N1-Acetylspermidine hydrochloride, an acetyl derivative of spermidine, serves as a substrate for polyamine oxidase and selectively elevates its levels in human colorectal adenocarcinomas.

Homoserine is a more reactive variant of the amino acid serine. In this variant the hydroxyl side chain contains an additional CH2 group which brings the hydroxyl group closer to its own carboxyl group allowing it to chemically react to form a five-membered ring.

Itaconic acid also known as itaconate belongs to the class of organic compounds known as branched fatty acids. These are fatty acids containing a branched chain. Itaconic acid exists as a solid soluble (in water) and a weakly acidic compound (based on its pKa). Itaconic acid has been detected in multiple biofluids such as sweat and urine.