Reaction: L-threonine + NAD+ = L-2-amino-3-oxobutanoate + NADH + H+
Other name(s): L-threonine dehydrogenase; threonine 3-dehydrogenase; threonine dehydrogenase, THD
Systematic name: L-threonine:NAD+ oxidoreductase
Comments: This enzyme acts in concert with EC 2.3.1.29, glycine C-acetyltransferase, in the degradation of threonine to glycine. This threonine-degradation pathway is common to prokaryotic and eukaryotic cells and the two enzymes involved form a complex [2]. In aqueous solution, the product L-2-amino-3-oxobutanoate can spontaneously decarboxylate to form aminoacetone.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9067-99-6
References:
1. Green, M.L. and Elliott, W.H. The enzymic formation of aminoacetone from threonine and its further metabolism. Biochem. J. 92 (1964) 537-549. [PMID: 4284408]
2. Hartshorne, D. and Greenberg, D.M. Studies on liver threonine dehydrogenase. Arch. Biochem. Biophys. 105 (1964) 173-178. [PMID: 14165492]
3. Newman, E.B., Kapoor, V. and Potter, R. Role of L-threonine dehydrogenase in the catabolism of threonine and synthesis of glycine by Escherichia coli. J. Bacteriol. 126 (1976) 1245-. [PMID: 7548]
4. Epperly, B.R. and Dekker, E.E. L-Threonine dehydrogenase from Escherichia coli. Identification of an active site cysteine residue and metal ion studies. J. Biol. Chem. 266 (1991) 6086-6092. [PMID: 2007567]