Biology B2

Enzymes and their reactions catalysed

enzymereaction catalysed amylase starch    →    sugars protease proteins    →    amino acids lipase lipids    →    fatty acids + glycerol

Where enzymes are produced

enzymewhere produced amylase salivary glands, pancreas, small intestine protease stomach, pancreas, small intestine lipase pancreas, small intestine

The stomach produces hydrochloric acid. This helps to begin digestion, and it kills many harmful microorganisms that might have been swallowed along with the food. The enzymes in the stomach work best in acidic conditions - in other words, at a low pH.

After the stomach, food travels to the small intestine. The enzymes in the small intestine work best in alkaline conditions, but the food is acidic after being in the stomach. A substance called bile neutralises the acid to provide the alkaline conditions needed in the small intestine.

Uses of enzymes

enzymeuse protease used to pre-digest proteins during the manufacture of baby foods lipase used - together with protease - in biological detergents to break down - digest - the substances in stains into smaller, water soluble substances carbohydrase used to convert starch syrup, which is relatively cheap, into sugar syrup, which is more valuable - for example, as an ingredient in sports drinks isomerase used to convert glucose syrup into fructose syrup - fructose is sweeter than glucose, so it can be used in smaller amounts in slimming foods