definitions

• primary structure


  sequence of amino acids bonded by peptide bonds
• secondary structure


  • folding of polypeptide chain
  • held in place with hydrogen bonds
  • alpha helix or beta pleated sheets
• Tertiary structure


  • further folding of polypeptide chain
  • held in place with hydrogen bonds
  • disulphide bridges
  • ionic bonds
  • amino acids with hydrophobic R groups orientate towards the center of the protein
  • hydrophyllic R groups orientate towards outside of protein
• quaternary structure


  more than 1 polypeptide chain