1.4 Flashcards
Heating
Melts protein
pH variation
Changes charge distributions by altering ionization of amino side chains
Detergents (amphipathic molecules)
Associate with non polar residues and disrupt hydrophobic interactions
Chaotropic agents (urea, guanidinium, chloride)
Disrupt intermolecular interactions
Anfinsen experiment
Primary amino acid sequence was sufficient to determine structure
Problem: Non-native disulfide bridge formation
Solution: Protein Disulfide Isomerase (PDI)
Problem: Isomerization of Proline
Solution: Peptidyl Proline Isomerases
Problem: Aggregation
Solution: Chaperone proteins
What did levinthal conclude based on his paradox?
Protein folding is a random process
Which amino acid is most likely to be found in the interior of a protein?
Non polar amino acids
Which weak intermolecular force contributes the least to stabilizing the native gold of proteins, the most?
-ionic interactions (least)
-van der waals & hydrophobic (most)
What is the length of the funnel mean?
Enthalpy
Which characteristic is the same for both denatured and native proteins?
Covalent bonds in the peptide backbone
In Anfinsens experiment why did the removal of urea result in a small amount of reconstituted ribonuclease enzyme activity?
Because the removal of urea allowed hydrogen bonds and ionic interactions to reform
Explain the change in enthalpy and entropy that occur during protein folding, what causes these changes? Are they favorable to folding?
When proteins fold they become more ordered which decreases enthalpy which is not favored. This is counterbalanced by decrease in enthalpy and an increase in entropy due to the release of ordered water
