Denaturing Flashcards
What 3 things can denature a protein?
Heat, pH, detergents
How do detergents denature proteins?
Detergents have a high affinity for non-polar structures so can disrupt hydrophobic interactions between side chains.
Resulting in the change of structure and exposure of hydrophobic residues to the outside of the protein structure
How does heat cause denaturation?
Heat gives extra energy to the system so the atoms vibrate within the structure, which can be so strong that bonds within the protein are broken and a new shape is taken up
List the 4 types of bonds from most energy needed to break to least
Covalent
Hydrogen
Electrostatic (ionic)
Hydrophobic
How does pH cause denaturation?
When pH changes the ionisation of some amino acids side chains changes changing their bonds and formation, maybe causing the unfolding of the tertiary structure
What are the components of a buffer solution?
A mixture of a weak acid and its conjugate base
What is the equation of the acid dissociation constant?
Ka = [H+][A-]/[HA]
How does a buffer work?
Buffers minimise the change in pH in response to an increase or decrease in [H+] in solution. Whenever the free acid and conjugate base are mixed together the proportions adjust until Ka = [H+][A-]/[HA]. A buffer works well because this ratio is constantly maintained
What 2 biological buffers are important and what weak acids are they both based on?
Phosphate buffer: H3PO4
Bicarbonate buffer: H2CO3
Describe the mechanism of the phosphate buffer?
Phosphoric acid has 3H atoms which can be replaced –> dissociated is 3 stages:
H3PO4
H2PO4-
HPO42-
PO43-
How is the bicarbonate buffer formed?
It is formed by dissolving CO2 in water
What are the applications of the bicarbonate as a buffer in biological systems?`
It is under close control with CO2 controlled by respiration and HCO3- controlled by the kidneys
