Explain how amino acids may be grouped according to the physical and chemical properties of the R group?

Question

Explain how amino acids may be grouped according to the physical and chemical properties of the R group?

Thanks

Answer 1

There are 20 distinct AA that our body utilizes, however, there have been more than 20 discovered. How these amino acids differ from each other is by their so called "R" groups. You have the Aromatic R groups such as tryptophan and tyrosine phenylalanine, the hydrophobic r- groups (water fearing) which include the aromatics and leucine, valine, isoleucine and methionine. And you have the hyrdophilic (water loving) glutamine, aspartic acid, glutamic acid, his, lysine, arg. Essentially, the non polar AA will predominantly hydrocarbons, whereas the polar aa will have electronegative elements such as F, O, Cl, N. Why this is important is because a protein will fold according to what R groups are involved. If you have a chain of Hydrophobic Amino acids and its in a water solution, the amino acid will fold in particular ways as to mimimize contact with water.