Protein stability Flashcards
1
Q
what is def of denaturation?
A
- breakdown of protein structure up to primary but not breaking primary
- difficult to disrupt than higher level
2
Q
Why is primary structure so hard to disrupt?
A
- held together by covalent peptie bonds (C-N), stronger than intermolecular forces that form higher level structure
- less energy to disrupt higher level structure
3
Q
Denaturing agents
A
- temp, pH extremes, detergents, reducing agents
4
Q
How does temp extreme denature?
A
- optimized at body temp
- specific to reaction collisions at low or stability at high
5
Q
How does pH extreme denature
A
- disrupt charge based interactions, mostly tertiary and quarternary
- high pH: Lys loses pos
- low pH: Asp loses neg
- like dissolve like
6
Q
How does detergent denaturea/
A
- detergents: part polar and part nonpolar
- disrupt hydrophobic interactions, disrupt higher level
- SDS: lauryl sulfite
7
Q
Reducing agents
A
- disrupt covalent: disulfide bonds
- breakage is reduction: reform SH group
- 2 mercaptoethanol and dithioreitol
8
Q
What form of denaturing is urea?
A
- reversible denaturing of H-bonds that is reversed with removal of urea
9
Q
What is the significance of proteases in protein structure?
A
break down primary structure- catalyze hydrolysis of peptide bonds
- usu grouped by catalytic mechanism
- serine protease: use serine OH for cleavage
- Trypsin: C-term Lys-Arg
- amino peptidase/carboxy peptidase: cleave at respective terminal
