H-DL-Nva-OH is the derivative of L-norvaline which is an inhibitor of arginase.

β-Alanine is a non-specific endogenous agonist at the inhibitory glycine receptor.

H-Phg(4-OH)-OH is an endogenous metabolite.

L-Azetidine-2-carboxylic acid is an endogenous metabolite.

2-Aminoisobutyric acid is a rare, non-protein amino acid and end-product of pyrimidine metabolism, excreted in urine and found in some antibiotics of fungal origin.

D(-)-2-Aminobutyric acid is an unnatural amino acid serving as an important intermediate in pharmaceutical production.