Each amino acid has an H2N, or amino group, which has an alkalinity about equal to that of ammonia; and each has a COOH or carboxyl group, which has an acidity about like that of citric acid.

The results were consistent with the view that degradation of these acids by (β-oxidation was taking place within the plant. Nature - β-Oxidation of ω-Phenoxyalkylcarboxylic Acids in the Flax Plant ...