Protein DLA -Structure And Function Flashcards
What is protein folding?
Folding allows formation of the native(functional) protein form
What processes do protein folding depend on?
Folding is a trial and error process that depends on :
- Composition of side chains
- Hydrogen bonding
- Disulfide bonds
The - Ionic interactions
- Hydrophobic effect
- All in the context of repulsion of some shapes(steric, charge, bond angle constraints)
What is the purpose of protein folding?
To result in the most stable or favorable structure
Outline the process of protein folding
- Formation of secondary structures
- Formation of domains
- Formation of final protein monomer
Denaturation is usually….
Irreversible
In rare cases, denaturation is reversible (RNAse A)ribonuclease A
What is lost due to denaturation?
- loss of biological activity
- all other shape / conformational structure
How does denaturation affect primary structure?
Primary structure stays intact
List some denaturation agents
- heat
- organic solvents
- mechanical shearing
- heavy metals
- detergents
- chaotropic
- drastic change in pH
Where can RNAse be found?
On the hand
What happens if denaturing agents are removed from RNAse after it is denatured?
RNAse, forms right back
What are Chaperones?
Molecules that prevent inappropriate protein to protein interactions by:
- keeping unfolded proteins separate
- enhance folding rate
- Protect side chains from inappropriate interactions
What are Heat Shock Proteins?
A special type of chaperone
What is the purpose of Heat Shock Proteins?
Their synthesis increases in response to high temperature and other conditions which increase protein denaturation in the cell e.g. HSP70
What are proteases?
Enzymes that degrades the protein
How do protease break down proteins?
Breaking the peptide bond
What may cause non-enzymatic protein degradation?
- Very low pH or very high pH
- Heat
- Time
- doesn’t happen naturally
Does protein degradation occur in the stomach? Why?
Does not occur in the stomach.
The pH is not low enough, Heat is not high enough and not enough time
What happens to dietary protein in the stomach?
Dietary protein is not degraded, but it is denatured
- denatured means the proteins unfolds
- loss of conformation/shape
What is the job of the stomach?
To denature proteins, so they are easier to degrade by digestive enzymes
What are chemicals and conditions that promote protein denaturation, giving a reason for each
- Heat, pulls stuff apart
- stuff that alters changes ionic bonds and hydrogen bonding( e.g. salt, acid, base)
- detergent which allows hydrophobic areas to interact with water
- reducing agents which can break disulfide bonds
Detergents are _________ molecules
Amphipathic
Give an example of a detergent that can denature proteins
SDS- sodium dodecyl sulfate
What is sodium dodecyl sulfate used for?
SDS is in toothpaste
What is another name for beta-mercaptoethanol?
Ethanol thiol