All Questions
10
questions
3
votes
0
answers
38
views
Assessing stability of protein used for interaction experiments after changing buffer from tris to HEPES
I have a protein with a theoretical $\mathrm{pI}~9.0$ currently stored in $\pu{25 mM}$ tris and $\pu{250 mM}$ $\ce{NaCl}$ $(\mathrm{pH}~8)$ at $\pu{−80 °C}.$ I need to do experiments in HEPES at $\...
- 488
0
votes
0
answers
31
views
Can Amphotericin B cross a lipid bilayer membrane in its zwitterionic form when it is loaded in the aqueous core of a liposome?
Can Amphotericin B cross a lipid bilayer membrane in its zwitterionic form when it is loaded in the aqueous core of a liposome? Or must it be uncharged in order to cross the lipid bilyer membrane of ...
- 11
1
vote
0
answers
46
views
Is there a computer program capable of showing protein conformational changes based on pH?
As it is known, changes in pH change the attractions between the groups in the side chains of the protein.
Acidification can, for example, cause protonation of the $\ce{COO-}$ end to $\ce{COOH},$ ...
- 111
4
votes
2
answers
828
views
Why does denaturation of albumen protein cause pH of solution to increase?
I'm interested in the denaturation of proteins by alcohols, specifically by ethanol.
I have devised a simple experiment in which I inject solutions of ethanol (of variable concentrations) into ...
- 151
4
votes
3
answers
626
views
Fitting multiple pKa's
I have three histidine residues that are next to each other in a protein. When I compute the fraction of unprotonated states for each individual histidine as a function of $\mathrm{pH}$ my titration ...
- 43
3
votes
1
answer
472
views
Positive charge on a zwitter ion at pH=7?
I faced this question. But I am having some problems understanding the solution to this:
How can the negative charge on the peptide vanish on $\pu{pH = 7}$? Suppose, we have some $\ce{H+}$ donor on ...
- 2,331
0
votes
2
answers
557
views
Is there a pH at which all proteins are negatively charged? How can it be determined?
I know that depending on the amino-acid-composition of the peptide the distance to the isoelectric point determines the charge. Is there a universal point at which all proteins are definitely ...
- 11
-5
votes
2
answers
2k
views
Where on the backbone does a peptide get protonated at low pH?
As a particular example, how does the backbone of a peptide look at $\mathrm{pH}~2$? Where does the backbone get protonated in such an acidic solution?
I know that at low $\mathrm{pH}$ the free ...
- 197
2
votes
0
answers
52
views
Effect of protein hydrophobicity on metal interaction
I'm studying how metals and proteins interact (metal-protein complexes). I've found that almost all proteins could bind with metal at higher $\mathrm{pH}$ values, but also found some proteins showed ...
- 21
2
votes
3
answers
4k
views
Buffer Capacity Calculation
I know buffer capacity is the following:
$$β=\frac{Δ(\ce{H+})}{Δ(\mathrm{pH})}$$ specifically the amount of acid/base that needs to be added to change pH by 1 unit.
If I have data about how pH of a ...
- 123