Lecture 4 Flashcards
Proteins
Primary protein structure.
linear polymer of amino acids, held together by covalent peptide bonds.
Secondary protein structure.
Coiling (alpha helix) or folding (beta pleated sheet) of a polypeptide due to H-bonding between amino acids.
Tertiary protein structure
3D folding pattern of a folding of a polypeptide due to weak interactions between the R group of the chain
Quaternary protein structure
The conformation of an oligomeric protein maintained by weak interactions. Proteins consisting of more than one amino acid chain, not all proteins have a quaternary structure.
Weak interactions
- H-bonding
- Ionic interactions
- Hydrophobic interactions
weak interactions are reversible, additive, and often short lived.
H-Bonding
H bonded to F, N, or O
Ionic interactions
Electrostatic interactions between permanently charged species, cations and anions.
Hydrophobic interactions
The tendency for non-polar molecules to congregate in water
Process of enzyme catalyzation
- substrates enter the active site of the enzyme
- substrates are held together in the active site by weak interactions
- active site can lower the activation energy to speed up a reaction
- the substrates are converted to products
- products are released and the active site is available for two new substrate molecules.
Enzyme
A protein that acts as a biological catalyst
Covalent bonds
Polar or Nonpolar. Hold atoms together to form molecules, such as H20, and breaking these covalent bonds requires a chemical reaction.
How does the structure of macromolecules relate to proteins?
A molecules biological function is dependant on the correct conformation. The structure determines the function of the protein. A change in one single amino acid can have a significant effect of the functioning of the protein.
Substrate
A substance that contains an active site for an enzyme to act on.
