Enzymes are biological catalysts which speed up the reaction rate without getting involved in the reaction itself.

Photo by Science in HD

Examples of Enzymes

  1. Salivary amylase
  2. Pepsin
  3. Renin
  4. Lipase
  5. Catalase
  6. Isomerase
  7. Phosphorylase
  8. Maltase
  9. Lactase
  10. Sucrase…etc

Types of Enzymes

  1. Carbohydrase- digests carbohydrates (eg:- Salivary amylase)
  2. Protease- digests proteins (eg:- pepsin)
  3. Lipase- digests fats (eg:- Enzymes from pancreas)

How an Enzyme works

  1. An enzyme has an active site similar to the shape of the substrate.
  2. When an enzyme comes in contact with the substrate, it fits like a jigsaw and exerts pressure onto the substrate at a specific point so that it breaks up into a simpler substance.

Properties of Enzymes

  • All enzymes are proteins
  • All enzymes work best at a specific temperature, known as the optimum temperature
  • Enzymes get denatured ( lose shape of their active site) if it’s optimum temperature is exceeded
  • Enzymes even work the fasted at a specific pH and like temperature, get denatured when the pH exceeds the optimum
  • Enzymes are specific in nature ( they can only break down a specific substrate)

Factors affecting Enzymes


  • As the temperature of a reaction mixture increases, the kinetic energy inside the reacting particles increases as well
  • This leads to a high collision frequency to build up
  • This causes the substrate and the enzyme to collide more frequently and thus increase the rate of reaction.
  • However, at a certain temperature, the enzyme loses the shape of it’s active site resulting in rate of reaction to drastically fall.


  • The pH for any enzyme to work depends upon it’s environment of production
  • For most enzymes in the human body, the optimum pH is 7 (neutral)
  • However, there are a few exceptions such as pepsin the enzyme that works in the stomach where dilute hydrochloric acid is secreted and pH is as low as 2
  • Enzymes can work at pH slightly higher or lower than their optimum pH

Using Enzymes

Uses in biological washing powders

  • In order to break down organic substances such as carbohydrates,proteins and fats (that chemical detergents fail to break), such biological catalysts are used
  • Organic stains such as blood, oil, egg, butter etc. are broken down to simpler substances in the presence of proteanases.
  • Enzymes need to have an optimum temperature of at least 70 degree celsius and hence are extracted from thermophilic bacteria or bacteria living near hot springs to remove the other componants of the dirt and so that other parts of the detergant work well as well.
  • The enzymes found in these bacteria are majorly proteases and lipases.
  • In order to keep these biological catalysts away from skin contact (as proteases can digest skin cells made up of protein!), they are packed in microscopic packets that only dissolve in the presence of water.

Uses in the food industry

Photo by Eiliv-Sonas Aceron
  • Fruits contain a substance known as pectin that is present within the primary and secondary cell walls of the fruit cell
  • In industrial fruit juice extraction, an enzyme called as pectinase is used to break down the pectin present so that it is more easier to squeeze the juice out
  • This relatively increases the volume of juice extracted and thus makes it economical for the company.
  • Other than fruit juices, enzymes are also used in baby food production where the food is treated with proteases and carbohydrases to break it down to simpler substances.
  • This helps the baby’s body to easily absorb the food with indigestion prevented.
  • Another use of enzymes is in sugar syrup production where amylase is used to break down starch to the sweet tasting disaccharide- Maltose.

External Links

  1. Enzyme
  2. Catalysis

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