Structure and Function of Protein

Structure and Function of Protein

1. Structure

   • Primary
     • Arrangement of amino acids in the polypeptide by peptide bonds
   • Secondary
     • Polypeptide folds into alpha helix or beta pleated sheets
     • Stabilised by repeated hydrogens bonds
   • Tertiary
     • 3D structure from secondary & forms functional protein
     • Maintained by Hydrogen binds, Disulfide bonds & Van der waals forces
   • Quanternary
     • Several polypeptides join to form one functional protein
     • Held together by non-covalent forces
     • Eg: Haemoglobin

2. Functions

   • Catalytic Protein: Enzymes
   • Protection: Immunoglobulin
   • Transport: Haemoglobin
   • Structural: Collagen
   • Regulation: Hormones
   • Genetic: Histones
   • Immunity: Antibodies

3. Amino Acids (building blocks of protein)

   • Contains: Carbon, hydrogen, oxygen, nitrogen. Sulphur & phosphorous as minor components
   • Most amino acids are alpha-amino acids except proline