3.3.13.2 proteins

• what are proteins?


  sequences of amino acids joined together by peptide links

  
• how can this reaction be reversed?

  by boiling the protein in 6.0 moldm-3 HCl for 25 hours in a hydrolysis
• how is the hydrolysis carried out?

  by enzymes - not so harsh conditions are required
• structure of proteins 


  complex structures which are held together with H-bonds, VDWs and sulfur-sulfur bonds
• primary structure 


  single polypeptide chain of amino acids

  
• secondary structure 


  an a-helix or B-pleated sheet held with hydrogen bonds

  
• tertiary structure 


  chains folded into a 3D coil with hydrogen and disulphide bonding

  
• disulphide bonding 


  sulfur-sulfur bonds that hold together tertiary structures are known as a disulphide bridge

  
• what does the disulphide bonding do?

  keep the protein structure stable by losing 2 hydrogen atoms