Order of increasing polarity: A. Alanine B. Valine C. Glycine D. Isoleucine
All aliphatic amino acids i.e. Glycine, Alanine, Valine, Leucine and Isoleucine are non-polar. Isoleucine is most non polar, followed by valine. Glycine is least non-polar out of all aliphatic amino acids.
D- B- A-C
B- C- A-D
A- D- C-B
D-A- B-C
Classification and metabolism of amino acids