All Questions
14
questions
-1
votes
1
answer
106
views
Will concentration of sodium hydroxide affect the result of chicken feather hydrolyzate if i don't standardized it?
The title of the paper:
Isolation and characterization of keratin from chicken feathers https://doi.org/10.1063/5.0002792
Here is the method:
Keratin was isolated by dissolving 5g of chicken feather ...
- 79
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
0
votes
1
answer
91
views
Weak acids compared to strong ones in pH > 7 solution
In the book of Molecular Cell Biology (Big Alberts) by Alberts, at page 46, it is stated that
Acids—especially weak acids—will give up their protons more readily if the concentration of > H3O+ in ...
- 149
0
votes
0
answers
346
views
How does the pKa of a neutral molecule inform the protonation state of its positively charged molecule?
Let's say we have some neutral molecule A and its protonated form, A+. The pKa of molecule A is known, but we do not know the pKa of molecule A+. Can the pKa of molecule A+ be determined only knowing ...
- 1,118
0
votes
1
answer
7k
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How do I calculate the ensemble-average net charge of an amino acid at given pH?
I am given an amino acid with an ionizable side chain at a certain pH. How do I determine the net charge of that amino acid when there are mixed protonation states of one or more of the groups at that ...
- 51
3
votes
0
answers
124
views
How to control pH in a fermenter based on the acid produced by mircoorganism
I have got a bioreactor with an aqueous medium which produces biomass (yeast; S.cerevisiae) after inoculation.
I am observing and collecting data over the whole process via probes/etc. on different ...
- 103
0
votes
1
answer
643
views
Peptide at pH=1
In the following peptide:
I want to know the net charge of the peptide at pH=1.
According to me the as the solution is acidic so every nitrogen will get protonated.
Hence the number of charge = ...
19
votes
1
answer
66k
views
How do I calculate the isoelectric point of amino acids, each of which has more than two values of pKa?
For most amino acids, the $\mathrm{pI}$ is simply the arithmetic mean of the amino and carboxyl $\mathrm pK_\mathrm a$s. However, for tyrosine and cysteine, which have more than one $\mathrm pK_\...
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1
vote
1
answer
2k
views
Charge of an amino acid sequence
I have the following problem:
A polypeptide has the following sequence (amino end on the left)
$$\mathbf{lysine - aspartic~acid-histidine-arginine-serine}$$
Using the $pK_a$ information that ...
- 111
4
votes
1
answer
555
views
Atmospheric Nitrogen gas and human body pH buffers
It looks like the human body doesn't have the ability to breakdown atmospheric $\ce{N2}$, as of now $\ldots$ So an enzyme like nitrogenase (found in cyanobacteria) fixes $\ce{N2}$ and produces $\ce{...
- 1,944
3
votes
2
answers
2k
views
Carbonic acid-hydrogencarbonate buffer system pH calculation?
I am learning about the pH of buffer solutions, and am slightly confused by my text book's calculation. For the blood's buffer system of carbonic acid and hydrogencarbonate ions as the conjugate case, ...
- 1,697
4
votes
1
answer
918
views
How do I know that an acid and conjugate base are present in equimolar amounts?
Acetylsalicylic acid is a molecule in several popular drugs such as Magnyl and aspirin. It has a $\mathrm{p}K_\mathrm{a}$ of 3.5.
I'm about to calculate the $\mathrm{pH}$ of a $\pu{0.010 M}$ solution ...
- 703
4
votes
1
answer
1k
views
Calculating charge of amino acids (am I doing it right?)
Please consider this picture of a peptide chain:
I've done some examining on the different amino acids and concluded that the chain is as follows:
Lys-Leu-Gly-Ser-Citrullin (variant of arginine).
I ...
- 703
6
votes
3
answers
4k
views
How can I measure the pH of high-viscosity fluids like dough?
I would like to measure the pH value of dough with a pH-Meter, to ensure a pH value of 4.1 (max). Because of the high viscosity I would thin down the dough with demineralized water for two reasons:
I ...
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