8. enzymes

• structure of enzyme?

  globular, tertiary structure held by ionic, hydrogen and disulphide bonds between R groups.

  • gives specific 3D shape. has active site which fits shape of specific substrate.
• lock and key theory?

  • enzyme holds substrate in a way that the reaction occurs more easily.
  • each enzyme only catalyses one specific reaction, only 1 shape of enzyme fits into its precisely-shaped active site
• induced fit theory?

  when substrate enters active site, enzyme changes shape slightly fitting more closely around the substrate.

  only specific substrates induce the changes in shape of an enzymes active site