Enzymes

• Enzymes are proteins that catalyse specific chemical reactions without being altered themselves
• Features of enzymes:

  • Enzymes are proteins
  • They speed up chemical reactions by lowering the activation energy needed to start the reaction
  • Enzymes are not used up in the reaction
  • Enzymes are reaction-specific and work under specific conditions like pH and temperature
  • Enzymes are thought to work on a lock and key model
• Activation energy is the energy needed to start a chemical reaction. Enzymes function by lowering activation energy
• Lock and key model:

  • The substrate attaches to the active site on the enzyme forming an enzyme-substrate complex
  • The enzyme weakens the chemical bonds, causing the substrate to break down into two smaller product molecules
  • The products leave, and the enzyme is unaltered and free to catalyse the breakdown of another substrate molecule
• Factors affecting enzymes:

  • Concentration of Enzyme: More enzyme available leads to faster reactions
  • Concentration of Substrate: More substrate available allows faster attachment and reaction
  • Temperature: Enzymes have an optimal temperature; too low or too high temperatures affect enzyme activity
  • pH: Enzymes have an optimal pH level for efficient function
  • Cofactors: Inorganic chemicals like Mn, Fe, Co, Ni, Cu, Zn, and Mb are required for enzyme function
  • Coenzymes: Inorganic molecules derived from vitamins like B2, B3, B5, C, and K are needed for some enzymes to work
• The enzyme lowers the activation energy required to start the reaction, so it speeds up the reaction.
• Enzymes are proteins that catalyse specific chemical reactions without themselves being altered
• All enzymes speed up chemical reactions by lowering the energy needed to start the reaction (activation energy)
• Enzymes are not used up in the reaction and are reaction specific, working under specific conditions like pH and temperature
• Enzymes are thought to work on a lock and key model where the substrate attaches to the active site on the enzyme forming an enzyme-substrate complex
• In the lock and key model, the enzyme causes weakening of the chemical bonds, resulting in the substrate breaking down into two smaller product molecules, which then leave
• Factors affecting enzymes:

  • Concentration of Enzyme: the more enzyme available, the faster the reaction will occur
  • Concentration of Substrate: the more reagent available, the faster the enzyme can attach to it, and the faster the reaction will occur
  • Temperature: enzymes have an optimal temperature; if it's too low, the enzyme doesn't work, and if it's too high, the enzyme denatures
  • pH: enzymes have an optimal pH level – they do not work as well outside this region
• Activation energy is the energy needed to start a chemical reaction, and enzymes function by lowering activation energy
• Cofactors are inorganic chemicals required for enzymes to work, including Mn, Fe, Co, Ni, Cu, Zn, and Mb