Which of the following side chain in an aminoacid is least polar?
Methyl side chain is the least polar side chain associated with the nonpolar aminoacid alanine. Polarity of amino acid refers to the ability of the side chain of amino acid to interact with water at biologic pH. Alanine is the least hydrophobic non polar aminoacid due to the methyl side chain. Ref: Principles of Biochemistry and Biophysics By B.S. Chauhan, Pages 149-155
Methyl
Carboxyl
Amino
Phosphate