The D-form of dihydroxyphenylalanine (D-dopa) is a less physiologic activity than the L-form. D-dopa can be converted to the active L form during unidirectional chiral inversion, at first, oxidatively deaminated by D-amino acid oxidase to its alpha-keto acid and then transaminated by dopa transaminase to L-dopa. D-dopa is commonly used experimentally to determine whether the pharmacological effects of levodopa are stereospecific.