What are enzymes?

  • Biological catalysts
  • Inside cells
    • protein/lipid synthesis
    • intercellular
  • Outside cells
    • digestion
    • extracellular
  • Globular proteins
  • Generally soluble in water
  • Functions
    • Speed up a reaction
      • Help build a larger molecule
      • Help breakdown a large molecule into multiple smaller ones

Activation energy

  • Amount of energy which needs to be supplied for a reaction to proceed.
  • Enzymes reduce activation energy requirements (due to their specific shape)

Induced fit hypothesis

  • Substrate molecules collide with enzyme’s active site

  • Enzyme molecule changes shape slightly. Active site fits more closely around substrate.

  • Enzyme-substrate complex (ESC) is formed.

  • Substrate destabilised

  • Product produced

  • Enzyme-product formed

  • Product leaves enzyme active site

  • All enzymes are globular proteins

    • More beta pleated sheets than alpha helix
  • Many hydrophilic R groups