Catalyzes the NAD(+)-dependent oxidation of L-threonine to 2-amino-3-ketobutyrate. To a lesser extent, also catalyzes the oxidation of L-serine, D-threonine, butan-2,3-diol, butan-1,2-diol, and propan-1,2-diol and cannot oxidize other L-amino acids. Cannot utilize NADP(H) instead of NAD(H). L-threonine + NAD(+) = (2S)-2-amino-3-oxobutanoate + H(+) + NADH Binds 2 Zn(2+) ions per subunit. Optimum pH is 10.0. The catalytic activity of the enzyme increases up to 100 degrees Celsius. Thermostable, has a half-life of 11 minutes at 100 degrees Celsius, 36 minutes at 90 degrees Celsius and 100 minutes at 80 degrees Celsius. Amino-acid degradation; L-threonine degradation via oxydo-reductase pathway; glycine from L-threonine: step 1/2. Homotetramer. Belongs to the zinc-containing alcohol dehydrogenase family.