Nucleophilicity Of Amino Acid Side Chains [closed]








**Closed**. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers.
 
 






---








**Want to improve this question?** Update the question so it focuses on one problem only by [editing this post](/posts/127099/edit).




Closed 3 years ago.








[Improve this question](/posts/127099/edit) 



Out of the side chains of **aspartic acid**, **methionine**, **threonine**, and **tyrosine**, which is the least nucleophilic? 




Aspartic acid < Tyrosine < Threonine < Methionine is the order of nucleophilicity of the amino acid side chains. So, Aspartic acid (neutral form) is the answer. Every side chain has a Oxygen or Sulphur (Methionine) group available for electron pair donation, but in Aspartic acid the Oxygen group has lesser inclination for donation of electron density ([due to resonance](https://chem.libretexts.org/@api/deki/files/12837/3.jpg?revision=1)). Moreover, the solvation layer surrounding the acid group of Aspartic acid makes the job of nucleophilic attachment even more tougher.


 1