L-Threonine Dehydrogenase (TDH)

L-Threonine Dehydrogenase appears to be an evolving pseudogene of L-threonine 3-dehydrogenase (TDH). In both prokaryotes and eukaryotes, TDH catalyzes the first of two steps in one of two L-threonine degradation pathways.

However, in human, the single gene with sequence similarity to TDH is not capable of encoding a functional TDH protein; the predicted protein lacks most of the C-terminus and parts of the NAD+ binding motif when compared to other species' TDH proteins. This suggests that the human gene is therefore a pseudogene. Transcripts of this gene are found in all tissues and alternatively spliced transcripts have been described. It is not known if these transcripts are translated, or if the possible protein product provides any functional role.