3.1.4 Proteins Flashcards
Describe an enzymes structure.
• An enzyme is a type of protein.
• Proteins have a primary structure that is formed by a sequence of amino acids that are joined by peptide bonds in a condensation reaction.
• The primary structure folds into a secondary structure of either alpha helix or beta pleated sheets and these are held together by hydrogen bonds.
• The secondary structure further folds into a tertiary 3D structure that is held together by hydrogen bonds, ionic bonds and disulphide bridges.
• Folding of the amino acid chain into the tertiary structure dictates the shape of the active site, which is complementary to the substrate.
How does a competitive inhibitor work?
• Inhibitor binds to active site.
• Which prevents the substrate from binding to the active site.
• Meaning there are fewer enzyme substrate complexes being formed.
How does a non-competitive inhibitor work?
• Inhibitor binds to allosteric site.
• Which changes the shape of the tertiary structure and therefore active site.
• Meaning the substrate is no longer complementary to the active site.
• So fewer enzyme substrate complexes form.
Information about proteins. Click for more. 😉
• Amino acids contain C, O, H and N.
• They have a carboxyl group and an amine group.
• They also have an R group which can change the properties of the amino acid.
• There are 20 amino acids.
• They react in a condensation reaction and are joined by a peptide bond.
• A polymer of amino acids is called a polypeptide.
Describe the structure of a protein.
• Proteins have a primary structure that is formed by a sequence of many amino acids that are joined by peptide bonds in condensation reactions.
• The primary structure folds into a secondary structure of either **alpha helix **or beta pleated sheets and these are held together by hydrogen bonds.
• The secondary structure further folds into a tertiary 3D structure that is held together by hydrogen bonds, ionic bonds and disulphide bridges.
• Some proteins e.g. antibodies may form a quaternary structure of more than one polypeptide chain(some of these may have prosthetic groups e g. haem).
