Alanine
has a methyl R-group
Arginine
Has a guanidino group
Asparagine
has a 1-C amide R-group
Aspartic Acid
has a beta-carboxylic acid R-group
Cysteine
has a sulfhydryl group
Glutamic Acid
has a gamma-carboxylic acid R-group
Glutamine
has 2-C amide R-group
Glycine
has no chiral center
Histidine
has an imidazole ring
Isoleucine
has an sec-butyl R-group
Leucine
has a isobutyl R-group
Lysine
has a 4-C amine R group
Methionine
has a thioether (RSR’)
Phenylalanine
has a phenyl ring
Proline
has an imino group
Serine
has a 1° -OH group
Threonine
has a 2° -OH group
Tryptophan
has an indole ring
Tyrosine
has a phenol group
Valine
has an isopropyl R-group