Biology – Mode of action of enzymes | e-Consult

The specificity of an enzyme refers to its ability to bind to only one particular substrate or a very small group of structurally similar substrates. This specificity arises from the complementary shape of the enzyme's active site and the substrate. The 'lock and key' or 'induced fit' models illustrate this precise interaction.

This specificity is fundamental to biological systems because it ensures that reactions occur in the correct sequence and at the correct location. Each enzyme catalyzes a specific reaction, and this prevents unwanted or incorrect reactions from occurring. For example, digestive enzymes are specific for particular types of food molecules, ensuring that food is broken down efficiently.

If an enzyme were to lose its specificity, it would be unable to bind to its intended substrate effectively. This could have serious consequences for biological systems.

• Metabolic disruption: Incorrect reactions could occur, leading to a disruption of metabolic pathways and potentially cell death.
• Inefficient digestion: Digestive enzymes might act on the wrong food molecules, leading to poor digestion and nutrient absorption.
• Toxic reactions: Enzymes might catalyze unwanted reactions that produce toxic byproducts.

Loss of specificity can occur due to mutations in the enzyme's gene, leading to changes in the amino acid sequence and the shape of the active site. This can result in a non-functional or poorly functioning enzyme.