Lactic acid is an organic acid. It is a chiral molecule consisting of two optical isomers L-lactic acid and D-lactic acid with the L-isomer being the most common in living organisms. Lactic acid plays a role in several biochemical processes and is produced in the muscles during intense activity.

Diethyl oxalpropionate also known as methyloxalacetic acid diethyl ester or diethyl methyloxalacetate is a member of the class of compounds known as beta-keto acids and derivatives. These compounds are organic compounds containing an aldehyde substituted with a keto group on the C3 carbon atom.

D(-)-2-Aminobutyric acid is the substrate of D-amino acid oxidase.