L-threonine dehydrogenase (TDH)

L-threonine dehydrogenase (TDH) is an **NAD+-dependent mitochondrial matrix enzyme** that catalyzes the oxidation of L-threonine to 2-amino-3-ketobutyrate, the first step in one of the main pathways of threonine catabolism in prokaryotes and many eukaryotes[2][4][1]. The enzyme is often a **homo-tetramer** (in bacteria and archaea) or dimer (in some protozoa) with distinct catalytic and NAD-binding domains, belonging to the short-chain dehydrogenase/reductase family (SDR)[1][3][2]. **TDH is a non-functional pseudogene (SDR14E1P) in humans**—meaning no active TDH enzyme is produced in humans[2][3][4]. Therefore, TDH **is not a therapeutic target in human biology or medicine**. However, in certain parasites (notably _Trypanosoma brucei_, the causative agent of human African trypanosomiasis), TDH is functional and essential, making it an attractive **selective drug target** for antiparasitic agents[2][3]. TDH inhibitors have demonstrated trypanocidal activity in laboratory models[2][3]. In summary: **L-threonine dehydrogenase is a functional enzyme and valid drug target in some non-human organisms (notably protozoan parasites), but in humans it exists only as a pseudogene (SDR14E1P) and is thus not considered a therapeutic target or relevant receptor/enzyme for drug discovery**[2][3][4].

Other names

SDR14E1PShort chain dehydrogenase/reductase family 14E, member 1L-threonine-3-dehydrogenaseTDH

Enzyme inhibition (experimental context in parasites, not humans)