Catalyzes the NAD(+)-dependent oxidation of L-threonine to 2-amino-3-ketobutyrate (PubMed:16233775, PubMed:15902509). Is much less efficient when using NADP(+) instead of NAD(+) (PubMed:16233775). To a lesser extent, also catalyzes the oxidation of L-serine and DL-threo-3-phenylserine, but not that of L-allo-threonine, D-threonine and D-allo-threonine and many other L-amino acids (PubMed:15902509). L-threonine + NAD(+) = (2S)-2-amino-3-oxobutanoate + H(+) + NADH Binds 2 Zn(2+) ions per subunit. Contains one structural ion and one catalytic ion that seems to be less tightly bound at the site (PubMed:16233775). Zn(2+) can be replaced by Mn(2+) or Co(2+) to some extent (PubMed:15902509). Is totally inhibited by EDTA in vitro. Optimum pH is around 10. Below and above pH 10, the marked decrease of activity is observed: the relative activities are 50, 22 and 55% at pH 9.5, 9.2 and 12, respectively. Is stable over a wide pH range: upon heating at 50 degrees Celsius for 20 minutes, the enzyme does not lose activity at pH 4.5-10.0. Optimum tempreature is 70 degrees Celsius. Extremely thermostable, the activity is not lost after incubation at 100 degrees Celsius for 20 minutes. Amino-acid degradation; L-threonine degradation via oxydo-reductase pathway; glycine from L-threonine: step 1/2. Homodimer (PubMed:16233775). Homotetramer; dimer of dimers (PubMed:17188300) (PubMed:15902509). The enzyme shows pro-R stereospecificity for hydrogen transfer at the C4 position of the nicotinamide moiety of NADH. Belongs to the zinc-containing alcohol dehydrogenase family.