1 AZH Azidohomoalanine 1.000 2 A3B D-vinylglycine 0.700 3 ABA Alpha-aminobutyric acid 0.700 4 DBB D-alpha-aminobutyric acid 0.700 5 DBU (2z)-2-aminobut-2-enoic acid 0.700 6 LPG (2s)-2-aminobut-3-ynoic acid 0.700 7 LVG L-vinylglycine 0.700