destroyer #291 bio
- Thread starter 113zami
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Hello! 🙂 Amino acids have an N-terminus (amino end) and C-terminus (carboxyl group). One amino acid is different from another as a resulf of its variable group. This variable group is defined as R. So R means the pK value for the side chain. Since th amino acid has an amino group it too has a pK value. Glycine for instance does not because the R group is a hydrogen.
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This question is actually really confusing. Can someone simplify the destroyer's explaination?
Hi everyone. Sure thing, lets take a look at this problem.
They say sophisticated, but I say all you need to know is one fact.
pH > pKa: deprotonated
In words, when the pH value is greater than the pKa, the corresponding amino group or carboxyl group will be deprotonated, and by this I mean the amino group will be NH2 and carboxyl group would be O-
A) pH = 7
pH < pKa (9.2 or 10.8); thus protonated
They have deprotonated - =)
B) pH > all of the pK values given, ok amino groups are NH2 and carboxyl groups are negative. Since we have two amino groups, if they were protonated, it would be like putting two positive ends of a magnet together, and they would repel. Thus, the destabilizing effect of the amino groups is removed.
C) pH < pKa; all protonated, ok so carboxyl exists as OH, and amino groups are all NH2, remember that magnet analogy above .
D) pH < pKa; prot. and thus destabilize the ring
So remember only: pH > pKa: deprotonated to solve their sophisticated problem. Hope this helps.
They say sophisticated, but I say all you need to know is one fact.
pH > pKa: deprotonated
In words, when the pH value is greater than the pKa, the corresponding amino group or carboxyl group will be deprotonated, and by this I mean the amino group will be NH2 and carboxyl group would be O-
A) pH = 7
pH < pKa (9.2 or 10.8); thus protonated
They have deprotonated - =)
B) pH > all of the pK values given, ok amino groups are NH2 and carboxyl groups are negative. Since we have two amino groups, if they were protonated, it would be like putting two positive ends of a magnet together, and they would repel. Thus, the destabilizing effect of the amino groups is removed.
C) pH < pKa; all protonated, ok so carboxyl exists as OH, and amino groups are all NH2, remember that magnet analogy above .
D) pH < pKa; prot. and thus destabilize the ring
So remember only: pH > pKa: deprotonated to solve their sophisticated problem. Hope this helps.
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