Proteins

• Proteins 


  The most diverse macromolecule
• Protein functions 


  • Catalyst
  • Structure
  • Storage
  • Transport
  • Cellular communication
  • Movement
• Polypeptides (proteins)


  The most diverse macromolecule
• Protein functions


  • catalyst
  • structure
  • storage
  • transport
  • cellular communication
  • movement
• Polypeptides 


  made from joining monomers called amino acids
• Chemical formula 


  R-CH(NH2)COOH
• Amino acids 


  have an amine group and a carboxyl group
• Amine group 


  (H2N) or (NH3)
• Carboxyl Group


  COOH
• R group 


  variable
• Peptide Bonds 


  bonds between amino group of one AA (amino acid) and the carboxyl group of another AA
• Peptide bond

  
• How does a peptide bond form?


  Peptide bonds are formed as two amino acids join to form a protein. Peptide bonds form through a process called dehydration synthesis
• Enzymes

  The most important types of protein
• Enzyme functions


  • catalyst: speeds up reactions, not consumed, can function over and over
  • carryout cellular processes
• Conformation


  shape of protein
• shape of protein 


  determines function
• Primary structure 


  order of amino acids
• Secondary structure 


  Result of H-bonds between amino acids

  • Alpha Helix: chain joined to self
  • Beta-pleated Sheets- joined another chain/region
• Tertiary structure 


  the overall shape of a polypeptide

  Result of:

  H-Bonds, Van der whals interactions, disulfide bonds, hydrophobic reactions
• Quarternary structure 


  2 or more polypeptide chains joining

  Also the result of the same from the tertiary structure
• What determines protein shape


  • order of AA
  • Environmental conditions: temperature and pH
• Denaturation


  Polypeptide loses shape and is no longer active (unfolds)
• Renaturation


  Refolding of protein= "colder"