Enzymes and their Structure

In this free sample of the science revision tuition programme we discuss Enzymes and their Structure.

Enzymes and their StructureEnzymes are made of proteins, and proteins are made of long chains of amino acids. These get folded into specific shapes to allow the enzyme to perform its role in the cell.

Enzyme Active Site and Specificity

Every enzyme has an active site; this is the site that catalyses the reaction. The active site is a specific shape for the substrate. Each substrate, such as starch, has a specific shape and only the enzyme that breaks down starch – amylase has an active site that will fit starch into it. They usually only catalyse one reaction.

Lock and Key Model and Induced Fit Model of Enzyme Action

This simplified model is called the lock and key model of enzyme action. The enzyme is like the lock with a specific shape for the substrate that is like the key. The enzyme is not rigid in its structure and changes shape a little as the substrate is attached. The enzyme closes around the substrate to make a tighter fit – this is called the induced fit model.