Enzymes

Enzymes: An Overview

• Enzymes are biological catalysts - they speed up chemical reactions in living organisms.
• They are proteins, made up of long chains of amino acids.
• Each enzyme has a unique shape, which determines its function. This is known as the lock and key theory.

Enzymes and Temperature

• Enzymes have an optimum temperature. This is the temperature at which they work best, typically around 37°C in humans.
• Below this temperature, enzymes work more slowly. Above it, they may start to denature (change shape), which can permanently damage or destroy them.
• If the temperature becomes too high and the enzyme becomes denatured, it can no longer catalyse reactions – it has become inactivated.

Enzymes and pH

• Enzymes also have an optimum pH. This is the pH at which they work best. For most enzymes, this optimum pH is around 7, which is neutral.
• Extremely high or low pH values can denature (change the shape of) enzymes, rendering them inactivated.

Enzymes in Digestion

• Amylase is an enzyme that breaks down starch into maltose. It is found in the mouth and the small intestine.
• Protease enzymes break down proteins into amino acids. They are found in the stomach and the small intestine.
• Lipase enzymes break down lipids (fats and oils) into glycerol and fatty acids. They are found in the small intestine.

Enzymes in Food and Industry

• Enzymes are used to break down large molecules in food during digestion.
• They are used in food production, for example in brewing beer and making cheese.
• They are also used in biological washing powders to break down stains.