Protein

[Temperature101]

Transferring a protein from a 1 M electrolyte solution to a 0.1 M electrolyte solution would most likely have which of the following consequences for the protein?

A. Protonating acidic residues while deprotonating basic residues

B. Protonating acidic residues and protonating basic residues

C. Deprotonating acidic residues and deprotonating basic residues

D. Deprotonating acidic residues while protonating basic residues


Answer: A .... Why?

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[dontbeanegaton]

I would choose D.
A 0.1 M electrolyte solution could be expected to have neutral pH relative to a 1 M solution, since [H+] counts as an ion.
At neutral pH, basic parts of the amino acid are protonated; acidic parts are deprotonated. Amino acids are zwitterions.
My two cents.

 

[Temperature101]

I would choose D.
A 0.1 M electrolyte solution could be expected to have neutral pH relative to a 1 M solution, since [H+] counts as an ion.
At neutral pH, basic parts of the amino acid are protonated; acidic parts are deprotonated. Amino acids are zwitterions.
My two cents.

I chose D as well but the answer is A.

 

[dontbeanegaton]

I chose D as well but the answer is A.

Didn't see your spoiler answer there. That makes no sense to me, then. I'm not sure how any conditions could have that effect on a molecule.

 

[orangeballoon]

You are transferring a protein from a more ionizable environment to a less ionizable. The 1M solution electrolyte solution has more ions, (be it Cl-, Na+, or H+ ions) and thus the residues are more likely to be ionized, since they are stabilized by the charges in the solution. Thus in the 1M solution, the acidic residue would be more likely to be deprotonated to carry a negative charge and the basic protonated to carry a positive charge. When transferred to the 0.1M environment, the residues are less likely to be ionized, because of the lessening of the charges in the solution that would induce them to do so. The acidic residues would then be re-protonated and the the basic deprotonated (Answer A).

 

[ebasappa]

You are transferring a protein from a more ionizable environment to a less ionizable. The 1M solution electrolyte solution has more ions, (be it Cl-, Na+, or H+ ions) and thus the residues are more likely to be ionized, since they are stabilized by the charges in the solution. Thus in the 1M solution, the acidic residue would be more likely to be deprotonated to carry a negative charge and the basic protonated to carry a positive charge. When transferred to the 0.1M environment, the residues are less likely to be ionized, because of the lessening of the charges in the solution that would induce them to do so. The acidic residues would then be re-protonated and the the basic deprotonated (Answer A).

Very nice

 

[dontbeanegaton]

You are transferring a protein from a more ionizable environment to a less ionizable. The 1M solution electrolyte solution has more ions, (be it Cl-, Na+, or H+ ions) and thus the residues are more likely to be ionized, since they are stabilized by the charges in the solution. Thus in the 1M solution, the acidic residue would be more likely to be deprotonated to carry a negative charge and the basic protonated to carry a positive charge. When transferred to the 0.1M environment, the residues are less likely to be ionized, because of the lessening of the charges in the solution that would induce them to do so. The acidic residues would then be re-protonated and the the basic deprotonated (Answer A).

Wow. Good job.

 

[circulus vitios]

You are transferring a protein from a more ionizable environment to a less ionizable. The 1M solution electrolyte solution has more ions, (be it Cl-, Na+, or H+ ions) and thus the residues are more likely to be ionized, since they are stabilized by the charges in the solution. Thus in the 1M solution, the acidic residue would be more likely to be deprotonated to carry a negative charge and the basic protonated to carry a positive charge. When transferred to the 0.1M environment, the residues are less likely to be ionized, because of the lessening of the charges in the solution that would induce them to do so. The acidic residues would then be re-protonated and the the basic deprotonated (Answer A).

Why not assume it's an acidic solution? I figured transferring from 1M to 0.1M means increased deprotonation of the acidic residues due to decreased common-ion effect.

 

[Temperature101]

Why not assume it's an acidic solution? I figured transferring from 1M to 0.1M means increased deprotonation of the acidic residues due to decreased common-ion effect.

That was my interpretation as well...What a terrible question !