Question

How do extreme pH and temperature extremes affect enzymes?

Answer 1

Enzymes function best at a particular range of temperature and pH which is called their optimum range beyond which the enzyme does not function.

Complete answer:
Enzymes are the biological catalysts that speed up the rate of a biochemical reaction. They are proteins so they have primary, secondary, and tertiary in nature. They have a particular 3-D structure with an active site where the substrate molecule can fit. These structures are held in shape by different interactions like hydrogen bonding, sulfide bonding, ionic interactions, covalent interactions, etc.

Each enzyme has its own optimum range of pH at which the activity of the enzyme is highest. The extreme pH can affect these bonding or interactions especially the ionic bonds and hydrogen bonds which can disrupt the active site of the enzyme. Due to this substrate cannot fit in the active site of the enzyme and thereby affecting the functioning of the enzymes.

The enzyme has the highest activity at the optimum temperature when the temperature is increased beyond this the hydrogen bonds in the enzymes vibrate which breaks on a further increase of temperature thereby denaturing the protein structure and affecting the functionality of the protein.

Note: On increasing the temperature the activity of the enzyme increases initially due to the gain in kinetic energy of the substrate molecules and the enzymes which increases their interaction. But the further increase in temperature can denature the proteins and this decreases the enzyme activity.