Enzymes

• What are the properties of Enzymes?

  • They are biological catalysts that speed up the rate of reaction
  • They are organic and made in organisms
  • They have a specific tertiary structure that is complimentary to a substrate
  • They lower activation energy
  • They can work in or outside a cell
  • They are effected by Temperature, PH, Enzymes, Inhibitors, and Substrate concentration
• Intracellular Enzymes:

  • Hydrogen peroxide is a toxic product of many metabolic pathways
  • The enzyme catalyze ensures that hydrogen peroxide is broken down to oxygen and water quickly, thereby preventing its accumulation

  
• Extracellular Enzymes:

  • Large molecules such as proteins and polysaccharides are too large to enter cells directly. They must therefore be broken down into smaller components first, which is done by extracellular enzymes.
  • Trypsin for example is a protease which are released from the cell and works outside of it.
  • Trypsin is produced in the pancreas and released with the pancreatic juice into the small intestine, where it acts on proteins
• Anabolism > Using multiple smaller substrates to create a larger product. (DNA polymerase) (condensation)

  Catabolism > Using one large substrate to make multiple smaller products. (catalyse) (hydrolysis)

  
• Activation energy:

  • Enzymes reduce the activation energy
  • They do this by providing an Active site where reactions occur more easily than elsewhere as they provide an alternative pathway, and the active site has a specific shape which places strain on bonds within the substrate

  
• Induced fit theory:

  • The active site has a particular shape
  • Initially, the active site is not the correct shape to fit the substrate
  • As the substrate approaches the active the site changes and the result is its perfect fit. (Enzyme substrate complex)
  • After the reactions have taken place, and the products have gone the active site returns to its normal shape (Enzyme product complex)