The role of Enzymes

• Enzymes


  Biological catalysts that speed up the rate of chemical reactions without being used up or undergoing permanent change
• Enzymes


  • They are globular proteins with complex tertiary structures
  • Some are formed from a single polypeptide, whilst others are made up of two or more polypeptides and therefore have a quaternary structure
• Metabolic pathways


  Controlled by enzymes in a biochemical cascade of reactions
• Virtually every metabolic reaction within living organisms is catalysed by an enzyme
• Enzymes are essential for life to exist
• Intracellular enzymes


  Produced and function inside the cell
• Extracellular enzymes


  Secreted by cells and catalyse reactions outside cells (e.g. digestive enzymes in the gut)
• Intracellular enzymes


  • Catalase - breaks down hydrogen peroxide into water and oxygen
• Extracellular enzymes


  • Amylase - hydrolyses starch into maltose
  • Trypsin - breaks proteins down into peptides and amino acids
• Some organisms can only feed using a form of extracellular digestion in which the digestive enzymes are actually secreted outside of their bodies
• Extracellular digestion in fungi

  • The hyphae of fungi secrete the necessary enzymes directly onto the food they are consuming (e.g. wood) so that the food is digested into smaller, simple molecules that the fungi can then absorb through the walls of the hyphae