time when the temperature reaches beyond the optimum temperature, the enzymes stop working and becomes denatured due to the breaking of bonds between amino acids. Hence, the three dimensional structure of the enzyme is damaged resulting to damaged substrate binding sites.