Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Question about amino acids....?
So I am in biochem, and one of my homework questions is why amino acid sidechain ionizable groups often have pK values that differ significantly from those of the isolated amino acid?
Now if you could help me fill in the gaps in my answer or lead me in the direction I would appreciate it. I have that ionizable groups can be in one of two states, neutral or charged. Also they are farther removed from the main structure and thus have varying properties, and they also alter the pI.
Help me if you can, I appreciate it.
1 Answer
- IndogLv 51 decade agoFavorite Answer
Be sure to consider the functional groups of the side chains, as well. If side chains possess carboxyl groups or amino groups, they might have similar pKa values to these two groups on the core amino acid by virtue of being the same functional group. However, if the side chain possesses a hydroxyl group, this is different from either a carboxyl or amino group and inherently has a different pKa.
You are correct in that proximity affects pKa values, and this would be important in explaining differences between two of the same functional group. If they are radically different, it is probably due to functional group composition.
