Explain how enzymes are able to differentiate between two mo

Explain how enzymes are able to differentiate between two molecules that have similar shapes and chemical groups like valine and threonine.

Solution

Enzymes exist in specific conformations with the grooves or pockets. These grooves are formed by the lines of specific amino acids.

Lock and key model of enzyme catalysis hypothesizes that the substrate possesses specific geometrical shape that exactly fits into the groove of enzyme. Means, the substrate structure is complementary to the active site of an enzyme.

Once the substrate binds to the enzyme, it forms temporary bonds and fit into the groove. The enzyme-substrate complex now triggers a specific reaction, and results in the formation of a product.

This theory does not include the structural changes that occur after substrate binding, and also fails to explain transition states. The binding of substrate to the enzyme is specific, which allows the enzyme to differentiate between the molecules