IUBMB Enzyme Nomenclature


Accepted name: 3-hydroxy acid dehydrogenase

Reaction: L-allo-threonine + NADP+ = aminoacetone + CO2 + NADPH + H+ (overall reaction)
(1a) L-allo-threonine + NADP+ = L-2-amino-3-oxobutanoate + NADPH + H+
(1b) L-2-amino-3-oxobutanoate = aminoacetone + CO2 (spontaneous)

Glossary: L-allo-threonine = (2S,3S)-2-amino-3-hydroxybutanoic acid
aminoacetone = 1-aminopropan-2-one
L-2-amino-3-oxobutanoate = (2S)-2-amino-3-oxobutanoate

Other name(s): ydfG (gene name); YMR226c (gene name)

Systematic name: L-allo-threonine:NADP+ 3-oxidoreductase

Comments: The enzyme, purified from the bacterium Escherichia coli and the yeast Saccharomyces cerevisiae, shows activity with a range of 3- and 4-carbon 3-hydroxy acids. The highest activity is seen with L-allo-threonine and D-threonine. The enzyme from Escherichia coli also shows high activity with L-serine, D-serine, (S)-3-hydroxy-2-methylpropanoate and (R)-3-hydroxy-2-methylpropanoate. The enzyme has no activity with NAD+ or L-threonine (cf. EC, L-threonine 3-dehydrogenase).

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Fujisawa, H., Nagata, S. and Misono, H. Characterization of short-chain dehydrogenase/reductase homologues of Escherichia coli (YdfG) and Saccharomyces cerevisiae (YMR226C). Biochim. Biophys. Acta 1645 (2003) 89-94. [PMID: 12535615]

[EC created 2014, modified 2015]

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